docs/superpowers/plans/2026-09-17-core-cli.md

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keycask core + CLI Implementation Plan

For agentic workers: REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (- [ ]) syntax for tracking.

Goal: A Swift package with KeycaskCore (vault model, passphrase-encrypted envelope, generator, resolution) and a keycask CLI that behaves identically on macOS, Linux, and Windows, covered by in-process and black-box tests.

Architecture: KeycaskCore depends on Foundation and swift-crypto only and holds every rule about entries, IDs, encryption, and lookup. The keycask executable wraps it with ArgumentParser commands and a small platform layer (paths, terminal, atomic write, clipboard). Tests in KeycaskCoreTests run in process; tests in KeycaskCLITests spawn the built binary and check stdout, stderr, and exit codes.

Tech Stack: Swift 6.4, SwiftPM, Swift Testing, swift-crypto 3.15 (Crypto, _CryptoExtras), swift-argument-parser 1.8.

Spec: docs/superpowers/specs/2026-09-17-keycask-design.md

Global Constraints

// swift-tools-version:6.4, Swift 6 language mode, platforms: [.macOS(.v14), .iOS(.v17)].
Dependencies are exactly apple/swift-crypto and apple/swift-argument-parser. Package.resolved is committed.
KeycaskCore imports only Foundation, Crypto, and _CryptoExtras. It never imports ArgumentParser, never spawns a process, never reads the environment.
Envelope: format 1, kdf.name "pbkdf2-hmac-sha256", 600000 iterations, 16-byte salt, ChaCha20-Poly1305 combined box, key 32 bytes, passphrase NFC-normalized UTF-8.
EntryID: 8 characters from abcdefghijkmnpqrstuvwxyz23456789.
Dates: ISO 8601 UTC, whole seconds. JSON: sorted keys.
Exit codes: 0 ok, 1 failure, 2 usage, 3 not found, 4 cannot decrypt, 5 ambiguous.
Masked secret string is exactly ********.
Clipboard timeout is 45 seconds. Password default length 24. Passphrase separator -.
No code comments that mention the history of the project or how it used to work. No attribution trailers in commits.
Every file passes swift format lint --strict.
Work happens on a branch. Tasks 1-8 go on branch core, merged through one MR. Tasks 9-15 go on branch cli, merged through a second MR. Never commit to main directly.

File structure

Package.swift
Package.resolved
NOTICE
.gitbay/ci.yml
Sources/KeycaskCore/
  KeycaskError.swift      error enum, exit codes, messages
  EntryID.swift           8-char random ID, Codable as a string
  Entry.swift             entry struct, tag normalization, second-truncated dates
  Vault.swift             entries, add/remove/update, resolve, filter, search
  VaultCodec.swift        deterministic JSON encode/decode of Vault
  Envelope.swift          file envelope, PBKDF2 + ChaChaPoly seal/open, parse/encode
  Generator.swift         random password and passphrase
  Wordlist.swift          EFF long list as one string literal (generated file)
Sources/keycask/
  main.swift              parse, run, map errors to exit codes
  Keycask.swift           root command, GlobalOptions
  Paths.swift             vault path resolution
  Terminal.swift          isatty, echo-off line read, y/N confirm
  Passphrase.swift        env var or prompt
  AtomicFile.swift        temp + fsync + rename, 0600 on Unix, MoveFileExW on Windows
  OpenVault.swift         load/save/create: ties paths, passphrase, envelope, codec, atomic write
  Output.swift            text, table, JSON, masking, --field
  Clipboard.swift         tool discovery, read/write, daemon handoff
  Commands/Init.swift
  Commands/Add.swift
  Commands/Show.swift
  Commands/Ls.swift
  Commands/Find.swift
  Commands/Edit.swift
  Commands/Rm.swift
  Commands/Generate.swift
  Commands/Clip.swift
  Commands/ClipboardDaemon.swift
Tests/KeycaskCoreTests/
  EntryIDTests.swift
  EntryTests.swift
  VaultTests.swift
  VaultCodecTests.swift
  EnvelopeTests.swift
  GeneratorTests.swift
  KeycaskErrorTests.swift
Tests/KeycaskCLITests/
  CLI.swift               harness: locate binary, temp vault, run with env
  InitTests.swift
  AddShowTests.swift
  LsFindTests.swift
  EditRmTests.swift
  GenerateTests.swift
  ClipboardTests.swift
  PathsTests.swift

Task 1: Package scaffold and CI

Files:

Create: Package.swift
Create: Sources/KeycaskCore/KeycaskCore.swift (temporary, deleted in Task 2)
Create: Sources/keycask/main.swift (replaced in Task 9)
Create: Tests/KeycaskCoreTests/SmokeTests.swift (deleted in Task 2)
Create: .gitbay/ci.yml
Create: .swift-format

Interfaces:

Produces: the package layout every later task adds files to.
Step 1: Create the branch

cd /Users/cmc/git/krz/keycask && git switch -c core

Step 2: Write Package.swift

// swift-tools-version:6.4
import PackageDescription

let package = Package(
    name: "keycask",
    platforms: [.macOS(.v14), .iOS(.v17)],
    products: [
        .library(name: "KeycaskCore", targets: ["KeycaskCore"]),
        .executable(name: "keycask", targets: ["keycask"]),
    ],
    dependencies: [
        .package(url: "https://github.com/apple/swift-crypto", from: "3.15.0"),
        .package(url: "https://github.com/apple/swift-argument-parser", from: "1.8.0"),
    ],
    targets: [
        .target(
            name: "KeycaskCore",
            dependencies: [
                .product(name: "Crypto", package: "swift-crypto"),
                .product(name: "_CryptoExtras", package: "swift-crypto"),
            ]
        ),
        .executableTarget(
            name: "keycask",
            dependencies: [
                "KeycaskCore",
                .product(name: "ArgumentParser", package: "swift-argument-parser"),
            ]
        ),
        .testTarget(name: "KeycaskCoreTests", dependencies: ["KeycaskCore"]),
        .testTarget(name: "KeycaskCLITests", dependencies: ["keycask"]),
    ]
)

Step 3: Write placeholder sources so the package builds

Sources/KeycaskCore/KeycaskCore.swift:

public enum KeycaskCore {
    public static let name = "keycask"
}

Sources/keycask/main.swift:

import KeycaskCore

print(KeycaskCore.name)

Tests/KeycaskCoreTests/SmokeTests.swift:

import Testing

@testable import KeycaskCore

@Test func packageBuilds() {
    #expect(KeycaskCore.name == "keycask")
}

Tests/KeycaskCLITests/CLI.swift (a real file, extended in Task 9; this version only locates the binary):

import Foundation
import Testing

enum Binary {
    static let url: URL = {
        #if os(macOS)
            for bundle in Bundle.allBundles where bundle.bundlePath.hasSuffix(".xctest") {
                return bundle.bundleURL.deletingLastPathComponent().appendingPathComponent("keycask")
            }
            fatalError("test bundle not found")
        #elseif os(Windows)
            return Bundle.main.bundleURL.appendingPathComponent("keycask.exe")
        #else
            return Bundle.main.bundleURL.appendingPathComponent("keycask")
        #endif
    }()
}

@Test func binaryIsBuilt() {
    #expect(FileManager.default.isExecutableFile(atPath: Binary.url.path))
}

Step 4: Write .swift-format

{
  "version": 1,
  "indentation": { "spaces": 4 },
  "lineLength": 100,
  "maximumBlankLines": 1,
  "respectsExistingLineBreaks": true,
  "rules": {
    "AlwaysUseLowerCamelCase": true,
    "NeverForceUnwrap": false,
    "NeverUseImplicitlyUnwrappedOptionals": true
  }
}

Step 5: Build and test

Run: swift build && swift test Expected: Build complete, two tests pass. Package.resolved now exists.

Step 6: Lint

Run: swift format lint --strict --recursive Sources Tests Package.swift Expected: no output. If it reports findings, run swift format --in-place --recursive Sources Tests Package.swift and re-lint.

Step 7: Write .gitbay/ci.yml

# Each step runs in its own `sh -c`; exports do not survive between steps.
# swiftly installs into $HOME, which persists across builds.
jobs:
  build:
    steps:
      - |
        set -eu
        command -v curl >/dev/null || { echo "runner is missing: curl"; exit 1; }
        if ! command -v "$HOME/.local/bin/swiftly" >/dev/null 2>&1; then
          curl -fsSL "https://download.swift.org/swiftly/linux/swiftly-$(uname -m).tar.gz" | tar -xz -C /tmp
          /tmp/swiftly init --assume-yes --skip-install --quiet-shell-followup
        fi
        . "$HOME/.local/share/swiftly/env.sh"
        swiftly install --use 6.4
        swift format lint --strict --recursive Sources Tests Package.swift
        swift build
  test:
    steps:
      - |
        set -eu
        . "$HOME/.local/share/swiftly/env.sh"
        swiftly install --use 6.4
        swift test
    paths-ignore:
      - docs/**

Step 8: Commit

git add Package.swift Package.resolved .swift-format .gitbay/ci.yml Sources Tests
git commit -m "Add package scaffold and CI"

Task 2: KeycaskError

Files:

Create: Sources/KeycaskCore/KeycaskError.swift
Create: Tests/KeycaskCoreTests/KeycaskErrorTests.swift
Delete: Sources/KeycaskCore/KeycaskCore.swift, Tests/KeycaskCoreTests/SmokeTests.swift

Interfaces:

Produces: public enum KeycaskError: Error, Equatable, Sendable with cases notFound(String), ambiguous(name: String, candidates: [Entry]), cannotDecrypt, corrupt(String), vaultExists(String), noVault(String), duplicateID(EntryID), io(String), usage(String), failure(String); properties exitCode: Int32, message: String.
Note: Entry and EntryID do not exist yet. Write this task with ambiguous(name: String, candidates: [String]) and duplicateID(String) and change them to the real types in Tasks 3 and 4.
Step 1: Delete placeholders

git rm -q Sources/KeycaskCore/KeycaskCore.swift Tests/KeycaskCoreTests/SmokeTests.swift

Step 2: Write the failing test

Tests/KeycaskCoreTests/KeycaskErrorTests.swift:

import Testing

@testable import KeycaskCore

@Suite struct KeycaskErrorTests {
    @Test func exitCodesFollowTheSpec() {
        #expect(KeycaskError.failure("x").exitCode == 1)
        #expect(KeycaskError.io("x").exitCode == 1)
        #expect(KeycaskError.corrupt("x").exitCode == 1)
        #expect(KeycaskError.vaultExists("x").exitCode == 1)
        #expect(KeycaskError.duplicateID("abcd2345").exitCode == 1)
        #expect(KeycaskError.usage("x").exitCode == 2)
        #expect(KeycaskError.notFound("x").exitCode == 3)
        #expect(KeycaskError.noVault("/p").exitCode == 3)
        #expect(KeycaskError.cannotDecrypt.exitCode == 4)
        #expect(KeycaskError.ambiguous(name: "gh", candidates: []).exitCode == 5)
    }

    @Test func messagesNameTheSubject() {
        #expect(KeycaskError.notFound("gh").message == "gh: not found")
        #expect(KeycaskError.noVault("/v").message == "vault /v not found (run `keycask init`)")
        #expect(KeycaskError.vaultExists("/v").message == "vault /v already exists")
        #expect(KeycaskError.cannotDecrypt.message == "cannot decrypt: wrong passphrase or damaged vault")
        #expect(KeycaskError.corrupt("bad json").message == "vault is corrupt: bad json")
    }
}

Step 3: Run test to verify it fails

Run: swift test --filter KeycaskErrorTests Expected: compile error, KeycaskError not found.

Step 4: Write the implementation

Sources/KeycaskCore/KeycaskError.swift:

public enum KeycaskError: Error, Equatable, Sendable {
    case notFound(String)
    case ambiguous(name: String, candidates: [String])
    case cannotDecrypt
    case corrupt(String)
    case vaultExists(String)
    case noVault(String)
    case duplicateID(String)
    case io(String)
    case usage(String)
    case failure(String)

    public var exitCode: Int32 {
        switch self {
        case .failure, .io, .corrupt, .vaultExists, .duplicateID: 1
        case .usage: 2
        case .notFound, .noVault: 3
        case .cannotDecrypt: 4
        case .ambiguous: 5
        }
    }

    public var message: String {
        switch self {
        case .notFound(let what): "\(what): not found"
        case .ambiguous(let name, let candidates):
            (["\(name): ambiguous, use an id:"] + candidates).joined(separator: "\n")
        case .cannotDecrypt: "cannot decrypt: wrong passphrase or damaged vault"
        case .corrupt(let why): "vault is corrupt: \(why)"
        case .vaultExists(let path): "vault \(path) already exists"
        case .noVault(let path): "vault \(path) not found (run `keycask init`)"
        case .duplicateID(let id): "duplicate id \(id)"
        case .io(let why): why
        case .usage(let why): why
        case .failure(let why): why
        }
    }
}

Step 5: Run tests

Run: swift test --filter KeycaskErrorTests Expected: 2 tests pass.

