# AGENTS.md — Build guide for TimeTac ## Project scope Record clock-in/out and project time, request leave and let a reviewer approve a versioned monthly timesheet export. Catalogue verdict: kinda. If you are one person logging hours against projects, this is a solved evening: a table, a timer, a CSV export, done. TimeTac is not sold for that, it is sold to companies that must prove who worked when, which in Spain means a daily time record that survives an inspection. An agent can absolutely build the clock-in screen, the leave calendar and the monthly timesheet PDF, and it will feel surprisingly complete. What it will not hand you is the tamper-resistant audit trail, the payroll and HR exports your accountant already accepts, and the phone app your field staff will actually open. So: yes for yourself, shaky the moment other people's paychecks depend on your SQLite file. 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 - Do not publish, spend money, contact customers, delete source data or run irreversible migrations without the project owner's authorization.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: TypeScript, React, Node and PostgreSQL with workspace membership enforced on the server. - Before starting: A PostgreSQL database, session authentication, two isolated example workspaces and private attachment storage. ## Stack and architecture - TypeScript, React, Node and PostgreSQL with workspace membership enforced on the server - Data design: Store Employee, WorkInterval, Break, ProjectAllocation, LeaveRequest and Approval; no overlapping open intervals and post-approval corrections create a visible amendment. - Setup: A PostgreSQL database, session authentication, two isolated example workspaces and private attachment storage ## Security and data integrity - Check membership on reads, mutations, attachments and exports. Keep activity history separate from editable current state; do not make private records public through search. - This is a time ledger, not automatic labor-law or payroll compliance. Document rounding, breaks and local policies explicitly; restrict individual records to authorized roles. - 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 Employee, WorkInterval, Break, ProjectAllocation, LeaveRequest and Approval; no overlapping open intervals and post-approval corrections create a visible amendment. - Project rule — scope and recovery: This is a time ledger, not automatic labor-law or payroll compliance. Document rounding, breaks and local policies explicitly; restrict individual records to authorized roles. - Project rule — acceptance: Clock out after midnight, allocate time to two projects and correct an approved entry; totals reconcile with the chosen timezone and the earlier approved export stays reproducible. - 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: [supabase-postgres-best-practices](https://github.com/supabase/agent-skills/blob/main/skills/supabase-postgres-best-practices/SKILL.md) — review this PostgreSQL domain schema, uniqueness constraints, transaction boundaries and access-scoped queries; Supabase hosting is not required. Follow the maintainer's installation instructions and match its requirements to the chosen runtime. - Recommended skill: [web-design-guidelines](https://github.com/vercel-labs/agent-skills/blob/main/skills/web-design-guidelines/SKILL.md) — review keyboard access, focus, validation, error recovery and the readable work/review interface or HTML report. 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: Record clock-in/out and project time, request leave and let a reviewer approve a versioned monthly timesheet export. - Share a synthetic example export and the acceptance walkthrough; keep real customer, health, financial and source data private: Clock out after midnight, allocate time to two projects and correct an approved entry; totals reconcile with the chosen timezone and the earlier approved export stays reproducible. - State the limits before asking someone to replace their existing tool: This is a time ledger, not automatic labor-law or payroll compliance. Document rounding, breaks and local policies explicitly; restrict individual records to authorized roles. ## Engineering roadmap 1. Phase 1 — Pin the working slice and create its example input: Record clock-in/out and project time, request leave and let a reviewer approve a versioned monthly timesheet export. Confirm setup: A PostgreSQL database, session authentication, two isolated example workspaces and private attachment storage. 2. Phase 2 — Implement persistence and write-time invariants before decorating the UI: Store Employee, WorkInterval, Break, ProjectAllocation, LeaveRequest and Approval; no overlapping open intervals and post-approval corrections create a visible amendment. 3. Phase 3 — Connect the working view to real saved state. Check membership on reads, mutations, attachments and exports. Keep activity history separate from editable current state; do not make private records public through search. 4. Phase 4 — Expose the app-specific limits and recovery path in context: This is a time ledger, not automatic labor-law or payroll compliance. Document rounding, breaks and local policies explicitly; restrict individual records to authorized roles. 5. Phase 5 — Walk through this concrete acceptance case and preserve its exported evidence: Clock out after midnight, allocate time to two projects and correct an approved entry; totals reconcile with the chosen timezone and the earlier approved export stays reproducible. Finish the README and backup/restore instructions; report unfinished capabilities explicitly. ## Paid-product capabilities outside this build - Legally defensible records: no tamper-evident log, no retention guarantees, nothing an inspector or works council will nod at - Native iOS and Android apps with GPS, offline clock-in and geofencing for people who are not at a desk - Hardware terminals and badge or fingerprint clock-in for shop floors - Payroll, ERP and HR integrations plus the export formats your bookkeeper already imports without complaining - Someone else owning uptime, overtime rule edge cases and the shift and break math for each country ## Implementation prompt Build the following focused alternative to TimeTac. This is a deliberately limited personal or small-team substitute, not parity with the paid service. WORKING SLICE Record clock-in/out and project time, request leave and let a reviewer approve a versioned monthly timesheet export. SETUP AND ARCHITECTURE Use TypeScript, React, Node and PostgreSQL with workspace membership enforced on the server. Prerequisites: A PostgreSQL database, session authentication, two isolated example workspaces and private attachment storage. 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 Employee, WorkInterval, Break, ProjectAllocation, LeaveRequest and Approval; no overlapping open intervals and post-approval corrections create a visible amendment. IMPLEMENTATION CONTRACT Check membership on reads, mutations, attachments and exports. Keep activity history separate from editable current state; do not make private records public through search. 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 This is a time ledger, not automatic labor-law or payroll compliance. Document rounding, breaks and local policies explicitly; restrict individual records to authorized roles. ACCEPTANCE SCENARIO Clock out after midnight, allocate time to two projects and correct an approved entry; totals reconcile with the chosen timezone and the earlier approved export stays reproducible. 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.