# AGENTS.md — Build guide for Sentry ## Project scope Accept bounded application-error events, group similar failures, attach release IDs and alert on first-seen or regressed issue groups for one team. Catalogue verdict: kinda. The core loop is buildable, but a dependable replacement becomes a real weekend or multi-day project. For Sentry, receive bounded error events, group them, link releases, and notify one team. The hard boundary is sdk ecosystem, grouping models, tracing, replay, global ingestion, and enterprise operations, plus independent infrastructure and reliable alerting. 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 - Do not publish, spend money, contact customers, delete source data or run irreversible migrations without the project owner's authorization.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, Node, Express, better-sqlite3 and a durable ingestion/alert worker with an authenticated server-rendered issue dashboard. - Before starting: An HTTPS intake URL, private administrator access, two disposable project tokens, explicit byte/event quotas and retention, a configured alert channel, and synthetic duplicate, malformed, secret-bearing and release-regression events. ## Stack and architecture - TypeScript, Node, Express, better-sqlite3 and a durable ingestion/alert worker with an authenticated server-rendered issue dashboard - Data design: Store Project, HashedProjectToken, SanitizedEvent, IngestReceipt, FingerprintVersion, IssueGroup, Release and AlertOutbox; deduplicate event IDs within the project, keep grouping stable across volatile request IDs, and reopen only an explicitly resolved group when a matching error recurs. - Setup: An HTTPS intake URL, private administrator access, two disposable project tokens, explicit byte/event quotas and retention, a configured alert channel, and synthetic duplicate, malformed, secret-bearing and release-regression events ## Security and data integrity - Authenticate intake with hashed, rotatable project-scoped tokens and derive the project from the token. Cap payload bytes, stack frames, properties and per-project intake before accepting work. Allowlist and redact fields before queueing, storage or logging; reject malformed events without recording their contents. Deduplicate by project and event ID, retaining the original receipt on retry. Group sanitized events with a versioned fingerprint excluding volatile IDs. In one transaction, mark the queued event processed, update its issue/release state and enqueue one alert per first-seen or resolved-to-regressed transition. Lease pending jobs across worker restarts; retain uncertain notification delivery for review instead of blindly sending again. Intake tokens grant no dashboard access; authenticated administrators can resolve groups and review alert status. - Use a documented small JSON intake protocol and sample sender, not an unsupported claim of Sentry SDK compatibility. Strip credentials and private request bodies before storage. Start without session replay or arbitrary source-map downloads; quotas, retention, release ordering and grouping heuristics remain explicit limitations. - 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 Project, HashedProjectToken, SanitizedEvent, IngestReceipt, FingerprintVersion, IssueGroup, Release and AlertOutbox; deduplicate event IDs within the project, keep grouping stable across volatile request IDs, and reopen only an explicitly resolved group when a matching error recurs. - Project rule — scope and recovery: Use a documented small JSON intake protocol and sample sender, not an unsupported claim of Sentry SDK compatibility. Strip credentials and private request bodies before storage. Start without session replay or arbitrary source-map downloads; quotas, retention, release ordering and grouping heuristics remain explicit limitations. - Project rule — acceptance: Replay one event ID and send the same stack under a second ID; store two occurrences in one group. Resolve it, send the error in a new release and restart its worker; record one regression transition and one alert intent. Invalid tokens and oversized/malformed payloads are rejected, while a secret-bearing fixture is redacted before durable storage. - 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: [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. - Recommended skill: [sharp-edges](https://github.com/trailofbits/skills/blob/main/plugins/sharp-edges/skills/sharp-edges/SKILL.md) — review configuration and API defaults against the app-specific invariants and recovery boundaries above; this is not a security certification. 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: Accept bounded application-error events, group similar failures, attach release IDs and alert on first-seen or regressed issue groups for one team. - Share a synthetic example export and the acceptance walkthrough; keep real customer, health, financial and source data private: Replay one event ID and send the same stack under a second ID; store two occurrences in one group. Resolve it, send the error in a new release and restart its worker; record one regression transition and one alert intent. Invalid tokens and oversized/malformed payloads are rejected, while a secret-bearing fixture is redacted before durable storage. - State the limits before asking someone to replace their existing tool: Use a documented small JSON intake protocol and sample sender, not an unsupported claim of Sentry SDK compatibility. Strip credentials and private request bodies before storage. Start without session replay or arbitrary source-map downloads; quotas, retention, release ordering and grouping heuristics remain explicit limitations. ## Engineering roadmap 1. Phase 1 — Pin the working slice and create its example input: Accept bounded application-error events, group similar failures, attach release IDs and alert on first-seen or regressed issue groups for one team. Confirm setup: An HTTPS intake URL, private administrator access, two disposable project tokens, explicit byte/event quotas and retention, a configured alert channel, and synthetic duplicate, malformed, secret-bearing and release-regression events. 