Step 6: Commit

git add -A Sources/KeycaskCore Tests/KeycaskCoreTests
git commit -m "Add KeycaskError with exit codes"

Task 3: EntryID

Files:

Create: Sources/KeycaskCore/EntryID.swift
Create: Tests/KeycaskCoreTests/EntryIDTests.swift
Modify: Sources/KeycaskCore/KeycaskError.swift (duplicateID(EntryID))
Modify: Tests/KeycaskCoreTests/KeycaskErrorTests.swift

Interfaces:

Produces: public struct EntryID: Hashable, Sendable, Codable, CustomStringConvertible with static let alphabet: [Character], static let length = 8, let rawValue: String, init?(_ raw: String), static func random() -> EntryID, static func random(using: inout some RandomNumberGenerator) -> EntryID. Codable as a bare JSON string.
Step 1: Write the failing test

Tests/KeycaskCoreTests/EntryIDTests.swift:

import Foundation
import Testing

@testable import KeycaskCore

@Suite struct EntryIDTests {
    @Test func randomIDsHaveLengthEightFromTheAlphabet() {
        let allowed = Set(EntryID.alphabet)
        for _ in 0..<200 {
            let id = EntryID.random()
            #expect(id.rawValue.count == 8)
            #expect(id.rawValue.allSatisfy { allowed.contains($0) })
        }
    }

    @Test func alphabetExcludesAmbiguousCharacters() {
        let alphabet = Set(EntryID.alphabet)
        #expect(alphabet.count == 32)
        for bad in ["l", "o", "0", "1"] {
            #expect(!alphabet.contains(Character(bad)))
        }
    }

    @Test func parsingValidatesLengthAndAlphabet() {
        #expect(EntryID("abcd2345") != nil)
        #expect(EntryID("abcd234") == nil)
        #expect(EntryID("abcd23456") == nil)
        #expect(EntryID("abcd234l") == nil)
        #expect(EntryID("ABCD2345") == nil)
    }

    @Test func codableIsABareString() throws {
        let id = EntryID("abcd2345")!
        let data = try JSONEncoder().encode([id])
        #expect(String(decoding: data, as: UTF8.self) == "[\"abcd2345\"]")
        let back = try JSONDecoder().decode([EntryID].self, from: data)
        #expect(back == [id])
        #expect(throws: DecodingError.self) {
            try JSONDecoder().decode([EntryID].self, from: Data("[\"bad\"]".utf8))
        }
    }

    @Test func seededGeneratorIsDeterministic() {
        struct Counter: RandomNumberGenerator {
            var n: UInt64 = 0
            mutating func next() -> UInt64 {
                n += 1
                return n
            }
        }
        var a = Counter()
        var b = Counter()
        #expect(EntryID.random(using: &a) == EntryID.random(using: &b))
    }
}

Step 2: Run test to verify it fails

Run: swift test --filter EntryIDTests Expected: compile error, EntryID not found.

Step 3: Write the implementation

Sources/KeycaskCore/EntryID.swift:

public struct EntryID: Hashable, Sendable, CustomStringConvertible {
    public static let alphabet: [Character] = Array("abcdefghijkmnpqrstuvwxyz23456789")
    public static let length = 8

    public let rawValue: String

    public init?(_ raw: String) {
        guard raw.count == Self.length else { return nil }
        let allowed = Set(Self.alphabet)
        guard raw.allSatisfy({ allowed.contains($0) }) else { return nil }
        rawValue = raw
    }

    public static func random() -> EntryID {
        var rng = SystemRandomNumberGenerator()
        return random(using: &rng)
    }

    public static func random(using rng: inout some RandomNumberGenerator) -> EntryID {
        var chars: [Character] = []
        chars.reserveCapacity(length)
        for _ in 0..<length {
            chars.append(alphabet[Int(rng.next(upperBound: UInt32(alphabet.count)))])
        }
        return EntryID(String(chars))!
    }

    public var description: String { rawValue }
}

extension EntryID: Codable {
    public init(from decoder: any Decoder) throws {
        let raw = try decoder.singleValueContainer().decode(String.self)
        guard let id = EntryID(raw) else {
            throw DecodingError.dataCorrupted(
                .init(codingPath: decoder.codingPath, debugDescription: "invalid entry id \(raw)"))
        }
        self = id
    }

    public func encode(to encoder: any Encoder) throws {
        var container = encoder.singleValueContainer()
        try container.encode(rawValue)
    }
}

Step 4: Switch duplicateID to the real type

In KeycaskError.swift change case duplicateID(String) to case duplicateID(EntryID) and the message to "duplicate id \(id.rawValue)". In KeycaskErrorTests.swift change .duplicateID("abcd2345") to .duplicateID(EntryID("abcd2345")!).

Step 5: Run tests

Run: swift test --filter 'EntryIDTests|KeycaskErrorTests' Expected: 7 tests pass.

Step 6: Commit

git add Sources/KeycaskCore Tests/KeycaskCoreTests
git commit -m "Add EntryID"

Task 4: Entry

Files:

Create: Sources/KeycaskCore/Entry.swift
Create: Tests/KeycaskCoreTests/EntryTests.swift
Modify: Sources/KeycaskCore/KeycaskError.swift (ambiguous(name:candidates: [Entry]))
Modify: Tests/KeycaskCoreTests/KeycaskErrorTests.swift

Interfaces:

Consumes: EntryID.
Produces:

public struct Entry: Codable, Equatable, Sendable {
    public let id: EntryID
    public var name: String
    public var username: String?
    public var password: String
    public var url: String?
    public var notes: String?
    public var tags: [String]
    public let created: Date
    public var updated: Date

    public init(id: EntryID = .random(), name: String, username: String? = nil,
                password: String, url: String? = nil, notes: String? = nil,
                tags: [String] = [], now: Date = .now)
    public static func normalize(tags: [String]) -> [String]
    public static func truncateToSeconds(_ date: Date) -> Date
    public func hasTag(_ tag: String) -> Bool
    public func matches(_ query: String) -> Bool
}

Step 1: Write the failing test

Tests/KeycaskCoreTests/EntryTests.swift:

import Foundation
import Testing

@testable import KeycaskCore

@Suite struct EntryTests {
    @Test func initNormalizesTagsAndTruncatesDates() {
        let now = Date(timeIntervalSince1970: 1_700_000_000.75)
        let e = Entry(name: "gh", password: "p", tags: [" work", "Dev", "dev", "", "alpha"], now: now)
        #expect(e.tags == ["alpha", "Dev", "work"])
        #expect(e.created == Date(timeIntervalSince1970: 1_700_000_000))
        #expect(e.updated == e.created)
    }

    @Test func normalizeSortsCaseInsensitivelyAndKeepsFirstSpelling() {
        #expect(Entry.normalize(tags: ["b", "A", "a", "B"]) == ["A", "b"])
        #expect(Entry.normalize(tags: []) == [])
    }

    @Test func hasTagIsCaseInsensitive() {
        let e = Entry(name: "gh", password: "p", tags: ["Dev"])
        #expect(e.hasTag("dev"))
        #expect(e.hasTag("DEV"))
        #expect(!e.hasTag("ops"))
    }

    @Test func matchesSearchesEveryTextFieldExceptPassword() {
        let e = Entry(
            name: "GitHub", username: "cmc", password: "hunter2", url: "https://github.com",
            notes: "downtown office", tags: ["Dev"])
        #expect(e.matches("github"))
        #expect(e.matches("CMC"))
        #expect(e.matches("github.com"))
        #expect(e.matches("downtown"))
        #expect(e.matches("dev"))
        #expect(!e.matches("hunter2"))
        #expect(!e.matches("nothing"))
    }
}

Step 2: Run test to verify it fails

Run: swift test --filter EntryTests Expected: compile error, Entry not found.

Step 3: Write the implementation

Sources/KeycaskCore/Entry.swift:

import Foundation

public struct Entry: Codable, Equatable, Sendable {
    public let id: EntryID
    public var name: String
    public var username: String?
    public var password: String
    public var url: String?
    public var notes: String?
    public var tags: [String]
    public let created: Date
    public var updated: Date

    public init(
        id: EntryID = .random(),
        name: String,
        username: String? = nil,
        password: String,
        url: String? = nil,
        notes: String? = nil,
        tags: [String] = [],
        now: Date = .now
    ) {
        self.id = id
        self.name = name
        self.username = username
        self.password = password
        self.url = url
        self.notes = notes
        self.tags = Self.normalize(tags: tags)
        let stamp = Self.truncateToSeconds(now)
        created = stamp
        updated = stamp
    }

    public static func normalize(tags: [String]) -> [String] {
        var seen: Set<String> = []
        var out: [String] = []
        for raw in tags {
            let tag = raw.trimmingCharacters(in: .whitespaces)
            guard !tag.isEmpty, seen.insert(tag.lowercased()).inserted else { continue }
            out.append(tag)
        }
        return out.sorted { a, b in
            let (la, lb) = (a.lowercased(), b.lowercased())
            return la == lb ? a < b : la < lb
        }
    }

    public static func truncateToSeconds(_ date: Date) -> Date {
        Date(timeIntervalSince1970: date.timeIntervalSince1970.rounded(.down))
    }

    public func hasTag(_ tag: String) -> Bool {
        let needle = tag.lowercased()
        return tags.contains { $0.lowercased() == needle }
    }

    public func matches(_ query: String) -> Bool {
        let needle = query.lowercased()
        guard !needle.isEmpty else { return false }
        let haystacks = [name, username ?? "", url ?? "", notes ?? ""] + tags
        return haystacks.contains { $0.lowercased().contains(needle) }
    }
}

Step 4: Switch ambiguous to carry entries

In KeycaskError.swift change the case to case ambiguous(name: String, candidates: [Entry]) and the message body to:

case .ambiguous(let name, let candidates):
    (["\(name): ambiguous, use an id:"]
        + candidates.map { "  \($0.id.rawValue)  \($0.username ?? "")  \($0.url ?? "")" })
        .joined(separator: "\n")

KeycaskErrorTests.swift already passes candidates: [], which now infers [Entry]. Add one test there:

@Test func ambiguousListsCandidateIDs() {
    let a = Entry(id: EntryID("aaaa2222")!, name: "gh", username: "one", password: "p")
    let b = Entry(id: EntryID("bbbb3333")!, name: "gh", password: "p", url: "https://x")
    let m = KeycaskError.ambiguous(name: "gh", candidates: [a, b]).message
    #expect(m.hasPrefix("gh: ambiguous, use an id:\n"))
    #expect(m.contains("aaaa2222"))
    #expect(m.contains("bbbb3333"))
    #expect(m.contains("https://x"))
}

Step 5: Run tests

Run: swift test --filter 'EntryTests|KeycaskErrorTests' Expected: all pass.

Step 6: Commit

git add Sources/KeycaskCore Tests/KeycaskCoreTests
git commit -m "Add Entry with tag normalization and search"

Task 5: Vault and VaultCodec

Files:

Create: Sources/KeycaskCore/Vault.swift
Create: Sources/KeycaskCore/VaultCodec.swift
Create: Tests/KeycaskCoreTests/VaultTests.swift
Create: Tests/KeycaskCoreTests/VaultCodecTests.swift

Interfaces:

Consumes: Entry, EntryID, KeycaskError.
Produces:

public struct Vault: Codable, Equatable, Sendable {
    public var entries: [Entry]
    public init(entries: [Entry] = [])
    public func entry(id: EntryID) -> Entry?
    public mutating func add(_ entry: Entry) throws            // duplicateID
    public mutating func remove(id: EntryID) throws            // notFound(id)
    public mutating func update(id: EntryID, now: Date = .now,
                                _ change: (inout Entry) -> Void) throws  // notFound(id); normalizes tags, sets updated
    public func resolve(_ ref: String) throws -> Entry         // id, unique name, ambiguous, notFound
    public func filter(tag: String) -> [Entry]
    public func search(_ query: String) -> [Entry]
    public var sortedEntries: [Entry]                          // by name (case-insensitive), then id
}

public enum VaultCodec {
    public static func encode(_ vault: Vault) throws -> Data   // sortedKeys, iso8601; io on failure
    public static func decode(_ data: Data) throws -> Vault    // corrupt on failure
    public static func makeEncoder() -> JSONEncoder            // shared settings, also used by CLI output
}

Step 1: Write the failing tests

Tests/KeycaskCoreTests/VaultTests.swift:

import Foundation
import Testing

@testable import KeycaskCore

@Suite struct VaultTests {
    func idA() -> EntryID { EntryID("aaaa2222")! }
    func idB() -> EntryID { EntryID("bbbb3333")! }

    @Test func addRejectsDuplicateID() throws {
        var v = Vault()
        try v.add(Entry(id: idA(), name: "gh", password: "p"))
        #expect(throws: KeycaskError.duplicateID(idA())) {
            try v.add(Entry(id: idA(), name: "other", password: "p"))
        }
        #expect(v.entries.count == 1)
    }

    @Test func removeUnknownIsNotFound() {
        var v = Vault()
        #expect(throws: KeycaskError.notFound("aaaa2222")) { try v.remove(id: idA()) }
    }

    @Test func updateSetsUpdatedAndNormalizesTags() throws {
        let t0 = Date(timeIntervalSince1970: 1_000)
        let t1 = Date(timeIntervalSince1970: 2_000.9)
        var v = Vault()
        try v.add(Entry(id: idA(), name: "gh", password: "p", now: t0))
        try v.update(id: idA(), now: t1) { e in
            e.tags = ["z", "A", "a"]
            e.password = "q"
        }
        let e = v.entry(id: idA())!
        #expect(e.password == "q")
        #expect(e.tags == ["A", "z"])
        #expect(e.created == t0)
        #expect(e.updated == Date(timeIntervalSince1970: 2_000))
    }

    @Test func resolvePrefersIDThenUniqueName() throws {
        var v = Vault()
        try v.add(Entry(id: idA(), name: "gh", password: "p"))
        try v.add(Entry(id: idB(), name: "aaaa2222", password: "p"))
        #expect(try v.resolve("aaaa2222").id == idA())
        #expect(try v.resolve("gh").id == idA())
        #expect(try v.resolve("bbbb3333").id == idB())
    }

    @Test func resolveReportsAmbiguousWithAllCandidates() throws {
        var v = Vault()
        let a = Entry(id: idA(), name: "gh", password: "p")
        let b = Entry(id: idB(), name: "gh", password: "p")
        try v.add(a)
        try v.add(b)
        #expect(throws: KeycaskError.ambiguous(name: "gh", candidates: [a, b])) {
            try v.resolve("gh")
        }
    }

    @Test func resolveUnknownIsNotFound() {
        #expect(throws: KeycaskError.notFound("nope")) { try Vault().resolve("nope") }
    }

