# AGENTS.md — Build guide for Instatus ## Project scope Host a status page separately from the monitored app, manage components and post incident updates with confirmed-subscriber notifications. Catalogue verdict: kinda. The page itself is the easy part: components, colored dots, an incident timeline, a 90 day uptime bar; an agent will hand you that in an afternoon. The notification fan-out is where it gets annoying: email is a Resend account and a loop, but you inherit double opt-in, unsubscribes, bounce handling, and explaining why the incident email landed in spam during the outage. Hosting is the other half: a status page on the same infra as the thing it reports on is decoration, so you need a separate host and domain and the discipline to keep it boring. Add the workflow Instatus quietly gives you, writing an update from your phone at 2am, per-component subscriber preferences, Slack and RSS and webhooks. Buildable in a weekend for a personal project; not the thing to hand-roll if a real customer contract mentions the words 'status page'. 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 - Do not publish, spend money, contact customers, delete source data or run irreversible migrations without the project owner's authorization.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, SQLite, a bounded scheduled worker and a read-only status dashboard. - Before starting: An always-on host, explicit allowed targets, an alert destination and synthetic healthy/failing response fixtures. ## Stack and architecture - TypeScript, Node, SQLite, a bounded scheduled worker and a read-only status dashboard - Data design: Store Component, Incident, IncidentUpdate, Subscription and NotificationReceipt; component status derives from open incidents/manual overrides and gaps are separate from uptime success. - Setup: An always-on host, explicit allowed targets, an alert destination and synthetic healthy/failing response fixtures ## Security and data integrity - Persist samples, incident transitions and notification receipts. Missing samples are gaps rather than success; apply hysteresis and keep alert state across restarts. Run the checker separately from the monitored service. - Start with manual incidents plus an optional basic checker. Do not fabricate historical uptime or imply a public status page replaces operational monitoring; notification provider failures need visible retries. - 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 Component, Incident, IncidentUpdate, Subscription and NotificationReceipt; component status derives from open incidents/manual overrides and gaps are separate from uptime success. - Project rule — scope and recovery: Start with manual incidents plus an optional basic checker. Do not fabricate historical uptime or imply a public status page replaces operational monitoring; notification provider failures need visible retries. - Project rule — acceptance: Publish an outage, update its scope, resolve it and replay a notification job; the timeline stays ordered and confirmed subscribers receive each update once where receipts permit. - 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: Host a status page separately from the monitored app, manage components and post incident updates with confirmed-subscriber notifications. - Share a synthetic example export and the acceptance walkthrough; keep real customer, health, financial and source data private: Publish an outage, update its scope, resolve it and replay a notification job; the timeline stays ordered and confirmed subscribers receive each update once where receipts permit. - State the limits before asking someone to replace their existing tool: Start with manual incidents plus an optional basic checker. Do not fabricate historical uptime or imply a public status page replaces operational monitoring; notification provider failures need visible retries. ## Engineering roadmap 1. Phase 1 — Pin the working slice and create its example input: Host a status page separately from the monitored app, manage components and post incident updates with confirmed-subscriber notifications. Confirm setup: An always-on host, explicit allowed targets, an alert destination and synthetic healthy/failing response fixtures. 2. Phase 2 — Implement persistence and write-time invariants before decorating the UI: Store Component, Incident, IncidentUpdate, Subscription and NotificationReceipt; component status derives from open incidents/manual overrides and gaps are separate from uptime success. 3. Phase 3 — Connect the working view to real saved state. Persist samples, incident transitions and notification receipts. Missing samples are gaps rather than success; apply hysteresis and keep alert state across restarts. Run the checker separately from the monitored service. 4. Phase 4 — Expose the app-specific limits and recovery path in context: Start with manual incidents plus an optional basic checker. Do not fabricate historical uptime or imply a public status page replaces operational monitoring; notification provider failures need visible retries. 5. Phase 5 — Walk through this concrete acceptance case and preserve its exported evidence: Publish an outage, update its scope, resolve it and replay a notification job; the timeline stays ordered and confirmed subscribers receive each update once where receipts permit. Finish the README and backup/restore instructions; report unfinished capabilities explicitly. ## Paid-product capabilities outside this build - Deliverability someone else warms up and monitors: your first incident email is also your first send reputation test - Notification channels beyond email: SMS, Slack app, Teams, Discord, native webhooks, RSS, all of which Instatus ships out of the box - Per-component subscriptions, unsubscribe handling, and double opt-in that you do not have to think about - The polish: scheduled maintenance windows, incident templates, timezone handling, embeddable widgets, public API - Real independence, unless you actually do the work to host the page away from your own stack ## Implementation prompt Build the following focused alternative to Instatus. This is a deliberately limited personal or small-team substitute, not parity with the paid service. WORKING SLICE Host a status page separately from the monitored app, manage components and post incident updates with confirmed-subscriber notifications. SETUP AND ARCHITECTURE Use TypeScript, Node, SQLite, a bounded scheduled worker and a read-only status dashboard. Prerequisites: An always-on host, explicit allowed targets, an alert destination and synthetic healthy/failing response fixtures. 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 Component, Incident, IncidentUpdate, Subscription and NotificationReceipt; component status derives from open incidents/manual overrides and gaps are separate from uptime success. IMPLEMENTATION CONTRACT Persist samples, incident transitions and notification receipts. Missing samples are gaps rather than success; apply hysteresis and keep alert state across restarts. Run the checker separately from the monitored service. 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 Start with manual incidents plus an optional basic checker. Do not fabricate historical uptime or imply a public status page replaces operational monitoring; notification provider failures need visible retries. ACCEPTANCE SCENARIO Publish an outage, update its scope, resolve it and replay a notification job; the timeline stays ordered and confirmed subscribers receive each update once where receipts permit. 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.