2. Phase 2 — Implement persistence and write-time invariants before decorating the UI: Store Project, HashedProjectToken, SanitizedEvent, IngestReceipt, FingerprintVersion, IssueGroup, Release and AlertOutbox; deduplicate event IDs within the project, keep grouping stable across volatile request IDs, and reopen only an explicitly resolved group when a matching error recurs. 3. Phase 3 — Connect the working view to real saved state. Authenticate intake with hashed, rotatable project-scoped tokens and derive the project from the token. Cap payload bytes, stack frames, properties and per-project intake before accepting work. Allowlist and redact fields before queueing, storage or logging; reject malformed events without recording their contents. Deduplicate by project and event ID, retaining the original receipt on retry. Group sanitized events with a versioned fingerprint excluding volatile IDs. In one transaction, mark the queued event processed, update its issue/release state and enqueue one alert per first-seen or resolved-to-regressed transition. Lease pending jobs across worker restarts; retain uncertain notification delivery for review instead of blindly sending again. Intake tokens grant no dashboard access; authenticated administrators can resolve groups and review alert status. 4. Phase 4 — Expose the app-specific limits and recovery path in context: Use a documented small JSON intake protocol and sample sender, not an unsupported claim of Sentry SDK compatibility. Strip credentials and private request bodies before storage. Start without session replay or arbitrary source-map downloads; quotas, retention, release ordering and grouping heuristics remain explicit limitations. 5. Phase 5 — Walk through this concrete acceptance case and preserve its exported evidence: Replay one event ID and send the same stack under a second ID; store two occurrences in one group. Resolve it, send the error in a new release and restart its worker; record one regression transition and one alert intent. Invalid tokens and oversized/malformed payloads are rejected, while a secret-bearing fixture is redacted before durable storage. Finish the README and backup/restore instructions; report unfinished capabilities explicitly. ## Paid-product capabilities outside this build - SDK ecosystem, grouping models, tracing, replay, global ingestion, and enterprise operations - global probe network - phone and SMS delivery - massive retention - advanced incident response and support ## Implementation prompt Build the following focused alternative to Sentry. This is a deliberately limited personal or small-team substitute, not parity with the paid service. WORKING SLICE Accept bounded application-error events, group similar failures, attach release IDs and alert on first-seen or regressed issue groups for one team. SETUP AND ARCHITECTURE Use TypeScript, Node, Express, better-sqlite3 and a durable ingestion/alert worker with an authenticated server-rendered issue dashboard. Prerequisites: An HTTPS intake URL, private administrator access, two disposable project tokens, explicit byte/event quotas and retention, a configured alert channel, and synthetic duplicate, malformed, secret-bearing and release-regression events. 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 Project, HashedProjectToken, SanitizedEvent, IngestReceipt, FingerprintVersion, IssueGroup, Release and AlertOutbox; deduplicate event IDs within the project, keep grouping stable across volatile request IDs, and reopen only an explicitly resolved group when a matching error recurs. IMPLEMENTATION CONTRACT Authenticate intake with hashed, rotatable project-scoped tokens and derive the project from the token. Cap payload bytes, stack frames, properties and per-project intake before accepting work. Allowlist and redact fields before queueing, storage or logging; reject malformed events without recording their contents. Deduplicate by project and event ID, retaining the original receipt on retry. Group sanitized events with a versioned fingerprint excluding volatile IDs. In one transaction, mark the queued event processed, update its issue/release state and enqueue one alert per first-seen or resolved-to-regressed transition. Lease pending jobs across worker restarts; retain uncertain notification delivery for review instead of blindly sending again. Intake tokens grant no dashboard access; authenticated administrators can resolve groups and review alert status. 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 Use a documented small JSON intake protocol and sample sender, not an unsupported claim of Sentry SDK compatibility. Strip credentials and private request bodies before storage. Start without session replay or arbitrary source-map downloads; quotas, retention, release ordering and grouping heuristics remain explicit limitations. ACCEPTANCE SCENARIO Replay one event ID and send the same stack under a second ID; store two occurrences in one group. Resolve it, send the error in a new release and restart its worker; record one regression transition and one alert intent. Invalid tokens and oversized/malformed payloads are rejected, while a secret-bearing fixture is redacted before durable storage. 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.