# AGENTS.md — Build guide for Hazel ## Project scope Watch a user-selected download folder, preview file-matching rules, and move or rename approved files with a reversible operation log. Catalogue verdict: yes. The core loop is small enough for a capable coding agent to produce a useful local version in one sitting. For Hazel, watch selected folders and apply transparent file rules with previews and logs. The hard boundary is mature filesystem automation, rule depth, apple integrations, and reliability, plus os integration polish and maintenance. Use the implementation prompt below to define the deliverable. Complete each phase's acceptance checks before extending the scope. ## Working agreement - Inspect the repository and its existing instructions before choosing paths, dependencies or commands. Keep one coherent stack and explain changes to the proposed architecture. - Plan a vertical slice that accepts a real input and produces the useful output described below. Persist only the state the prompt calls for; respect memory-only and upstream-managed workflows. Use fixtures only when they are clearly labelled. - After scaffolding, document the actual install, development, check and build commands in README and keep them synchronized with the package or project manifest. Do not report commands as successful unless they ran. - Work in small steps. At handoff, list implemented flows, checks actually performed, remaining blockers, and any credentials or provider setup the owner must supply. - Do not publish, spend money, contact customers, delete source data or run irreversible migrations without the project owner's authorization. ## Prerequisites - Runtime and tools: Swift, SwiftUI/AppKit and SQLite on macOS, with secrets in Keychain where needed. - Before starting: A Mac, the current Xcode toolchain and a documented permission checklist; distribution signing is a separate delivery task. ## Stack and architecture - Swift, SwiftUI/AppKit and SQLite on macOS, with secrets in Keychain where needed - Data design: Store WatchedFolder, RuleVersion, FileFingerprint, PlannedAction and Receipt; exclude destination folders from reprocessing and detect name collisions before touching the source. - Setup: A Mac, the current Xcode toolchain and a documented permission checklist; distribution signing is a separate delivery task ## Security and data integrity - Ask for each operating-system permission when its feature is used. Handle denial and revocation without a loop; show permission status and keep local history deletable. - Default to dry-run and keep an undo map. Rules cannot execute arbitrary shell scripts initially; disappearing volumes and revoked folder permissions pause processing rather than deleting records. - Keep secrets outside client bundles and exported projects; document what leaves the device and make retention/deletion controls visible. ## Agent implementation rules - Project rule — domain: Store WatchedFolder, RuleVersion, FileFingerprint, PlannedAction and Receipt; exclude destination folders from reprocessing and detect name collisions before touching the source. - Project rule — scope and recovery: Default to dry-run and keep an undo map. Rules cannot execute arbitrary shell scripts initially; disappearing volumes and revoked folder permissions pause processing rather than deleting records. - Project rule — acceptance: Drop a partially downloaded file, then finish it and create a same-name destination; wait for stability, preview the collision and never overwrite either file silently. - Project rule — delivery: document real setup commands and permissions; do not claim a build, accuracy level, performance result or security certification that has not been demonstrated. ## Optional agent skills and references - Recommended skill: [swiftui-expert-skill](https://github.com/AvdLee/SwiftUI-Agent-Skill/blob/main/skills/swiftui-expert-skill/SKILL.md) — design native SwiftUI state, accessible controls and permission/error views for the proposed Apple-platform interface. Follow the maintainer's installation instructions and match its requirements to the chosen runtime. - Recommended skill: [swift-concurrency](https://github.com/AvdLee/Swift-Concurrency-Agent-Skill/blob/main/skills/swift-concurrency/SKILL.md) — isolate capture, background work and UI updates, and make cancellation invalidate late callbacks. Follow the maintainer's installation instructions and match its requirements to the chosen runtime. Read the linked SKILL.md and its dependencies before adding a skill. Select only the skills matching this project's runtime and task; their documentation does not supply API access, credentials or approval to perform external actions. Pin the reviewed revision where the tool supports it. Follow the chosen agent's documented project-level installation mechanism. ## Distribution ideas These are optional planning notes. Obtain the owner's approval before publishing or contacting anyone. - Demonstrate this working slice using synthetic or explicitly authorized non-sensitive examples: Watch a user-selected download folder, preview file-matching rules, and move or rename approved files with a reversible operation log. - Share a synthetic example export and the acceptance walkthrough; keep real customer, health, financial and source data private: Drop a partially downloaded file, then finish it and create a same-name destination; wait for stability, preview the