doc-currency

name	doc-currency
description	| Use when this capability is needed.

Documentation Currency skill

Documentation that lags the code is worse than no documentation — it actively misleads. Before you call a task done, make sure the docs catch up.

This skill is mandatory at task completion for any change that:

• Adds, removes, or restructures an authoritative module (observability, auth, persistence, copilot-sdk, MCP, telemetry exporters).
• Changes a public contract (route handler shape, env var, exported type, on-disk format).
• Changes the way another contributor would diagnose, configure, or extend the system.

Trivial fixes (single-file bugfix with no contract change, dependency bump, test-only edit) are exempt — you should still glance at the doc tree but no update is required.

Step 1 — Map the change to the docs that own it

Before editing anything, identify which authoritative docs describe the area you touched. The canonical owners in this repo are:

[!IMPORTANT] If your change touches an architectural boundary — auth, the Copilot worker dispatch, background jobs, storage, observability, Aspire resource graph — docs/architecture.md is in scope by default. It is the index doc that links everything else, so a drifted system diagram or stale code pointer there is louder than a stale rule in a deeper reference.

Area touched	Authoritative doc(s)
Architectural data flow, system shape, dev-loop story, anything cross-cutting	docs/architecture.md
OTel exporters, samplers, attributes, browser bootstrap, env vars	.github/skills/opentelemetry/SKILL.md
Aspire AppHost, resource graph, env injection, dev workflow	apphost.ts, docs/architecture.md (local-dev section), .github/skills/aspire-debugging/SKILL.md
Auth, multi-tenant token flow, per-request Octokit	docs/architecture.md (story), docs/architecture-multitenant.md (deep dive), .github/copilot-instructions.md
Copilot SDK sessions, MCP wiring, session persistence	docs/copilot-sdk-persistence.md, .github/skills/copilot-sdk/SKILL.md, .github/skills/copilot-sdk-worker-only/SKILL.md
Copilot worker boundary, per-user runtime pool, job executors	docs/architecture.md (decisions 2–4), .github/skills/copilot-sdk-worker-only/SKILL.md
Per-user storage layout, token store envelope, retention sweeps	docs/architecture.md (storage section), docs/architecture-multitenant.md
Deployment to Azure Container Apps	docs/deployment-aca.md, infra/README.md
Documentation rules themselves	.github/instructions/documentation.instructions.md
TypeScript conventions, anti-patterns	.github/instructions/typescript.instructions.md
Testing patterns (Vitest, Playwright)	.github/instructions/testing.instructions.md
Architectural data flow, environment variables, commands	.github/copilot-instructions.md, docs/architecture.md
Tech-debt tooling, scripts	.github/copilot-instructions.md
User-facing setup, dev-loop commands	README.md, docs/architecture.md (local-dev section), CONTRIBUTING.md

If your change spans more than one row, every owning doc is in scope.

Step 2 — Diff the docs against the code

For each owning doc:

1. Open the doc.
2. Search for any specific fact that the change could have invalidated:
   • File paths and module names (renames, deletes).
   • Env var names and defaults.
   • Span/metric/attribute names.
   • Exported function signatures and the rules around them.
   • Step-by-step procedures (install, smoke test, debug recipes).
   • The "Red flags" or "Anti-patterns" tables — does today's change add a new one?
3. If the doc claims something that is no longer true, update it.
4. If the change introduces a new pattern that future contributors will need to follow, add it.

Treat omissions with as much weight as contradictions. If the doc should say "we do X" and now doesn't, that's a gap.

Step 3 — Keep the writing proportional

Doc updates follow the same proportionality as TSDoc:

• Prefer a small, surgical change to the right section over a large new section.
• A new rule or fact is worth one or two sentences in the relevant table or rule — not a whole subsection unless it materially changes a workflow.
• Cross-link rather than duplicate. If a rule lives in documentation.instructions.md, link to it from the skill, don't restate it.
• Update the "Custom metrics registry" table when adding a metric — that's literally why it exists.

Step 3a — Evergreen, not blow-by-blow

Documentation captures the current state of the system, not the history of how it got there. A reader coming to the docs for the first time does not need to know what we tried before, what regression we recovered from, or which commit introduced a rule. They need to know what is true today and what they must do to stay aligned with it.

Anti-patterns to avoid in docs:

• ❌ "Yesterday we discovered that…" / "In commit X we changed…" / "We used to do Y but now…"
• ❌ Lists of phases, attempts, or migration notes that the codebase no longer references.
• ❌ Verbatim copies of session transcripts, rubber-duck critiques, or chat history.
• ❌ "Previously, this worked because…" — if it doesn't work that way now, drop the previous explanation.

What to write instead:

• ✅ "We do X because Y." (Present tense. Active voice. Current reality.)
• ✅ "Don't do Z — it causes W." (Concrete invariant the reader needs.)
• ✅ "See path/file.ts:N for the implementation." (Pointer the reader can verify.)

Migration notes have a legitimate but narrow place: when a new pattern replaces an old one that still appears in the codebase so readers recognise the deprecated form and can finish the migration. Once the old form is gone, the migration note goes with it.

If today's change unwinds an earlier approach, remove the earlier explanation rather than layering a "but now we do…" paragraph on top of it. The doc tree is not append-only.

Step 4 — Verify

After updating docs:

• Re-read each updated section in isolation. Does it still parse without the surrounding context the author had in their head?
• Check internal links (grep for ](../ paths if you've moved files).
• For the OTel skill specifically, re-walk the "Rules" list — any rule that no longer matches current code is now misleading.

Step 5 — Commit the docs with the code, not separately

Doc updates belong in the same PR (and ideally same commit) as the code change. A doc-only follow-up PR routinely never lands. If the code commit is already pushed and you discover a gap, push a focused follow-up immediately — don't queue it.

What this skill is not

• It is not a license to write speculative documentation for code you didn't change.
• It is not a sweep of the entire doc tree on every commit. Map → diff → update.
• It is not a substitute for inline TSDoc — both matter, at different levels.

Self-check before task_complete

• I identified every authoritative doc that owns an area I touched.
• For each, I diffed it against my change and updated specifics that drifted.
• New patterns/rules introduced by my change are documented.
• Doc updates are in the same PR (and committed) as the code.
• Internal links and tables (metrics registry, attribute tables) are current.

If any box is unticked, the task is not complete.

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Source: chrisreddington/flight-school — distributed by TomeVault.