    @Test func filterAndSearch() throws {
        var v = Vault()
        try v.add(Entry(id: idA(), name: "GitHub", password: "p", tags: ["dev"]))
        try v.add(Entry(id: idB(), name: "bank", password: "p", url: "https://bank.example"))
        #expect(v.filter(tag: "DEV").map(\.id) == [idA()])
        #expect(v.search("example").map(\.id) == [idB()])
        #expect(v.search("zzz").isEmpty)
    }

    @Test func sortedEntriesOrderByNameThenID() throws {
        var v = Vault()
        try v.add(Entry(id: idB(), name: "gh", password: "p"))
        try v.add(Entry(id: idA(), name: "gh", password: "p"))
        try v.add(Entry(id: EntryID("cccc4444")!, name: "Alpha", password: "p"))
        #expect(v.sortedEntries.map(\.id.rawValue) == ["cccc4444", "aaaa2222", "bbbb3333"])
    }
}

Tests/KeycaskCoreTests/VaultCodecTests.swift:

import Foundation
import Testing

@testable import KeycaskCore

@Suite struct VaultCodecTests {
    @Test func roundTripsAndIsDeterministic() throws {
        var v = Vault()
        try v.add(
            Entry(
                id: EntryID("aaaa2222")!, name: "gh", username: "cmc", password: "p",
                url: "https://github.com", notes: "n", tags: ["dev"],
                now: Date(timeIntervalSince1970: 1_700_000_000)))
        let a = try VaultCodec.encode(v)
        let b = try VaultCodec.encode(v)
        #expect(a == b)
        #expect(try VaultCodec.decode(a) == v)
    }

    @Test func datesAreISO8601WholeSeconds() throws {
        var v = Vault()
        try v.add(
            Entry(id: EntryID("aaaa2222")!, name: "gh", password: "p",
                  now: Date(timeIntervalSince1970: 1_700_000_000)))
        let text = String(decoding: try VaultCodec.encode(v), as: UTF8.self)
        #expect(text.contains("\"created\":\"2023-11-14T22:13:20Z\""))
    }

    @Test func keysAreSorted() throws {
        var v = Vault()
        try v.add(Entry(id: EntryID("aaaa2222")!, name: "gh", password: "p"))
        let text = String(decoding: try VaultCodec.encode(v), as: UTF8.self)
        let created = text.range(of: "\"created\"")!.lowerBound
        let id = text.range(of: "\"id\"")!.lowerBound
        let updated = text.range(of: "\"updated\"")!.lowerBound
        #expect(created < id && id < updated)
    }

    @Test func garbageIsCorrupt() {
        #expect(throws: KeycaskError.self) { try VaultCodec.decode(Data("nope".utf8)) }
        do {
            _ = try VaultCodec.decode(Data("{\"entries\":[{\"id\":1}]}".utf8))
            Issue.record("expected corrupt")
        } catch let e as KeycaskError {
            #expect(e.exitCode == 1)
            #expect(e.message.hasPrefix("vault is corrupt:"))
        } catch {
            Issue.record("wrong error \(error)")
        }
    }
}

Step 2: Run tests to verify they fail

Run: swift test --filter 'VaultTests|VaultCodecTests' Expected: compile error, Vault not found.

Step 3: Write Vault.swift

import Foundation

public struct Vault: Codable, Equatable, Sendable {
    public var entries: [Entry]

    public init(entries: [Entry] = []) {
        self.entries = entries
    }

    public func entry(id: EntryID) -> Entry? {
        entries.first { $0.id == id }
    }

    public mutating func add(_ entry: Entry) throws {
        guard self.entry(id: entry.id) == nil else { throw KeycaskError.duplicateID(entry.id) }
        entries.append(entry)
    }

    public mutating func remove(id: EntryID) throws {
        guard let index = entries.firstIndex(where: { $0.id == id }) else {
            throw KeycaskError.notFound(id.rawValue)
        }
        entries.remove(at: index)
    }

    public mutating func update(
        id: EntryID, now: Date = .now, _ change: (inout Entry) -> Void
    ) throws {
        guard let index = entries.firstIndex(where: { $0.id == id }) else {
            throw KeycaskError.notFound(id.rawValue)
        }
        change(&entries[index])
        entries[index].tags = Entry.normalize(tags: entries[index].tags)
        entries[index].updated = Entry.truncateToSeconds(now)
    }

    public func resolve(_ ref: String) throws -> Entry {
        if let id = EntryID(ref), let hit = entry(id: id) {
            return hit
        }
        let byName = entries.filter { $0.name == ref }
        switch byName.count {
        case 0: throw KeycaskError.notFound(ref)
        case 1: return byName[0]
        default: throw KeycaskError.ambiguous(name: ref, candidates: byName)
        }
    }

    public func filter(tag: String) -> [Entry] {
        sortedEntries.filter { $0.hasTag(tag) }
    }

    public func search(_ query: String) -> [Entry] {
        sortedEntries.filter { $0.matches(query) }
    }

    public var sortedEntries: [Entry] {
        entries.sorted { a, b in
            let (la, lb) = (a.name.lowercased(), b.name.lowercased())
            return la == lb ? a.id.rawValue < b.id.rawValue : la < lb
        }
    }
}

Step 4: Write VaultCodec.swift

import Foundation

public enum VaultCodec {
    public static func makeEncoder() -> JSONEncoder {
        let encoder = JSONEncoder()
        encoder.outputFormatting = [.sortedKeys, .withoutEscapingSlashes]
        encoder.dateEncodingStrategy = .iso8601
        return encoder
    }

    public static func makeDecoder() -> JSONDecoder {
        let decoder = JSONDecoder()
        decoder.dateDecodingStrategy = .iso8601
        return decoder
    }

    public static func encode(_ vault: Vault) throws -> Data {
        do {
            return try makeEncoder().encode(vault)
        } catch {
            throw KeycaskError.io("encode vault: \(error)")
        }
    }

    public static func decode(_ data: Data) throws -> Vault {
        do {
            return try makeDecoder().decode(Vault.self, from: data)
        } catch {
            throw KeycaskError.corrupt("\(error)")
        }
    }
}

Step 5: Run tests

Run: swift test --filter 'VaultTests|VaultCodecTests' Expected: 12 tests pass.

Step 6: Commit

git add Sources/KeycaskCore Tests/KeycaskCoreTests
git commit -m "Add Vault operations and deterministic JSON codec"

Task 6: Generator and word list

Files:

Create: Sources/KeycaskCore/Wordlist.swift (generated)
Create: Sources/KeycaskCore/Generator.swift
Create: NOTICE
Create: Tests/KeycaskCoreTests/GeneratorTests.swift

Interfaces:

Produces:

public enum Wordlist { public static let words: [String] }   // 7776 entries
public enum Generator {
    public static let alphabet: [Character]  // A-Z a-z 0-9 and !@#$%^&*()-_=+[]{};:,.<>?
    public static let defaultLength = 24
    public static let wordSeparator = "-"
    public static func password(length: Int) -> String
    public static func password(length: Int, using: inout some RandomNumberGenerator) -> String
    public static func passphrase(words: Int) -> String
    public static func passphrase(words: Int, using: inout some RandomNumberGenerator) -> String
}

Step 1: Generate Wordlist.swift from the EFF list

cd /Users/cmc/git/krz/keycask
curl -fsSL https://www.eff.org/files/2016/07/18/eff_large_wordlist.txt -o /tmp/eff.txt
test "$(wc -l < /tmp/eff.txt)" -eq 7776
{
  printf '// EFF long word list, https://www.eff.org/dice. See NOTICE.\n'
  printf 'let effLongWordlist = """\n'
  cut -f2 /tmp/eff.txt
  printf '"""\n\npublic enum Wordlist {\n'
  printf '    public static let words: [String] = effLongWordlist.split(separator: "\\n").map(String.init)\n'
  printf '}\n'
} > Sources/KeycaskCore/Wordlist.swift
rm /tmp/eff.txt

Step 2: Write NOTICE

The word list in Sources/KeycaskCore/Wordlist.swift is the EFF Long
Wordlist by the Electronic Frontier Foundation, licensed under the
Creative Commons Attribution 3.0 United States License.
https://www.eff.org/dice
https://creativecommons.org/licenses/by/3.0/us/

Step 3: Write the failing test

Tests/KeycaskCoreTests/GeneratorTests.swift:

import Testing

@testable import KeycaskCore

@Suite struct GeneratorTests {
    struct Counter: RandomNumberGenerator {
        var n: UInt64 = 0
        mutating func next() -> UInt64 {
            n &+= 0x9E37_79B9_7F4A_7C15
            return n
        }
    }

    @Test func wordlistHas7776UniqueWords() {
        #expect(Wordlist.words.count == 7776)
        #expect(Set(Wordlist.words).count == 7776)
        #expect(Wordlist.words.first == "abacus")
        #expect(Wordlist.words.allSatisfy { !$0.isEmpty && !$0.contains(" ") })
    }

    @Test func passwordHasRequestedLengthFromTheAlphabet() {
        let allowed = Set(Generator.alphabet)
        for length in [1, 8, 24, 64] {
            let p = Generator.password(length: length)
            #expect(p.count == length)
            #expect(p.allSatisfy { allowed.contains($0) })
        }
        #expect(Generator.password(length: 0) == "")
    }

    @Test func alphabetCoversAllClasses() {
        let s = String(Generator.alphabet)
        #expect(s.contains("A") && s.contains("z") && s.contains("7") && s.contains("!"))
        #expect(Set(Generator.alphabet).count == Generator.alphabet.count)
    }

    @Test func passphraseUsesWordsFromTheList() {
        let words = Set(Wordlist.words)
        let p = Generator.passphrase(words: 5)
        let parts = p.split(separator: "-").map(String.init)
        #expect(parts.count == 5)
        #expect(parts.allSatisfy { words.contains($0) })
        #expect(Generator.passphrase(words: 0) == "")
    }

    @Test func seededOutputIsReproducible() {
        var a = Counter()
        var b = Counter()
        #expect(Generator.password(length: 16, using: &a) == Generator.password(length: 16, using: &b))
        #expect(Generator.passphrase(words: 3, using: &a) == Generator.passphrase(words: 3, using: &b))
    }
}

Step 4: Run test to verify it fails

Run: swift test --filter GeneratorTests Expected: compile error, Generator not found.

Step 5: Write Generator.swift

public enum Generator {
    public static let alphabet: [Character] = Array(
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()-_=+[]{};:,.<>?"
    )
    public static let defaultLength = 24
    public static let wordSeparator = "-"

    public static func password(length: Int) -> String {
        var rng = SystemRandomNumberGenerator()
        return password(length: length, using: &rng)
    }

    public static func password(length: Int, using rng: inout some RandomNumberGenerator) -> String {
        var chars: [Character] = []
        chars.reserveCapacity(max(length, 0))
        for _ in 0..<max(length, 0) {
            chars.append(alphabet[Int(rng.next(upperBound: UInt32(alphabet.count)))])
        }
        return String(chars)
    }

    public static func passphrase(words: Int) -> String {
        var rng = SystemRandomNumberGenerator()
        return passphrase(words: words, using: &rng)
    }

    public static func passphrase(words: Int, using rng: inout some RandomNumberGenerator) -> String {
        let list = Wordlist.words
        var picked: [String] = []
        for _ in 0..<max(words, 0) {
            picked.append(list[Int(rng.next(upperBound: UInt32(list.count)))])
        }
        return picked.joined(separator: wordSeparator)
    }
}

Step 6: Run tests and lint

Run: swift test --filter GeneratorTests && swift format lint --strict --recursive Sources Tests Expected: 5 tests pass. If the linter complains about the long string literal in Wordlist.swift, add "// swift-format-ignore-file" as its first line.

Step 7: Commit

git add NOTICE Sources/KeycaskCore Tests/KeycaskCoreTests
git commit -m "Add password and passphrase generator with EFF word list"

Task 7: Envelope

Files:

Create: Sources/KeycaskCore/Envelope.swift
Create: Tests/KeycaskCoreTests/EnvelopeTests.swift

Interfaces:

Consumes: KeycaskError.
Produces:

public struct Envelope: Codable, Equatable, Sendable {
    public struct KDFParams: Codable, Equatable, Sendable {
        public var name: String
        public var iterations: Int
        public var salt: Data
        public init(name: String, iterations: Int, salt: Data)
        public static func fresh(iterations: Int = Envelope.defaultIterations) -> KDFParams
    }
    public static let currentFormat = 1
    public static let defaultIterations = 600_000
    public static let kdfName = "pbkdf2-hmac-sha256"
    public static let saltLength = 16
    public var format: Int
    public var kdf: KDFParams
    public var box: Data

    public static func seal(_ plaintext: Data, passphrase: String, kdf: KDFParams) throws -> Envelope
    public func open(passphrase: String) throws -> Data       // cannotDecrypt / corrupt
    public init(parsing data: Data) throws                     // corrupt
    public func encoded() throws -> Data
    static func deriveKey(passphrase: String, kdf: KDFParams) throws -> SymmetricKey
}

Step 1: Write the failing test

Tests/KeycaskCoreTests/EnvelopeTests.swift:

import Crypto
import Foundation
import Testing

@testable import KeycaskCore

@Suite struct EnvelopeTests {
    // Low iteration count keeps the suite fast. Production uses Envelope.defaultIterations.
    let kdf = Envelope.KDFParams(
        name: Envelope.kdfName, iterations: 1_000, salt: Data(repeating: 7, count: 16))

    func hex(_ key: SymmetricKey) -> String {
        key.withUnsafeBytes { $0.map { String(format: "%02x", $0) }.joined() }
    }

    @Test func pbkdf2MatchesPublishedVectors() throws {
        let one = Envelope.KDFParams(name: Envelope.kdfName, iterations: 1, salt: Data("salt".utf8))
        #expect(
            hex(try Envelope.deriveKey(passphrase: "password", kdf: one))
                == "120fb6cffcf8b32c43e7225256c4f837a86548c92ccc35480805987cb70be17b")
        let many = Envelope.KDFParams(name: Envelope.kdfName, iterations: 4096, salt: Data("salt".utf8))
        #expect(
            hex(try Envelope.deriveKey(passphrase: "password", kdf: many))
                == "c5e478d59288c841aa530db6845c4c8d962893a001ce4e11a4963873aa98134a")
    }