collision and never overwrite either file silently. - State the limits before asking someone to replace their existing tool: Default to dry-run and keep an undo map. Rules cannot execute arbitrary shell scripts initially; disappearing volumes and revoked folder permissions pause processing rather than deleting records. ## Engineering roadmap 1. Phase 1 — Pin the working slice and create its example input: Watch a user-selected download folder, preview file-matching rules, and move or rename approved files with a reversible operation log. Confirm setup: A Mac, the current Xcode toolchain and a documented permission checklist; distribution signing is a separate delivery task. 2. Phase 2 — Implement persistence and write-time invariants before decorating the UI: Store WatchedFolder, RuleVersion, FileFingerprint, PlannedAction and Receipt; exclude destination folders from reprocessing and detect name collisions before touching the source. 3. Phase 3 — Connect the working view to real saved state. Ask for each operating-system permission when its feature is used. Handle denial and revocation without a loop; show permission status and keep local history deletable. 4. Phase 4 — Expose the app-specific limits and recovery path in context: Default to dry-run and keep an undo map. Rules cannot execute arbitrary shell scripts initially; disappearing volumes and revoked folder permissions pause processing rather than deleting records. 5. Phase 5 — Walk through this concrete acceptance case and preserve its exported evidence: Drop a partially downloaded file, then finish it and create a same-name destination; wait for stability, preview the collision and never overwrite either file silently. Finish the README and backup/restore instructions; report unfinished capabilities explicitly. ## Paid-product capabilities outside this build - mature filesystem automation, rule depth, Apple integrations, and reliability - years of OS-version edge cases - large extension ecosystem - cross-device sync - commercial support and rapid compatibility fixes ## Implementation prompt Build the following focused alternative to Hazel. Implement the focused workflow below first; the verdict is not evidence of a completed or production-certified build. WORKING SLICE Watch a user-selected download folder, preview file-matching rules, and move or rename approved files with a reversible operation log. SETUP AND ARCHITECTURE Use Swift, SwiftUI/AppKit and SQLite on macOS, with secrets in Keychain where needed. Prerequisites: A Mac, the current Xcode toolchain and a documented permission checklist; distribution signing is a separate delivery task. Before integrating anything, record actual versions and permissions, plus model files or provider limits only where used, in the README; make unavailable dependencies visible rather than simulating success. DOMAIN MODEL AND INVARIANTS Store WatchedFolder, RuleVersion, FileFingerprint, PlannedAction and Receipt; exclude destination folders from reprocessing and detect name collisions before touching the source. IMPLEMENTATION CONTRACT Ask for each operating-system permission when its feature is used. Handle denial and revocation without a loop; show permission status and keep local history deletable. Provide an input/setup view, the main work view, and a review/export view appropriate to this workflow. Preserve the last saved state if a job or save fails. Include empty, loading, permission-denied, partial and retryable-error states. Log identifiers and error categories without secret values or unnecessary private content. APP-SPECIFIC BOUNDARY AND RECOVERY Default to dry-run and keep an undo map. Rules cannot execute arbitrary shell scripts initially; disappearing volumes and revoked folder permissions pause processing rather than deleting records. ACCEPTANCE SCENARIO Drop a partially downloaded file, then finish it and create a same-name destination; wait for stability, preview the collision and never overwrite either file silently. Also reopen the app after an interrupted operation, confirm the saved record/export remains inspectable, and document the recovery action. These are implementation acceptance requirements, not a claim that this guide has been tested. DELIVERY Deliver a runnable repository with migrations or project-format versioning, a non-sensitive example, environment/permission setup, the exact manual acceptance steps, and a backup/export-and-restore walkthrough. Implement the working slice before optional integrations; list any deferred paid-product capabilities honestly. Do not add capabilities outside the working slice just to resemble the original product. PROJECT RULES FOR AGENTS.md Keep the domain invariants above executable at the write boundary. Propose scope changes before adding providers or permissions. Never fabricate source evidence, publish results, identity matches or successful delivery. Preserve user originals and require an explicit confirmation for destructive changes or external publication. ## Completion evidence Demonstrate the prompt's acceptance scenarios against the scoped workflow. Include setup from a clean checkout and failure recovery. Check persistence across restart and export/restore only for the state the prompt says to store; for memory-only tools, confirm that temporary content is discarded as specified. Record actual results and remaining limitations. A detailed plan alone does not establish a working replacement.