Files
tiny-pattern-ts/AGENTS.md
T
tmu 8efd13b2f4 ✨ Add branch front-door command
The branching model assumed a clean, current `main` and a green baseline
before any edit, but both were prose, and prose nobody checks silently
becomes a suggestion. `npm run branch -- <prefix>/<desc>` asserts the
precondition and only then creates the branch, so a later failure is
attributable to the change that caused it.

Checks run cheap-first (`--porcelain` deliberately catches untracked
files, which would otherwise ride onto the new branch) and the suite
runs last, so an ineligible tree never pays for it. `main`'s remote is
derived from its upstream rather than hardcoded: this repo has both
`origin` and `origin_https`, and `main` tracks the latter, so a
`git fetch origin main` currency check would compare against a ref that
is never updated here. The baseline runs after switching to `main`, so a
red `main` restores the starting branch instead of stranding the caller
on it.

The prefix stays a judgment call: the script validates it against the
documented vocabulary instead of inferring it.

Prose kept as index only — AGENTS.md points agents at the command from
the task workflow, CONTRIBUTING.md owns the model and the bare-script
tier (dropping its stale hardcoded count of "two" conveniences).
2026-09-08 22:14:34 +02:00

6.9 KiB

AGENTS.md

Machine entry point for AI coding agents working in this repo. The authoritative guidance for humans lives in CONTRIBUTING.md and README.md; this file only points at it and states the stable first-action facts. Do not restate evolving prose here — it will drift.

First action

  • Project: F#-style pattern matching for TypeScript/ESM. Node >=26 (pinned via .node-version), ESM-only (no CommonJS shim).

  • While iterating: npm run test (check:tsc + the unit suite) for fast feedback on the files you changed.

  • Optional code intelligence: this repo installs @spences10/pi-lsp (pinned in .pi/settings.json) as a project-local pi extension. It talks to the repo's own TypeScript 7 via tsc --lsp --stdio and exposes read-only tools — lsp_hover, lsp_definition, lsp_references, lsp_find_symbol, lsp_document_symbols, lsp_diagnostics(_many). Prefer lsp_references over grep -w for widely-colliding identifiers (matches, type, …); use lsp_hover to read inferred types on generic-heavy code. It has no rename / code-action / apply-edit surface — the write side is pi's edit tool + check:tsc. Treat empty LSP output as inconclusive, not success: npm run test / npm run verify remain the sole authoritative gate (see the next bullet).

  • Definition of done — run this before you call the work finished: npm run verify. If all green, commit. If red, look at the output, fix the root cause, and re-run.

  • On commit: write a good message (see CONTRIBUTING.md § Commit messages). Lefthook's pre-commit hook already runs the fast, offline, staged-file checks — don't run them by hand. If the hook fails on style, npm run fix, restage, recommit.

  • npm run maintain is NOT part of the feature loop. Its scans are advisory, never a gate; run them only on an explicit maintenance / update-deps branch.

    npm run test    # while iterating (fast feedback)
    npm run verify  # definition of done: whole-project correctness, one shot
    

Never do

Don't silence the type system to force a green run. As an agent these are forbidden:

  • // @ts-nocheck, // @ts-ignore, // @ts-expect-error
  • // oxlint-disable / // oxlint-disable-next-line
  • as casts used to push an expression through (type-aware oxlint already flags unsafe assertions)

Fix the root cause with the type system instead — narrowing, generics, satisfies, conditional / mapped types, utility types (NonNullable, Exclude, …). TypeScript can express it; that's the intended tool. The oxlint-disable-location rule in CONTRIBUTING.md § Rules the tools don't enforce is a human last-resort convention (so a reviewer can spot a deliberate suppression) — it is not permission for you to add one. If the types genuinely cannot express something, stop and surface the conflict (commit message / handover) rather than suppress it.

The same applies to the checks themselves: never git commit --no-verify (or otherwise skip a pre-commit / pre-push hook). The checks are fast and offline, so a redundant run is fine — bypassing a hook to get green is the identical anti-pattern. If a commit already skipped a hook, redo it through one: git reset --soft HEAD~1 && git commit -C <skipped-sha>.

Never start a long-lived / blocking process such as npm run watch. It runs until a human stops it with Ctrl-C, so in an agent turn it hangs forever and floods the context with continuous output. Reach for a one-shot command instead — npm run test (or npm run check) — to get feedback.

Backlog

backlog.tasks uses the vscode-todotasks format (not Markdown). A line ending in : is a project; every other line is a task. Status glyphs: ☐ open, ✔ done, ✘ cancelled; subtasks nest by indentation. Inline @tags carry metadata — @done / @cancelled mark completion, @critical / @high / @low / @today set priority. The (…) timestamp after @done is editor-generated: omit it when checking off by hand.

Required coupling: a ✔ line must also carry @done, and a ✘ line must carry @cancelled. The sandy081.todotasks extension treats the glyph as the completion signal, then unconditionally searches for the matching tag to decorate; a bare ✔/✘ with no tag makes it compute an illegal Range (negative character offset) that throws and kills all highlighting/decoration for the document. A ☐ may stand alone. So check off by hand as ✔ … @done (optionally @done (timestamp)), never a lone ✔.

Working on tasks

  • Task with subtasks (a task that has indented children): create the branch with npm run branch -- <prefix>/<desc>, inferring the prefix from the task content (feature/… / fix/… / chore/…) — do not hand-write git switch -c, the command enforces the clean-tree / current-main / green-baseline precondition. Work on each subtask with commits, then present a concise handover for the user to review. Use this fixed shape:

    ## Handover — <branch>
    
    **Implemented:** <what was built, and how>
    **Judgement calls:** <where the task was unclear, and what you assumed>
    **Known problems:** <open issues, caveats, follow-ups>
    

    Once the user has no further objections, merge back: git checkout main && git merge --no-ff <branch>. The branching model is documented in CONTRIBUTING.md § Branching model.

  • Leaf task (no indented children): implement on the current branch and commit.

In both cases, follow CONTRIBUTING.md § Testing discipline (type-driven). Each subtask gets one or more commits.

Read these