    @Test func sealThenOpenRoundTrips() throws {
        let env = try Envelope.seal(Data("hello vault".utf8), passphrase: "pw", kdf: kdf)
        #expect(env.format == 1)
        #expect(env.kdf == kdf)
        #expect(try env.open(passphrase: "pw") == Data("hello vault".utf8))
    }

    @Test func wrongPassphraseCannotDecrypt() throws {
        let env = try Envelope.seal(Data("x".utf8), passphrase: "pw", kdf: kdf)
        #expect(throws: KeycaskError.cannotDecrypt) { try env.open(passphrase: "PW") }
    }

    @Test func tamperedBoxCannotDecrypt() throws {
        var env = try Envelope.seal(Data("x".utf8), passphrase: "pw", kdf: kdf)
        env.box[env.box.count - 1] ^= 0x01
        #expect(throws: KeycaskError.cannotDecrypt) { try env.open(passphrase: "pw") }
    }

    @Test func nonceIsFreshAndSaltIsKept() throws {
        let a = try Envelope.seal(Data("x".utf8), passphrase: "pw", kdf: kdf)
        let b = try Envelope.seal(Data("x".utf8), passphrase: "pw", kdf: kdf)
        #expect(a.box != b.box)
        #expect(a.kdf.salt == b.kdf.salt)
    }

    @Test func freshParamsUseDefaults() {
        let p = Envelope.KDFParams.fresh()
        #expect(p.name == "pbkdf2-hmac-sha256")
        #expect(p.iterations == 600_000)
        #expect(p.salt.count == 16)
        #expect(p.salt != Envelope.KDFParams.fresh().salt)
    }

    @Test func encodedShapeMatchesTheSpec() throws {
        let env = try Envelope.seal(Data("x".utf8), passphrase: "pw", kdf: kdf)
        let json = try JSONSerialization.jsonObject(with: env.encoded()) as! [String: Any]
        #expect(json["format"] as? Int == 1)
        let k = json["kdf"] as! [String: Any]
        #expect(k["name"] as? String == "pbkdf2-hmac-sha256")
        #expect(k["iterations"] as? Int == 1_000)
        #expect(Data(base64Encoded: k["salt"] as! String) == kdf.salt)
        #expect(Data(base64Encoded: json["box"] as! String) == env.box)
        #expect(try Envelope(parsing: env.encoded()) == env)
    }

    @Test func malformedInputsAreCorrupt() throws {
        #expect(throws: KeycaskError.self) { try Envelope(parsing: Data("not json".utf8)) }
        #expect(throws: KeycaskError.self) { try Envelope(parsing: Data("{\"format\":1}".utf8)) }

        var wrongFormat = try Envelope.seal(Data("x".utf8), passphrase: "pw", kdf: kdf)
        wrongFormat.format = 2
        #expect(throws: KeycaskError.corrupt("unsupported format 2")) {
            try wrongFormat.open(passphrase: "pw")
        }

        var wrongKDF = try Envelope.seal(Data("x".utf8), passphrase: "pw", kdf: kdf)
        wrongKDF.kdf.name = "argon2id"
        #expect(throws: KeycaskError.corrupt("unsupported kdf argon2id")) {
            try wrongKDF.open(passphrase: "pw")
        }

        var shortBox = try Envelope.seal(Data("x".utf8), passphrase: "pw", kdf: kdf)
        shortBox.box = Data([1, 2, 3])
        #expect(throws: KeycaskError.corrupt("box too short")) { try shortBox.open(passphrase: "pw") }
    }

    @Test func passphraseIsNFCNormalized() throws {
        let composed = "caf\u{00E9}"
        let decomposed = "cafe\u{0301}"
        let env = try Envelope.seal(Data("x".utf8), passphrase: composed, kdf: kdf)
        #expect(try env.open(passphrase: decomposed) == Data("x".utf8))
    }
}

Step 2: Run test to verify it fails

Run: swift test --filter EnvelopeTests Expected: compile error, Envelope not found.

Step 3: Write Envelope.swift

import Crypto
import Foundation
import _CryptoExtras

public struct Envelope: Codable, Equatable, Sendable {
    public struct KDFParams: Codable, Equatable, Sendable {
        public var name: String
        public var iterations: Int
        public var salt: Data

        public init(name: String, iterations: Int, salt: Data) {
            self.name = name
            self.iterations = iterations
            self.salt = salt
        }

        public static func fresh(iterations: Int = Envelope.defaultIterations) -> KDFParams {
            var rng = SystemRandomNumberGenerator()
            let salt = Data((0..<Envelope.saltLength).map { _ in UInt8.random(in: .min ... .max, using: &rng) })
            return KDFParams(name: Envelope.kdfName, iterations: iterations, salt: salt)
        }
    }

    public static let currentFormat = 1
    public static let defaultIterations = 600_000
    public static let kdfName = "pbkdf2-hmac-sha256"
    public static let saltLength = 16
    static let keyLength = 32
    static let minimumBoxLength = 12 + 16

    public var format: Int
    public var kdf: KDFParams
    public var box: Data

    public static func seal(_ plaintext: Data, passphrase: String, kdf: KDFParams) throws -> Envelope {
        let key = try deriveKey(passphrase: passphrase, kdf: kdf)
        do {
            let sealed = try ChaChaPoly.seal(plaintext, using: key)
            return Envelope(format: currentFormat, kdf: kdf, box: sealed.combined)
        } catch {
            throw KeycaskError.failure("encrypt: \(error)")
        }
    }

    public func open(passphrase: String) throws -> Data {
        guard format == Self.currentFormat else {
            throw KeycaskError.corrupt("unsupported format \(format)")
        }
        guard kdf.name == Self.kdfName else {
            throw KeycaskError.corrupt("unsupported kdf \(kdf.name)")
        }
        guard box.count >= Self.minimumBoxLength else {
            throw KeycaskError.corrupt("box too short")
        }
        let key = try Self.deriveKey(passphrase: passphrase, kdf: kdf)
        let sealed: ChaChaPoly.SealedBox
        do {
            sealed = try ChaChaPoly.SealedBox(combined: box)
        } catch {
            throw KeycaskError.corrupt("box is malformed")
        }
        do {
            return try ChaChaPoly.open(sealed, using: key)
        } catch {
            throw KeycaskError.cannotDecrypt
        }
    }

    public init(parsing data: Data) throws {
        do {
            self = try JSONDecoder().decode(Envelope.self, from: data)
        } catch {
            throw KeycaskError.corrupt("not a keycask vault: \(error)")
        }
    }

    public func encoded() throws -> Data {
        let encoder = JSONEncoder()
        encoder.outputFormatting = [.sortedKeys, .prettyPrinted]
        do {
            return try encoder.encode(self)
        } catch {
            throw KeycaskError.io("encode envelope: \(error)")
        }
    }

    init(format: Int, kdf: KDFParams, box: Data) {
        self.format = format
        self.kdf = kdf
        self.box = box
    }

    static func deriveKey(passphrase: String, kdf: KDFParams) throws -> SymmetricKey {
        let normalized = Array(passphrase.precomposedStringWithCanonicalMapping.utf8)
        do {
            return try KDF.Insecure.PBKDF2.deriveKey(
                from: normalized, salt: kdf.salt, using: .sha256,
                outputByteCount: keyLength, unsafeUncheckedRounds: kdf.iterations)
        } catch {
            throw KeycaskError.failure("derive key: \(error)")
        }
    }
}

unsafeUncheckedRounds is used because the checked overload rejects fewer than 210000 rounds, and the vault decides the count. KDFParams.fresh() always produces 600000.

Step 4: Run tests

Run: swift test --filter EnvelopeTests Expected: 9 tests pass.

Step 5: Commit

git add Sources/KeycaskCore Tests/KeycaskCoreTests
git commit -m "Add passphrase-encrypted vault envelope"

Task 8: Core merge request

Files: none new.

Step 1: Full suite and lint

Run: swift test && swift format lint --strict --recursive Sources Tests Package.swift Expected: all pass, no lint output.

Step 2: Push and open the MR

git push -u origin core
gitbay mr create --source core --target main --title "Core library: model, envelope, generator" --file - <<'EOF'
KeycaskCore: Entry, EntryID, Vault, VaultCodec, Envelope, Generator, Wordlist, KeycaskError.
Package scaffold and gitbay CI.
EOF

Step 3: Wait for CI, merge, clean up

Run gitbay build list --json until the build for core is green. Then:

gitbay mr merge <n> --strategy squash
git switch main && git pull && git branch -D core && git push origin --delete core

If the CI job fails on the swiftly install lines, read gitbay build log <n>, fix .gitbay/ci.yml on the branch, push, and re-check. Do not merge red.

Task 9: CLI skeleton, paths, passphrase, atomic write, `init`

Files:

Create: Sources/keycask/main.swift (replace)
Create: Sources/keycask/Keycask.swift
Create: Sources/keycask/Paths.swift
Create: Sources/keycask/Terminal.swift
Create: Sources/keycask/Passphrase.swift
Create: Sources/keycask/AtomicFile.swift
Create: Sources/keycask/OpenVault.swift
Create: Sources/keycask/Commands/Init.swift
Modify: Tests/KeycaskCLITests/CLI.swift
Create: Tests/KeycaskCLITests/InitTests.swift
Create: Tests/KeycaskCLITests/PathsTests.swift

Interfaces:

Consumes: Vault, VaultCodec, Envelope, KeycaskError.
Produces:

struct GlobalOptions: ParsableArguments { var vault: String? }
enum Paths { static func vaultURL(override: String?, environment: [String: String]) -> URL }
enum Terminal {
    static var stdinIsTTY: Bool
    static func readSecretLine(prompt: String) throws -> String
    static func readLine(prompt: String) -> String?
    static func confirm(_ question: String) -> Bool
}
enum Passphrase {
    static let variable = "KEYCASK_PASSPHRASE"
    static func obtain(confirm: Bool, environment: [String: String]) throws -> String
}
enum AtomicFile { static func write(_ data: Data, to url: URL) throws }
struct OpenVault {
    var vault: Vault
    let kdf: Envelope.KDFParams
    let url: URL
    let passphrase: String
    static func load(_ options: GlobalOptions) throws -> OpenVault
    static func create(_ options: GlobalOptions) throws -> URL
    func save() throws
}
struct CLI {   // test harness
    struct Result { let status: Int32; let stdout: String; let stderr: String }
    let dir: URL; let vault: URL; static let passphrase = "correct horse battery"
    init() throws
    func run(_ args: [String], stdin: String? = nil, passphrase: String? = CLI.passphrase,
             extraEnvironment: [String: String] = [:]) throws -> Result
}

Step 1: Create the branch

git switch -c cli

Step 2: Extend the test harness

Replace Tests/KeycaskCLITests/CLI.swift:

import Foundation
import Testing

enum Binary {
    static let url: URL = {
        #if os(macOS)
            for bundle in Bundle.allBundles where bundle.bundlePath.hasSuffix(".xctest") {
                return bundle.bundleURL.deletingLastPathComponent().appendingPathComponent("keycask")
            }
            fatalError("test bundle not found")
        #elseif os(Windows)
            return Bundle.main.bundleURL.appendingPathComponent("keycask.exe")
        #else
            return Bundle.main.bundleURL.appendingPathComponent("keycask")
        #endif
    }()
}

struct CLI {
    struct Result {
        let status: Int32
        let stdout: String
        let stderr: String
        var lines: [String] { stdout.split(separator: "\n").map(String.init) }
    }

    static let passphrase = "correct horse battery"

    let dir: URL
    let vault: URL

    init() throws {
        dir = FileManager.default.temporaryDirectory
            .appendingPathComponent("keycask-tests-\(UUID().uuidString)")
        try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
        vault = dir.appendingPathComponent("vault.kc")
    }

    @discardableResult
    func run(
        _ args: [String],
        stdin: String? = nil,
        passphrase: String? = CLI.passphrase,
        extraEnvironment: [String: String] = [:]
    ) throws -> Result {
        let process = Process()
        process.executableURL = Binary.url
        process.arguments = args
        var env = ProcessInfo.processInfo.environment
        env["KEYCASK_VAULT"] = vault.path
        env.removeValue(forKey: "KEYCASK_PASSPHRASE")
        if let passphrase { env["KEYCASK_PASSPHRASE"] = passphrase }
        for (k, v) in extraEnvironment { env[k] = v }
        process.environment = env

        let out = Pipe()
        let err = Pipe()
        let input = Pipe()
        process.standardOutput = out
        process.standardError = err
        process.standardInput = input
        try process.run()
        if let stdin {
            input.fileHandleForWriting.write(Data(stdin.utf8))
        }
        try input.fileHandleForWriting.close()
        let outData = out.fileHandleForReading.readDataToEndOfFile()
        let errData = err.fileHandleForReading.readDataToEndOfFile()
        process.waitUntilExit()
        return Result(
            status: process.terminationStatus,
            stdout: String(decoding: outData, as: UTF8.self),
            stderr: String(decoding: errData, as: UTF8.self))
    }

    /// Runs `init` and returns the harness, for tests that need a vault.
    static func initialized() throws -> CLI {
        let cli = try CLI()
        let r = try cli.run(["init"])
        precondition(r.status == 0, "init failed: \(r.stderr)")
        return cli
    }
}

Remove the binaryIsBuilt test from this file; the harness replaces it.

Step 3: Write the failing tests

Tests/KeycaskCLITests/InitTests.swift:

import Foundation
import Testing

@Suite struct InitTests {
    @Test func initCreatesVaultAndPrintsPath() throws {
        let cli = try CLI()
        let r = try cli.run(["init"])
        #expect(r.status == 0)
        #expect(r.stdout.contains(cli.vault.path))
        #expect(FileManager.default.fileExists(atPath: cli.vault.path))
        let text = try String(contentsOf: cli.vault, encoding: .utf8)
        #expect(text.contains("\"format\" : 1"))
        #expect(text.contains("pbkdf2-hmac-sha256"))
        #expect(!text.contains("entries"))
    }

    @Test func initRefusesExistingVault() throws {
        let cli = try CLI.initialized()
        let r = try cli.run(["init"])
        #expect(r.status == 1)
        #expect(r.stderr.contains("already exists"))
    }

    @Test func initWithoutPassphraseOrTTYIsUsageError() throws {
        let cli = try CLI()
        let r = try cli.run(["init"], passphrase: nil)
        #expect(r.status == 2)
        #expect(r.stderr.contains("KEYCASK_PASSPHRASE"))
    }

    @Test func emptyPassphraseIsRejected() throws {
        let cli = try CLI()
        let r = try cli.run(["init"], passphrase: "")
        #expect(r.status == 1)
        #expect(r.stderr.contains("empty"))
    }

    @Test func vaultFlagBeatsEnvironment() throws {
        let cli = try CLI()
        let other = cli.dir.appendingPathComponent("elsewhere.kc")
        let r = try cli.run(["--vault", other.path, "init"])
        #expect(r.status == 0)
        #expect(FileManager.default.fileExists(atPath: other.path))
        #expect(!FileManager.default.fileExists(atPath: cli.vault.path))
    }

    @Test func unknownSubcommandIsUsageError() throws {
        let cli = try CLI()
        let r = try cli.run(["frobnicate"])
        #expect(r.status == 2)
        #expect(r.stderr.contains("Usage"))
    }

    @Test func helpExitsZero() throws {
        let cli = try CLI()
        let r = try cli.run(["--help"])
        #expect(r.status == 0)
        #expect(r.stdout.contains("init"))
    }

    #if !os(Windows)
        @Test func vaultIsPrivateOnUnix() throws {
            let cli = try CLI.initialized()
            let attrs = try FileManager.default.attributesOfItem(atPath: cli.vault.path)
            let mode = (attrs[.posixPermissions] as! NSNumber).intValue & 0o777
            #expect(mode == 0o600)
        }
    #endif

    @Test func noTempFileLeftBehind() throws {
        let cli = try CLI.initialized()
        let names = try FileManager.default.contentsOfDirectory(atPath: cli.dir.path)
        #expect(names == ["vault.kc"])
    }
}

Tests/KeycaskCLITests/PathsTests.swift tests Paths in process. It needs @testable import keycask, which works because the test target depends on the executable target:

import Foundation
import Testing

@testable import keycask

@Suite struct PathsTests {
    @Test func overrideWinsOverEverything() {
        let url = Paths.vaultURL(
            override: "/x/v.kc", environment: ["KEYCASK_VAULT": "/y", "HOME": "/h"])
        #expect(url.path == "/x/v.kc")
    }

    @Test func environmentVariableWinsOverDefaults() {
        let url = Paths.vaultURL(override: nil, environment: ["KEYCASK_VAULT": "/y/v.kc", "HOME": "/h"])
        #expect(url.path == "/y/v.kc")
    }

    #if os(Windows)
        @Test func windowsUsesLocalAppData() {
            let url = Paths.vaultURL(override: nil, environment: ["LOCALAPPDATA": "C:\\Users\\u\\AppData\\Local"])
            #expect(url.path.hasSuffix("keycask/vault.kc") || url.path.hasSuffix("keycask\\vault.kc"))
        }
    #else
        @Test func xdgDataHomeIsUsedWhenSet() {
            let url = Paths.vaultURL(override: nil, environment: ["XDG_DATA_HOME": "/d", "HOME": "/h"])
            #expect(url.path == "/d/keycask/vault.kc")
        }

        @Test func homeFallback() {
            let url = Paths.vaultURL(override: nil, environment: ["HOME": "/h"])
            #expect(url.path == "/h/.local/share/keycask/vault.kc")
        }
    #endif
}

Step 4: Run tests to verify they fail

Run: swift test --filter 'InitTests|PathsTests' Expected: compile error, Paths not found.

Step 5: Write Paths.swift

import Foundation

enum Paths {
    static let variable = "KEYCASK_VAULT"

    static func vaultURL(
        override: String?, environment: [String: String] = ProcessInfo.processInfo.environment
    ) -> URL {
        if let override { return URL(fileURLWithPath: override) }
        if let env = environment[variable], !env.isEmpty { return URL(fileURLWithPath: env) }
        return defaultDirectory(environment: environment)
            .appendingPathComponent("keycask").appendingPathComponent("vault.kc")
    }

    private static func defaultDirectory(environment: [String: String]) -> URL {
        #if os(Windows)
            let base = environment["LOCALAPPDATA"] ?? environment["USERPROFILE"] ?? "."
            return URL(fileURLWithPath: base)
        #else
            if let xdg = environment["XDG_DATA_HOME"], !xdg.isEmpty {
                return URL(fileURLWithPath: xdg)
            }
            let home = environment["HOME"] ?? "."
            return URL(fileURLWithPath: home).appendingPathComponent(".local/share")
        #endif
    }
}

Step 6: Write Terminal.swift

import Foundation
import KeycaskCore

#if canImport(Darwin)
    import Darwin
#elseif canImport(Glibc)
    import Glibc
#elseif canImport(Musl)
    import Musl
#elseif os(Windows)
    import CRT
    import WinSDK
#endif

enum Terminal {
    static var stdinIsTTY: Bool {
        #if os(Windows)
            return _isatty(_fileno(stdin)) != 0
        #else
            return isatty(STDIN_FILENO) != 0
        #endif
    }

    static func write(_ text: String) {
        FileHandle.standardError.write(Data(text.utf8))
    }

    static func readLine(prompt: String) -> String? {
        write(prompt)
        return Swift.readLine(strippingNewline: true)
    }

    static func confirm(_ question: String) -> Bool {
        guard let answer = readLine(prompt: question + " [y/N] ") else { return false }
        return answer.lowercased().hasPrefix("y")
    }

    static func readSecretLine(prompt: String) throws -> String {
        write(prompt)
        defer { write("\n") }
        return try withEchoDisabled { Swift.readLine(strippingNewline: true) ?? "" }
    }

    #if os(Windows)
        private static func withEchoDisabled<T>(_ body: () throws -> T) throws -> T {
            let handle = GetStdHandle(DWORD(bitPattern: -10))
            var mode: DWORD = 0
            guard GetConsoleMode(handle, &mode).boolValue else {
                throw KeycaskError.io("GetConsoleMode failed")
            }
            SetConsoleMode(handle, mode & ~DWORD(ENABLE_ECHO_INPUT))
            defer { SetConsoleMode(handle, mode) }
            return try body()
        }
    #else
        private static func withEchoDisabled<T>(_ body: () throws -> T) throws -> T {
            var original = termios()
            guard tcgetattr(STDIN_FILENO, &original) == 0 else {
                throw KeycaskError.io("tcgetattr failed")
            }
            var quiet = original
            quiet.c_lflag &= ~tcflag_t(ECHO)
            tcsetattr(STDIN_FILENO, TCSANOW, &quiet)
            defer { tcsetattr(STDIN_FILENO, TCSANOW, &original) }
            return try body()
        }
    #endif
}

Step 7: Write Passphrase.swift

import Foundation
import KeycaskCore

enum Passphrase {
    static let variable = "KEYCASK_PASSPHRASE"

    static func obtain(
        confirm: Bool, environment: [String: String] = ProcessInfo.processInfo.environment
    ) throws -> String {
        if let fromEnv = environment[variable] {
            return try validated(fromEnv)
        }
        guard Terminal.stdinIsTTY else {
            throw KeycaskError.usage("no passphrase: set \(variable) or run on a terminal")
        }
        let first = try Terminal.readSecretLine(prompt: "Passphrase: ")
        if confirm {
            let second = try Terminal.readSecretLine(prompt: "Confirm passphrase: ")
            guard first == second else { throw KeycaskError.failure("passphrases do not match") }
        }
        return try validated(first)
    }

    private static func validated(_ passphrase: String) throws -> String {
        guard !passphrase.isEmpty else { throw KeycaskError.failure("passphrase is empty") }
        return passphrase
    }
}

Step 8: Write AtomicFile.swift

import Foundation
import KeycaskCore

#if canImport(Darwin)
    import Darwin
#elseif canImport(Glibc)
    import Glibc
#elseif canImport(Musl)
    import Musl
#elseif os(Windows)
    import WinSDK
#endif

enum AtomicFile {
    static func write(_ data: Data, to url: URL) throws {
        let directory = url.deletingLastPathComponent()
        let temp = url.appendingPathExtension("tmp")
        do {
            try FileManager.default.createDirectory(at: directory, withIntermediateDirectories: true)
            try writePrivate(data, to: temp)
            try replace(url, with: temp)
        } catch let error as KeycaskError {
            try? FileManager.default.removeItem(at: temp)
            throw error
        } catch {
            try? FileManager.default.removeItem(at: temp)
            throw KeycaskError.io("write \(url.path): \(error)")
        }
    }

    #if os(Windows)
        private static func writePrivate(_ data: Data, to url: URL) throws {
            try data.write(to: url)
            let handle = try FileHandle(forWritingTo: url)
            try handle.synchronize()
            try handle.close()
        }

        private static func replace(_ target: URL, with temp: URL) throws {
            let ok = temp.path.withCString(encodedAs: UTF16.self) { src in
                target.path.withCString(encodedAs: UTF16.self) { dst in
                    MoveFileExW(src, dst, DWORD(MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH))
                }
            }
            guard ok.boolValue else { throw KeycaskError.io("rename \(temp.path): error \(GetLastError())") }
        }
    #else
        private static func writePrivate(_ data: Data, to url: URL) throws {
            let fd = open(url.path, O_WRONLY | O_CREAT | O_TRUNC, 0o600)
            guard fd >= 0 else {
                throw KeycaskError.io("open \(url.path): \(String(cString: strerror(errno)))")
            }
            let handle = FileHandle(fileDescriptor: fd, closeOnDealloc: true)
            try handle.write(contentsOf: data)
            try handle.synchronize()
            try handle.close()
        }

        private static func replace(_ target: URL, with temp: URL) throws {
            guard rename(temp.path, target.path) == 0 else {
                throw KeycaskError.io("rename \(temp.path): \(String(cString: strerror(errno)))")
            }
        }
    #endif
}

Step 9: Write OpenVault.swift

import Foundation
import KeycaskCore

struct OpenVault {
    var vault: Vault
    let kdf: Envelope.KDFParams
    let url: URL
    let passphrase: String

    static func load(_ options: GlobalOptions) throws -> OpenVault {
        let url = Paths.vaultURL(override: options.vault)
        let data: Data
        do {
            data = try Data(contentsOf: url)
        } catch let error as CocoaError where error.code == .fileReadNoSuchFile {
            throw KeycaskError.noVault(url.path)
        } catch {
            if !FileManager.default.fileExists(atPath: url.path) {
                throw KeycaskError.noVault(url.path)
            }
            throw KeycaskError.io("read \(url.path): \(error)")
        }
        let envelope = try Envelope(parsing: data)
        let passphrase = try Passphrase.obtain(confirm: false)
        let plaintext = try envelope.open(passphrase: passphrase)
        let vault = try VaultCodec.decode(plaintext)
        return OpenVault(vault: vault, kdf: envelope.kdf, url: url, passphrase: passphrase)
    }

    static func create(_ options: GlobalOptions) throws -> URL {
        let url = Paths.vaultURL(override: options.vault)
        guard !FileManager.default.fileExists(atPath: url.path) else {
            throw KeycaskError.vaultExists(url.path)
        }
        let passphrase = try Passphrase.obtain(confirm: true)
        let fresh = OpenVault(vault: Vault(), kdf: .fresh(), url: url, passphrase: passphrase)
        try fresh.save()
        return url
    }

    func save() throws {
        let plaintext = try VaultCodec.encode(vault)
        let envelope = try Envelope.seal(plaintext, passphrase: passphrase, kdf: kdf)
        try AtomicFile.write(try envelope.encoded(), to: url)
    }
}

Step 10: Write Keycask.swift and Commands/Init.swift

Sources/keycask/Keycask.swift:

import ArgumentParser

struct GlobalOptions: ParsableArguments {
    @Option(name: .long, help: "Path to the vault file.")
    var vault: String?
}

struct Keycask: ParsableCommand {
    static let configuration = CommandConfiguration(
        commandName: "keycask",
        abstract: "Command-line password manager. One passphrase-encrypted vault file.",
        subcommands: [Init.self]
    )
}

Sources/keycask/Commands/Init.swift:

import ArgumentParser

struct Init: ParsableCommand {
    static let configuration = CommandConfiguration(abstract: "Create an empty vault.")

    @OptionGroup var global: GlobalOptions

    func run() throws {
        let url = try OpenVault.create(global)
        print("created \(url.path)")
    }
}

Step 11: Write main.swift

import ArgumentParser
import Foundation
import KeycaskCore

func fail(_ text: String, code: Int32) -> Never {
    FileHandle.standardError.write(Data((text + "\n").utf8))
    exit(code)
}

do {
    var command = try Keycask.parseAsRoot()
    try command.run()
} catch let error as KeycaskError {
    fail(error.message, code: error.exitCode)
} catch {
    let text = Keycask.fullMessage(for: error)
    if Keycask.exitCode(for: error).isSuccess {
        print(text)
        exit(0)
    }
    fail(text, code: 2)
}

Step 12: Run tests

Run: swift test --filter 'InitTests|PathsTests' Expected: all pass. The init tests take about half a second each because of 600000 PBKDF2 rounds; that is expected.

Step 13: Lint and commit

swift format lint --strict --recursive Sources Tests
git add Sources/keycask Tests/KeycaskCLITests
git commit -m "Add CLI skeleton with init, paths, passphrase, atomic write"

Task 10: `add`, `show`, and output formatting

Files:

Create: Sources/keycask/Output.swift
Create: Sources/keycask/Commands/Add.swift
Create: Sources/keycask/Commands/Show.swift
Modify: Sources/keycask/Keycask.swift (register subcommands)
Create: Tests/KeycaskCLITests/AddShowTests.swift

Interfaces:

Consumes: OpenVault, Generator, Entry, Terminal, VaultCodec.makeEncoder().
Produces:

enum Output {
    static let mask = "********"
    static func masked(_ entry: Entry, reveal: Bool) -> Entry
    static func text(_ entry: Entry, reveal: Bool) -> String       // "field: value" lines
    static func table(_ entries: [Entry]) -> String                // id name username url
    static func json(_ entries: [Entry], reveal: Bool) throws -> String
    static func json(_ entry: Entry, reveal: Bool) throws -> String
    static func field(_ entry: Entry, named: String) throws -> String  // usage error for unknown field
}
enum PasswordInput {
    static func read(prompt: String) throws -> String   // TTY: hidden prompt; else first line of stdin
}
struct PasswordOptions: ParsableArguments { var generate: Bool; var length: Int?; var words: Int?; func validate(); func newPassword() throws -> String? }

Non-TTY password entry: when stdin is not a terminal, add and edit --password read the password as the first line of stdin. Add this sentence to the spec's CLI section in this task.

Step 1: Write the failing tests

Tests/KeycaskCLITests/AddShowTests.swift:

import Foundation
import Testing

@Suite struct AddShowTests {
    @Test func addReadsPasswordFromStdinAndPrintsID() throws {
        let cli = try CLI.initialized()
        let r = try cli.run(["add", "github", "-u", "cmc", "--url", "https://github.com", "--tag", "dev"],
                            stdin: "hunter2\n")
        #expect(r.status == 0)
        let id = r.stdout.trimmingCharacters(in: .whitespacesAndNewlines)
        #expect(id.count == 8)

        let shown = try cli.run(["show", id])
        #expect(shown.status == 0)
        #expect(shown.stdout.contains("name: github"))
        #expect(shown.stdout.contains("username: cmc"))
        #expect(shown.stdout.contains("password: ********"))
        #expect(shown.stdout.contains("tags: dev"))
        #expect(!shown.stdout.contains("hunter2"))
    }

    @Test func showByNameRevealAndField() throws {
        let cli = try CLI.initialized()
        try cli.run(["add", "github"], stdin: "hunter2\n")
        let revealed = try cli.run(["show", "github", "--reveal"])
        #expect(revealed.stdout.contains("password: hunter2"))
        let field = try cli.run(["show", "github", "--field", "password"])
        #expect(field.stdout == "hunter2\n")
        let missing = try cli.run(["show", "github", "--field", "url"])
        #expect(missing.status == 0)
        #expect(missing.stdout == "\n")
        let unknown = try cli.run(["show", "github", "--field", "nope"])
        #expect(unknown.status == 2)
    }

    @Test func jsonMasksUnlessReveal() throws {
        let cli = try CLI.initialized()
        try cli.run(["add", "github", "-u", "cmc"], stdin: "hunter2\n")
        let masked = try cli.run(["show", "github", "--json"])
        let obj = try JSONSerialization.jsonObject(with: Data(masked.stdout.utf8)) as! [String: Any]
        #expect(obj["name"] as? String == "github")
        #expect(obj["username"] as? String == "cmc")
        #expect(obj["password"] as? String == "********")
        #expect((obj["id"] as? String)?.count == 8)
        #expect((obj["created"] as? String)?.hasSuffix("Z") == true)
        let revealed = try cli.run(["show", "github", "--json", "--reveal"])
        let obj2 = try JSONSerialization.jsonObject(with: Data(revealed.stdout.utf8)) as! [String: Any]
        #expect(obj2["password"] as? String == "hunter2")
    }

    @Test func addGenerateAndWords() throws {
        let cli = try CLI.initialized()
        try cli.run(["add", "a", "--generate"])
        try cli.run(["add", "b", "--generate", "--length", "40"])
        try cli.run(["add", "c", "--words", "4"])
        #expect(try cli.run(["show", "a", "--field", "password"]).stdout.count == 25)
        #expect(try cli.run(["show", "b", "--field", "password"]).stdout.count == 41)
        let words = try cli.run(["show", "c", "--field", "password"]).stdout
            .trimmingCharacters(in: .newlines).split(separator: "-")
        #expect(words.count == 4)
    }

    @Test func generateAndWordsTogetherIsUsageError() throws {
        let cli = try CLI.initialized()
        let r = try cli.run(["add", "a", "--generate", "--words", "3"])
        #expect(r.status == 2)
    }

    @Test func duplicateNamesAreAllowedAndAmbiguousOnShow() throws {
        let cli = try CLI.initialized()
        let a = try cli.run(["add", "gh", "-u", "one", "--generate"]).stdout.trimmingCharacters(in: .newlines)
        let b = try cli.run(["add", "gh", "-u", "two", "--generate"]).stdout.trimmingCharacters(in: .newlines)
        let r = try cli.run(["show", "gh"])
        #expect(r.status == 5)
        #expect(r.stderr.contains(a) && r.stderr.contains(b))
        #expect(try cli.run(["show", a]).stdout.contains("username: one"))
    }

    @Test func missingEntryIsNotFound() throws {
        let cli = try CLI.initialized()
        let r = try cli.run(["show", "nope"])
        #expect(r.status == 3)
        #expect(r.stderr == "nope: not found\n")
    }

    @Test func wrongPassphraseCannotDecrypt() throws {
        let cli = try CLI.initialized()
        let r = try cli.run(["show", "x"], passphrase: "wrong")
        #expect(r.status == 4)
        #expect(r.stderr.contains("cannot decrypt"))
    }

    @Test func missingVaultIsNotFound() throws {
        let cli = try CLI()
        let r = try cli.run(["show", "x"])
        #expect(r.status == 3)
        #expect(r.stderr.contains("keycask init"))
    }

    @Test func corruptVaultIsFailure() throws {
        let cli = try CLI.initialized()
        try Data("{}".utf8).write(to: cli.vault)
        let r = try cli.run(["show", "x"])
        #expect(r.status == 1)
        #expect(r.stderr.hasPrefix("vault is corrupt"))
    }
}

Step 2: Run tests to verify they fail

Run: swift test --filter AddShowTests Expected: failures, add is an unknown subcommand (exit 2).

Step 3: Write Output.swift

import Foundation
import KeycaskCore

enum Output {
    static let mask = "********"

    static func masked(_ entry: Entry, reveal: Bool) -> Entry {
        guard !reveal else { return entry }
        var copy = entry
        copy.password = mask
        return copy
    }

    static func text(_ entry: Entry, reveal: Bool) -> String {
        let e = masked(entry, reveal: reveal)
        var lines = ["id: \(e.id.rawValue)", "name: \(e.name)"]
        if let u = e.username { lines.append("username: \(u)") }
        lines.append("password: \(e.password)")
        if let u = e.url { lines.append("url: \(u)") }
        if !e.tags.isEmpty { lines.append("tags: \(e.tags.joined(separator: ", "))") }
        if let n = e.notes { lines.append("notes: \(n)") }
        lines.append("created: \(iso(e.created))")
        lines.append("updated: \(iso(e.updated))")
        return lines.joined(separator: "\n") + "\n"
    }

    static func table(_ entries: [Entry]) -> String {
        guard !entries.isEmpty else { return "" }
        let rows = entries.map { [$0.id.rawValue, $0.name, $0.username ?? "", $0.url ?? ""] }
        let widths = (0..<3).map { col in rows.map { $0[col].count }.max() ?? 0 }
        return rows.map { row in
            let padded = (0..<3).map { row[$0].padding(toLength: widths[$0], withPad: " ", startingAt: 0) }
            return (padded + [row[3]]).joined(separator: "  ")
                .trimmingCharacters(in: .whitespaces)
        }.joined(separator: "\n") + "\n"
    }

    static func json(_ entries: [Entry], reveal: Bool) throws -> String {
        try encode(entries.map { masked($0, reveal: reveal) })
    }

    static func json(_ entry: Entry, reveal: Bool) throws -> String {
        try encode(masked(entry, reveal: reveal))
    }

    static func field(_ entry: Entry, named name: String) throws -> String {
        switch name {
        case "id": entry.id.rawValue
        case "name": entry.name
        case "username": entry.username ?? ""
        case "password": entry.password
        case "url": entry.url ?? ""
        case "notes": entry.notes ?? ""
        case "tags": entry.tags.joined(separator: ",")
        case "created": iso(entry.created)
        case "updated": iso(entry.updated)
        default: throw KeycaskError.usage("unknown field \(name)")
        }
    }

    private static func encode(_ value: some Encodable) throws -> String {
        let encoder = VaultCodec.makeEncoder()
        encoder.outputFormatting.insert(.prettyPrinted)
        do {
            return String(decoding: try encoder.encode(value), as: UTF8.self) + "\n"
        } catch {
            throw KeycaskError.io("encode json: \(error)")
        }
    }

    private static func iso(_ date: Date) -> String {
        date.formatted(.iso8601)
    }
}

Step 4: Write password input and the shared password options

Add to Sources/keycask/Commands/Add.swift:

import ArgumentParser
import Foundation
import KeycaskCore

enum PasswordInput {
    static func read(prompt: String) throws -> String {
        if Terminal.stdinIsTTY {
            return try Terminal.readSecretLine(prompt: prompt)
        }
        guard let line = Swift.readLine(strippingNewline: true) else {
            throw KeycaskError.usage("no password: pass one on stdin or run on a terminal")
        }
        return line
    }
}

struct PasswordOptions: ParsableArguments {
    @Flag(name: .long, help: "Generate a random password.")
    var generate = false

    @Option(name: .long, help: "Length of the generated password (default 24).")
    var length: Int?

    @Option(name: .long, help: "Generate a passphrase of this many words instead.")
    var words: Int?

    mutating func validate() throws {
        if generate, words != nil {
            throw ValidationError("--generate and --words are mutually exclusive")
        }
        if let length, length < 1 { throw ValidationError("--length must be at least 1") }
        if let words, words < 1 { throw ValidationError("--words must be at least 1") }
        if length != nil, !generate, words == nil {
            throw ValidationError("--length requires --generate")
        }
    }

    /// nil means the caller must prompt.
    func newPassword() -> String? {
        if let words { return Generator.passphrase(words: words) }
        if generate { return Generator.password(length: length ?? Generator.defaultLength) }
        return nil
    }
}

struct Add: ParsableCommand {
    static let configuration = CommandConfiguration(abstract: "Add an entry.")

    @OptionGroup var global: GlobalOptions
    @Argument(help: "Entry name. Names may repeat; the printed id is unique.") var name: String
    @Option(name: [.short, .customLong("username")], help: "Username.") var username: String?
    @Option(name: .long, help: "URL.") var url: String?
    @Option(name: .long, help: "Notes.") var notes: String?
    @Option(name: .long, help: "Tag. Repeatable.") var tag: [String] = []
    @OptionGroup var password: PasswordOptions

    func run() throws {
        var open = try OpenVault.load(global)
        let secret = try password.newPassword() ?? PasswordInput.read(prompt: "Password: ")
        var entry = Entry(name: name, username: username, password: secret, url: url,
                          notes: notes, tags: tag)
        while open.vault.entry(id: entry.id) != nil {
            entry = Entry(name: name, username: username, password: secret, url: url,
                          notes: notes, tags: tag)
        }
        try open.vault.add(entry)
        try open.save()
        print(entry.id.rawValue)
    }
}

Step 5: Write Commands/Show.swift

import ArgumentParser
import KeycaskCore

struct Show: ParsableCommand {
    static let configuration = CommandConfiguration(abstract: "Show an entry.")

    @OptionGroup var global: GlobalOptions
    @Argument(help: "Entry id or name.") var ref: String
    @Flag(name: .long, help: "Show the password.") var reveal = false
    @Option(name: .long, help: "Print one field, unmasked.") var field: String?
    @Flag(name: .long, help: "JSON output.") var json = false

    func run() throws {
        let open = try OpenVault.load(global)
        let entry = try open.vault.resolve(ref)
        if let field {
            print(try Output.field(entry, named: field))
        } else if json {
            print(try Output.json(entry, reveal: reveal), terminator: "")
        } else {
            print(Output.text(entry, reveal: reveal), terminator: "")
        }
    }
}

Step 6: Register the subcommands

In Keycask.swift: subcommands: [Init.self, Add.self, Show.self].

Step 7: Amend the spec

In docs/superpowers/specs/2026-09-17-keycask-design.md, after the sentence beginning "Passphrase input:", add a paragraph:

Password input for `add` and `edit --password`: on a terminal, a hidden
prompt. Without a terminal, the first line of stdin. Neither available is
exit 2.

Step 8: Run tests

Run: swift test --filter AddShowTests Expected: 10 tests pass.

Step 9: Lint and commit

swift format lint --strict --recursive Sources Tests
git add Sources/keycask Tests/KeycaskCLITests docs
git commit -m "Add add and show commands with masked output"

Task 11: `ls` and `find`

Files:

Create: Sources/keycask/Commands/Ls.swift
Create: Sources/keycask/Commands/Find.swift
Modify: Sources/keycask/Keycask.swift
Create: Tests/KeycaskCLITests/LsFindTests.swift

Interfaces:

Consumes: OpenVault, Output.table, Output.json(_:[Entry]), Vault.filter(tag:), Vault.search, Vault.sortedEntries.
Step 1: Write the failing tests

import Foundation
import Testing

@Suite struct LsFindTests {
    func seeded() throws -> CLI {
        let cli = try CLI.initialized()
        try cli.run(["add", "github", "-u", "cmc", "--url", "https://github.com", "--tag", "Dev", "--generate"])
        try cli.run(["add", "bank", "--url", "https://bank.example", "--notes", "downtown branch", "--generate"])
        try cli.run(["add", "Alpha", "--tag", "dev", "--generate"])
        return cli
    }

    @Test func lsSortsByNameAndShowsColumns() throws {
        let cli = try seeded()
        let r = try cli.run(["ls"])
        #expect(r.status == 0)
        let names = r.lines.map { String($0.split(separator: " ", omittingEmptySubsequences: true)[1]) }
        #expect(names == ["Alpha", "bank", "github"])
        #expect(r.stdout.contains("cmc"))
        #expect(r.stdout.contains("https://github.com"))
    }

    @Test func lsTagFilterIsCaseInsensitive() throws {
        let cli = try seeded()
        let r = try cli.run(["ls", "--tag", "DEV"])
        #expect(r.lines.count == 2)
        #expect(!r.stdout.contains("bank"))
    }

    @Test func lsJsonIsAnArrayWithMaskedPasswords() throws {
        let cli = try seeded()
        let r = try cli.run(["ls", "--json"])
        let arr = try JSONSerialization.jsonObject(with: Data(r.stdout.utf8)) as! [[String: Any]]
        #expect(arr.count == 3)
        #expect(arr.allSatisfy { $0["password"] as? String == "********" })
    }

    @Test func emptyVaultListsNothing() throws {
        let cli = try CLI.initialized()
        let r = try cli.run(["ls"])
        #expect(r.status == 0)
        #expect(r.stdout == "")
        let j = try cli.run(["ls", "--json"])
        #expect(j.stdout.trimmingCharacters(in: .whitespacesAndNewlines) == "[]")
    }

    @Test func findMatchesNotesURLTagsCaseInsensitively() throws {
        let cli = try seeded()
        #expect(try cli.run(["find", "DOWNTOWN"]).lines.count == 1)
        #expect(try cli.run(["find", "github.com"]).lines.count == 1)
        #expect(try cli.run(["find", "dev"]).lines.count == 2)
        let none = try cli.run(["find", "zzz"])
        #expect(none.status == 0)
        #expect(none.stdout == "")
    }

    @Test func findJson() throws {
        let cli = try seeded()
        let r = try cli.run(["find", "bank", "--json"])
        let arr = try JSONSerialization.jsonObject(with: Data(r.stdout.utf8)) as! [[String: Any]]
        #expect(arr.count == 1)
        #expect(arr[0]["name"] as? String == "bank")
    }
}

Step 2: Run tests to verify they fail

Run: swift test --filter LsFindTests Expected: failures, unknown subcommand.

Step 3: Write Ls.swift and Find.swift

Commands/Ls.swift:

import ArgumentParser
import KeycaskCore

struct Ls: ParsableCommand {
    static let configuration = CommandConfiguration(abstract: "List entries.")

    @OptionGroup var global: GlobalOptions
    @Option(name: .long, help: "Only entries with this tag.") var tag: String?
    @Flag(name: .long, help: "JSON output.") var json = false

    func run() throws {
        let open = try OpenVault.load(global)
        let entries = tag.map { open.vault.filter(tag: $0) } ?? open.vault.sortedEntries
        if json {
            print(try Output.json(entries, reveal: false), terminator: "")
        } else {
            print(Output.table(entries), terminator: "")
        }
    }
}

Commands/Find.swift:

import ArgumentParser
import KeycaskCore

struct Find: ParsableCommand {
    static let configuration = CommandConfiguration(abstract: "Search entries.")

    @OptionGroup var global: GlobalOptions
    @Argument(help: "Case-insensitive substring.") var query: String
    @Flag(name: .long, help: "JSON output.") var json = false

    func run() throws {
        let open = try OpenVault.load(global)
        let entries = open.vault.search(query)
        if json {
            print(try Output.json(entries, reveal: false), terminator: "")
        } else {
            print(Output.table(entries), terminator: "")
        }
    }
}

Step 4: Run tests

Run: swift test --filter LsFindTests Expected: 6 tests pass.

Step 5: Lint and commit

swift format lint --strict --recursive Sources Tests
git add Sources/keycask Tests/KeycaskCLITests
git commit -m "Add ls and find commands"

Task 12: `edit` and `rm`

Files:

Create: Sources/keycask/Commands/Edit.swift
Create: Sources/keycask/Commands/Rm.swift
Modify: Sources/keycask/Keycask.swift
Create: Tests/KeycaskCLITests/EditRmTests.swift

Interfaces:

Consumes: OpenVault, Vault.update, Vault.remove, PasswordOptions, PasswordInput, Terminal.confirm, Terminal.stdinIsTTY.
Step 1: Write the failing tests

import Foundation
import Testing

@Suite struct EditRmTests {
    @Test func editChangesFieldsAndBumpsUpdated() throws {
        let cli = try CLI.initialized()
        try cli.run(["add", "gh", "--tag", "a", "--generate"])
        let before = try JSONSerialization.jsonObject(
            with: Data(try cli.run(["show", "gh", "--json"]).stdout.utf8)) as! [String: Any]
        let r = try cli.run([
            "edit", "gh", "--name", "github", "-u", "cmc", "--url", "https://x", "--notes", "n",
            "--tag", "b", "--untag", "a",
        ])
        #expect(r.status == 0)
        let after = try JSONSerialization.jsonObject(
            with: Data(try cli.run(["show", "github", "--json"]).stdout.utf8)) as! [String: Any]
        #expect(after["name"] as? String == "github")
        #expect(after["username"] as? String == "cmc")
        #expect(after["url"] as? String == "https://x")
        #expect(after["notes"] as? String == "n")
        #expect(after["tags"] as? [String] == ["b"])
        #expect(after["created"] as? String == before["created"] as? String)
        #expect(after["id"] as? String == before["id"] as? String)
    }

    @Test func editPasswordFromStdinAndGenerate() throws {
        let cli = try CLI.initialized()
        try cli.run(["add", "gh", "--generate"])
        try cli.run(["edit", "gh", "--password"], stdin: "newpass\n")
        #expect(try cli.run(["show", "gh", "--field", "password"]).stdout == "newpass\n")
        try cli.run(["edit", "gh", "--generate", "--length", "30"])
        #expect(try cli.run(["show", "gh", "--field", "password"]).stdout.count == 31)
    }

    @Test func editWithNoChangesIsUsageError() throws {
        let cli = try CLI.initialized()
        try cli.run(["add", "gh", "--generate"])
        let r = try cli.run(["edit", "gh"])
        #expect(r.status == 2)
    }

    @Test func editUnknownIsNotFound() throws {
        let cli = try CLI.initialized()
        #expect(try cli.run(["edit", "nope", "--url", "x"]).status == 3)
    }

    @Test func rmWithYesRemoves() throws {
        let cli = try CLI.initialized()
        let id = try cli.run(["add", "gh", "--generate"]).stdout.trimmingCharacters(in: .newlines)
        let r = try cli.run(["rm", id, "--yes"])
        #expect(r.status == 0)
        #expect(try cli.run(["show", id]).status == 3)
        #expect(try cli.run(["ls"]).stdout == "")
    }

    @Test func rmWithoutYesAndWithoutTTYIsUsageError() throws {
        let cli = try CLI.initialized()
        try cli.run(["add", "gh", "--generate"])
        let r = try cli.run(["rm", "gh"], stdin: "y\n")
        #expect(r.status == 2)
        #expect(r.stderr.contains("--yes"))
        #expect(try cli.run(["ls"]).lines.count == 1)
    }

    @Test func rmAmbiguousNameLists() throws {
        let cli = try CLI.initialized()
        try cli.run(["add", "gh", "--generate"])
        try cli.run(["add", "gh", "--generate"])
        let r = try cli.run(["rm", "gh", "--yes"])
        #expect(r.status == 5)
        #expect(try cli.run(["ls"]).lines.count == 2)
    }
}

Step 2: Run tests to verify they fail

Run: swift test --filter EditRmTests Expected: failures, unknown subcommand.

Step 3: Write Edit.swift

import ArgumentParser
import KeycaskCore

struct Edit: ParsableCommand {
    static let configuration = CommandConfiguration(abstract: "Change an entry.")

    @OptionGroup var global: GlobalOptions
    @Argument(help: "Entry id or name.") var ref: String
    @Option(name: .long, help: "New name.") var name: String?
    @Option(name: [.short, .customLong("username")], help: "New username.") var username: String?
    @Option(name: .long, help: "New URL.") var url: String?
    @Option(name: .long, help: "New notes.") var notes: String?
    @Option(name: .long, help: "Add a tag. Repeatable.") var tag: [String] = []
    @Option(name: .long, help: "Remove a tag. Repeatable.") var untag: [String] = []
    @Flag(name: .long, help: "Prompt for a new password.") var password = false
    @OptionGroup var generated: PasswordOptions

    mutating func validate() throws {
        let changes = [name, username, url, notes].contains { $0 != nil }
            || !tag.isEmpty || !untag.isEmpty || password || generated.generate || generated.words != nil
        guard changes else { throw ValidationError("nothing to change") }
        if password, generated.newPassword() != nil {
            throw ValidationError("--password cannot be combined with --generate or --words")
        }
    }

    func run() throws {
        var open = try OpenVault.load(global)
        let target = try open.vault.resolve(ref)
        let newSecret: String? =
            password ? try PasswordInput.read(prompt: "New password: ") : generated.newPassword()
        try open.vault.update(id: target.id) { e in
            if let name { e.name = name }
            if let username { e.username = username }
            if let url { e.url = url }
            if let notes { e.notes = notes }
            if let newSecret { e.password = newSecret }
            let drop = Set(untag.map { $0.lowercased() })
            e.tags = e.tags.filter { !drop.contains($0.lowercased()) } + tag
        }
        try open.save()
    }
}

Step 4: Write Rm.swift

import ArgumentParser
import KeycaskCore

struct Rm: ParsableCommand {
    static let configuration = CommandConfiguration(abstract: "Remove an entry.")

    @OptionGroup var global: GlobalOptions
    @Argument(help: "Entry id or name.") var ref: String
    @Flag(name: .long, help: "Do not ask for confirmation.") var yes = false

    func run() throws {
        var open = try OpenVault.load(global)
        let target = try open.vault.resolve(ref)
        if !yes {
            guard Terminal.stdinIsTTY else {
                throw KeycaskError.usage("refusing to remove without --yes when not on a terminal")
            }
            guard Terminal.confirm("remove \(target.name) (\(target.id.rawValue))?") else {
                throw KeycaskError.failure("aborted")
            }
        }
        try open.vault.remove(id: target.id)
        try open.save()
    }
}

Step 5: Run tests

Run: swift test --filter EditRmTests Expected: 7 tests pass.

Step 6: Lint and commit

swift format lint --strict --recursive Sources Tests
git add Sources/keycask Tests/KeycaskCLITests
git commit -m "Add edit and rm commands"

Task 13: `generate`

Files:

Create: Sources/keycask/Commands/Generate.swift
Modify: Sources/keycask/Keycask.swift
Create: Tests/KeycaskCLITests/GenerateTests.swift

Interfaces:

Consumes: Generator. --copy calls Clipboard.copyWithTimeout, which does not exist until Task 14; in this task --copy is declared but run() throws KeycaskError.failure("clipboard not available") when it is set. Task 14 replaces that line.
Step 1: Write the failing tests

import Foundation
import Testing

@Suite struct GenerateTests {
    @Test func defaultIs24Characters() throws {
        let cli = try CLI()
        let r = try cli.run(["generate"], passphrase: nil)
        #expect(r.status == 0)
        #expect(r.stdout.count == 25)
    }

    @Test func lengthAndWords() throws {
        let cli = try CLI()
        #expect(try cli.run(["generate", "--length", "12"], passphrase: nil).stdout.count == 13)
        let w = try cli.run(["generate", "--words", "6"], passphrase: nil).stdout
            .trimmingCharacters(in: .newlines).split(separator: "-")
        #expect(w.count == 6)
    }

    @Test func doesNotNeedAVault() throws {
        let cli = try CLI()
        #expect(!FileManager.default.fileExists(atPath: cli.vault.path))
        #expect(try cli.run(["generate"], passphrase: nil).status == 0)
    }

    @Test func lengthAndWordsTogetherIsUsageError() throws {
        let cli = try CLI()
        #expect(try cli.run(["generate", "--length", "3", "--words", "3"], passphrase: nil).status == 2)
    }
}

Step 2: Run tests to verify they fail

Run: swift test --filter GenerateTests Expected: failures, unknown subcommand.

Step 3: Write Generate.swift

import ArgumentParser
import KeycaskCore

struct Generate: ParsableCommand {
    static let configuration = CommandConfiguration(abstract: "Generate a password.")

    @Option(name: .long, help: "Password length (default 24).") var length: Int?
    @Option(name: .long, help: "Passphrase of this many words instead.") var words: Int?
    @Flag(name: .long, help: "Copy to the clipboard instead of printing.") var copy = false

    mutating func validate() throws {
        if length != nil, words != nil {
            throw ValidationError("--length and --words are mutually exclusive")
        }
        if let length, length < 1 { throw ValidationError("--length must be at least 1") }
        if let words, words < 1 { throw ValidationError("--words must be at least 1") }
    }

    func run() throws {
        let secret =
            words.map { Generator.passphrase(words: $0) }
            ?? Generator.password(length: length ?? Generator.defaultLength)
        if copy {
            throw KeycaskError.failure("clipboard not available")
        }
        print(secret)
    }
}

Step 4: Run tests

Run: swift test --filter GenerateTests Expected: 4 tests pass.

Step 5: Lint and commit

swift format lint --strict --recursive Sources Tests
git add Sources/keycask Tests/KeycaskCLITests
git commit -m "Add generate command"

Task 14: Clipboard, `clip`, daemon, `generate --copy`

Files:

Create: Sources/keycask/Clipboard.swift
Create: Sources/keycask/Commands/Clip.swift
Create: Sources/keycask/Commands/ClipboardDaemon.swift
Modify: Sources/keycask/Commands/Generate.swift
Modify: Sources/keycask/Keycask.swift
Create: Tests/KeycaskCLITests/ClipboardTests.swift

Interfaces:

Produces:

enum Clipboard {
    struct Handoff: Codable, Equatable { var secret: String; var previous: String }
    struct Tool { let copy: [String]; let paste: [String] }
    static let timeoutSeconds = 45
    static func shouldRestore(secret: String, current: String?) -> Bool
    static func findTool(path: String, fileManager: FileManager = .default) -> Tool?
    static func read() throws -> String
    static func write(_ text: String) throws
    static func copyWithTimeout(_ secret: String, seconds: Int = timeoutSeconds) throws
    static func runDaemon(seconds: Int) throws
}

The tests never touch the real clipboard. They cover the restore decision, tool discovery against a fake PATH, and the daemon's handoff parsing.

Step 1: Write the failing tests

Tests/KeycaskCLITests/ClipboardTests.swift:

import Foundation
import Testing

@testable import keycask

@Suite struct ClipboardTests {
    @Test func restoresOnlyWhenClipboardStillHoldsTheSecret() {
        #expect(Clipboard.shouldRestore(secret: "s", current: "s"))
        #expect(!Clipboard.shouldRestore(secret: "s", current: "user pasted"))
        #expect(!Clipboard.shouldRestore(secret: "s", current: nil))
    }

    @Test func handoffRoundTrips() throws {
        let h = Clipboard.Handoff(secret: "s3cret", previous: "old")
        let data = try JSONEncoder().encode(h)
        #expect(try JSONDecoder().decode(Clipboard.Handoff.self, from: data) == h)
    }

    @Test func findToolScansPathInOrder() throws {
        let dir = FileManager.default.temporaryDirectory
            .appendingPathComponent("keycask-clip-\(UUID().uuidString)")
        try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
        #expect(Clipboard.findTool(path: dir.path) == nil)

        #if os(macOS)
            let names = ["pbcopy", "pbpaste"]
        #elseif os(Windows)
            let names = ["clip.exe", "powershell.exe"]
        #else
            let names = ["xclip"]
        #endif
        for n in names {
            let f = dir.appendingPathComponent(n)
            try Data("#!/bin/sh\n".utf8).write(to: f)
            try FileManager.default.setAttributes([.posixPermissions: 0o755], ofItemAtPath: f.path)
        }
        let tool = Clipboard.findTool(path: dir.path)
        #expect(tool != nil)
        #expect(tool?.copy.first?.hasPrefix(dir.path) == true)
    }

    @Test func daemonWithoutHandoffFails() throws {
        let cli = try CLI()
        let r = try cli.run(["clipboard-daemon", "1"], stdin: "not json", passphrase: nil)
        #expect(r.status == 1)
    }

    @Test func daemonIsHiddenFromHelp() throws {
        let cli = try CLI()
        let r = try cli.run(["--help"], passphrase: nil)
        #expect(!r.stdout.contains("clipboard-daemon"))
        #expect(r.stdout.contains("clip"))
    }

    @Test func clipOfMissingEntryIsNotFoundBeforeTouchingClipboard() throws {
        let cli = try CLI.initialized()
        let r = try cli.run(["clip", "nope"])
        #expect(r.status == 3)
    }
}

Step 2: Run tests to verify they fail

Run: swift test --filter ClipboardTests Expected: compile error, Clipboard not found.

Step 3: Write Clipboard.swift

import Foundation
import KeycaskCore

enum Clipboard {
    struct Handoff: Codable, Equatable {
        var secret: String
        var previous: String
    }

    struct Tool: Equatable {
        let copy: [String]
        let paste: [String]
    }

    static let timeoutSeconds = 45

    static func shouldRestore(secret: String, current: String?) -> Bool {
        current == secret
    }

    static func findTool(
        path: String = ProcessInfo.processInfo.environment["PATH"] ?? "",
        fileManager: FileManager = .default
    ) -> Tool? {
        #if os(Windows)
            let separator: Character = ";"
            let candidates: [(copy: [String], paste: [String])] = [
                (["clip.exe"], ["powershell.exe", "-NoProfile", "-Command", "Get-Clipboard -Raw"])
            ]
        #elseif os(macOS)
            let separator: Character = ":"
            let candidates: [(copy: [String], paste: [String])] = [(["pbcopy"], ["pbpaste"])]
        #else
            let separator: Character = ":"
            let candidates: [(copy: [String], paste: [String])] = [
                (["wl-copy"], ["wl-paste", "--no-newline"]),
                (["xclip", "-selection", "clipboard"], ["xclip", "-selection", "clipboard", "-o"]),
            ]
        #endif
        let dirs = path.split(separator: separator).map(String.init)
        func locate(_ name: String) -> String? {
            for dir in dirs {
                let full = URL(fileURLWithPath: dir).appendingPathComponent(name).path
                if fileManager.isExecutableFile(atPath: full) { return full }
            }
            return nil
        }
        for candidate in candidates {
            guard let copy = locate(candidate.copy[0]), let paste = locate(candidate.paste[0]) else {
                continue
            }
            return Tool(
                copy: [copy] + candidate.copy.dropFirst(),
                paste: [paste] + candidate.paste.dropFirst())
        }
        return nil
    }

    static func read() throws -> String {
        let tool = try requireTool()
        let (status, output) = try runTool(tool.paste, input: nil)
        guard status == 0 else { return "" }
        return output
    }

    static func write(_ text: String) throws {
        let tool = try requireTool()
        let (status, _) = try runTool(tool.copy, input: text)
        guard status == 0 else { throw KeycaskError.failure("clipboard tool failed") }
    }

    static func copyWithTimeout(_ secret: String, seconds: Int = timeoutSeconds) throws {
        _ = try requireTool()
        let handoff = Handoff(secret: secret, previous: try read())
        let process = Process()
        process.executableURL = Bundle.main.executableURL
        process.arguments = ["clipboard-daemon", String(seconds)]
        process.standardOutput = FileHandle.nullDevice
        process.standardError = FileHandle.nullDevice
        let input = Pipe()
        process.standardInput = input
        do {
            try process.run()
            input.fileHandleForWriting.write(try JSONEncoder().encode(handoff))
            try input.fileHandleForWriting.close()
        } catch {
            throw KeycaskError.failure("start clipboard daemon: \(error)")
        }
    }

    static func runDaemon(seconds: Int) throws {
        let data = FileHandle.standardInput.readDataToEndOfFile()
        let handoff: Handoff
        do {
            handoff = try JSONDecoder().decode(Handoff.self, from: data)
        } catch {
            throw KeycaskError.failure("bad handoff")
        }
        try write(handoff.secret)
        Thread.sleep(forTimeInterval: TimeInterval(seconds))
        let current = try? read()
        guard shouldRestore(secret: handoff.secret, current: current) else { return }
        try write(handoff.previous)
    }

    private static func requireTool() throws -> Tool {
        guard let tool = findTool() else {
            #if os(Windows)
                let hint = "clip.exe and powershell.exe"
            #elseif os(macOS)
                let hint = "pbcopy and pbpaste"
            #else
                let hint = "wl-clipboard or xclip"
            #endif
            throw KeycaskError.failure("no clipboard tool found: install \(hint)")
        }
        return tool
    }

    private static func runTool(_ argv: [String], input: String?) throws -> (Int32, String) {
        let process = Process()
        process.executableURL = URL(fileURLWithPath: argv[0])
        process.arguments = Array(argv.dropFirst())
        let out = Pipe()
        process.standardOutput = out
        process.standardError = FileHandle.nullDevice
        let inPipe = Pipe()
        process.standardInput = inPipe
        do {
            try process.run()
        } catch {
            throw KeycaskError.failure("run \(argv[0]): \(error)")
        }
        if let input { inPipe.fileHandleForWriting.write(Data(input.utf8)) }
        try? inPipe.fileHandleForWriting.close()
        let data = out.fileHandleForReading.readDataToEndOfFile()
        process.waitUntilExit()
        return (process.terminationStatus, String(decoding: data, as: UTF8.self))
    }
}

Step 4: Write Clip.swift and ClipboardDaemon.swift

Commands/Clip.swift:

import ArgumentParser
import KeycaskCore

struct Clip: ParsableCommand {
    static let configuration = CommandConfiguration(
        abstract: "Copy a field to the clipboard. Clears after \(Clipboard.timeoutSeconds) seconds.")

    @OptionGroup var global: GlobalOptions
    @Argument(help: "Entry id or name.") var ref: String
    @Option(name: .long, help: "Field to copy (default password).") var field = "password"

    func run() throws {
        let open = try OpenVault.load(global)
        let entry = try open.vault.resolve(ref)
        let value = try Output.field(entry, named: field)
        try Clipboard.copyWithTimeout(value)
        print("copied \(field) of \(entry.name); clears in \(Clipboard.timeoutSeconds)s")
    }
}

Commands/ClipboardDaemon.swift:

import ArgumentParser

struct ClipboardDaemon: ParsableCommand {
    static let configuration = CommandConfiguration(
        commandName: "clipboard-daemon", shouldDisplay: false)

    @Argument var seconds: Int

    func run() throws {
        try Clipboard.runDaemon(seconds: seconds)
    }
}

In Generate.swift replace the throw KeycaskError.failure("clipboard not available") line with:

try Clipboard.copyWithTimeout(secret)
print("copied; clears in \(Clipboard.timeoutSeconds)s")
return

Register: subcommands: [Init.self, Add.self, Show.self, Ls.self, Find.self, Edit.self, Rm.self, Generate.self, Clip.self, ClipboardDaemon.self].

Step 5: Run tests

Run: swift test --filter ClipboardTests Expected: 6 tests pass.

Step 6: Manual check on macOS

swift build && KEYCASK_VAULT=/tmp/kc-manual.kc KEYCASK_PASSPHRASE=pw .build/debug/keycask init
KEYCASK_VAULT=/tmp/kc-manual.kc KEYCASK_PASSPHRASE=pw .build/debug/keycask add t --generate
KEYCASK_VAULT=/tmp/kc-manual.kc KEYCASK_PASSPHRASE=pw .build/debug/keycask clip t && pbpaste | wc -c
sleep 46 && pbpaste | wc -c
rm /tmp/kc-manual.kc

Expected: first wc -c prints 24, second prints the length of whatever was on the clipboard before (0 if it was empty). Record the actual output in the commit message body if it differs.

Step 7: Lint and commit

swift format lint --strict --recursive Sources Tests
git add Sources/keycask Tests/KeycaskCLITests
git commit -m "Add clipboard support: clip, generate --copy, timed clear"

Task 15: README, full verification, CLI merge request

Files:

Modify: README.md
Step 1: Write the README

# keycask

Command-line password manager. One passphrase-encrypted vault file.
Swift, runs on macOS, Linux, and Windows.

## install

```sh
swift build -c release
cp .build/release/keycask ~/.local/bin/
```

## use

```sh
keycask init
keycask add github -u cmc --url https://github.com --tag dev --generate
keycask add mail --words 6
keycask add bank                     # prompts for the password
keycask show github                  # password masked
keycask show github --reveal
keycask show github --field password # raw value, for scripts
keycask clip github                  # clipboard, clears after 45s
keycask ls --tag dev
keycask find example
keycask edit github --tag work --untag dev
keycask rm github --yes
keycask generate --words 5 --copy
```

Every read command takes `--json`. Passwords are masked unless `--reveal`.

Names are labels and may repeat. Every command that takes a name also
takes the entry's 8-character id, which `ls` and `add` print. An
ambiguous name lists the candidates.

## files

| what | default | override |
|---|---|---|
| vault | `~/.local/share/keycask/vault.kc` (`%LOCALAPPDATA%\keycask\vault.kc` on Windows) | `KEYCASK_VAULT`, `--vault` |
| passphrase | prompted | `KEYCASK_PASSPHRASE` |

The vault is a JSON envelope: PBKDF2-HMAC-SHA256 (600000 rounds) over
the passphrase, ChaCha20-Poly1305 over the entries. Writes are atomic.

## exit codes

0 ok, 1 failure, 2 usage, 3 not found, 4 cannot decrypt, 5 ambiguous name.

## develop

```sh
swift build
swift test
swift format lint --strict --recursive Sources Tests
```

Design: `docs/superpowers/specs/2026-09-17-keycask-design.md`.

Step 2: Full suite, lint, release build

Run: swift test && swift format lint --strict --recursive Sources Tests Package.swift && swift build -c release Expected: all tests pass, no lint output, release binary at .build/release/keycask.

Step 3: Commit, push, open MR

git add README.md
git commit -m "Write README for the CLI"
git push -u origin cli
gitbay mr create --source cli --target main --title "CLI: init, add, show, ls, find, edit, rm, generate, clip" --file - <<'EOF'
ArgumentParser commands over KeycaskCore. Paths, hidden passphrase prompt,
atomic writes, shell-out clipboard with timed clear. Black-box CLI tests
cover every command and exit code.
EOF

Step 4: Wait for CI, merge, clean up

Run gitbay build list --json until green. Then:

gitbay mr merge <n> --strategy squash
git switch main && git pull && git branch -D cli && git push origin --delete cli

Do not merge red. If Linux CI fails on something platform-specific (a Glibc import, posixPermissions), fix it on the branch and push again.

docs/superpowers/plans/2026-09-17-core-cli.md

keycask core + CLI Implementation Plan

Global Constraints

File structure

Task 1: Package scaffold and CI

Task 2: KeycaskError

Task 3: EntryID

Task 4: Entry

Task 5: Vault and VaultCodec

Task 6: Generator and word list

Task 7: Envelope

Task 8: Core merge request

Task 9: CLI skeleton, paths, passphrase, atomic write, init

Task 10: add, show, and output formatting

Task 11: ls and find

Task 12: edit and rm

Task 13: generate

Task 14: Clipboard, clip, daemon, generate --copy

Task 15: README, full verification, CLI merge request

Task 9: CLI skeleton, paths, passphrase, atomic write, `init`

Task 10: `add`, `show`, and output formatting

Task 11: `ls` and `find`

Task 12: `edit` and `rm`

Task 13: `generate`

Task 14: Clipboard, `clip`, daemon, `generate --copy`