hemx/AGENTS.md

# hemx — AGENTS.md

## Purpose

This file tells coding agents how to work in this repository. It is a durable operating contract, not a generated inventory.

Keep it stable. Prefer pointers to canonical sources over copied structure, file lists, metrics, architecture maps, command inventories, or status snapshots.

## Agent workflow

- Start from product intent and requirements; inspect code only after the target behavior is clear.
- Read `REQUIREMENTS.md` before changing behavior.
- If behavior changes, update `REQUIREMENTS.md` in the same change.
- If implementation work does not change durable product obligations, acceptance, safety/recovery behavior, or verification duties, say `REQUIREMENT IMPACT: none` in the handoff and why.
- Cite relevant requirements in code, tests, or docs as `req: <component>/001`.
- Do not add citation-only padding to satisfy tooling; cite only where the requirement constrains the text.
- Use requirement tags consistently: stable area tags like `[parser]`, `[auth]`, `[ui]`; temporary planning tags like `[bootstrap]`, `[mvp]`, or `[milestone-1]` only while they are useful.
- Run `redgate list`, `redgate refs`, and `redgate health` when requirements change; include `redgate lint` when the change is meant to reduce requirement maintainability warnings.

## Git workflow

- Commit complete, coherent slices only; do not commit broken work or temporary debug output.
- Use Conventional Commits: `type(scope): summary`.
- Keep commit subjects readable; requirement IDs do not have to be in the subject.
- Every behavior-changing or requirement-changing commit should cite relevant requirement IDs in the commit body or trailers using `req: <component>/001`.
- Use commit history for evolution: `git log --grep 'req: parser/012'` should find the commits that changed that behavior.
- Use the current tree for state: `REQUIREMENTS.md`, citations, tests, and `redgate health` describe what is true now.
- Before committing requirement or behavior changes, run relevant tests and `redgate health --strict`.

## Requirements-first TDD

- Write requirements as desired behavior, not as a snapshot of current behavior.
- Keep each requirement row to one checkable obligation; split oversized examples, escape hatches, or negative cases into separate stable IDs while preserving the original ID's main intent.
- First split intent into broad error classes: what can go wrong, and what outcome must hold.
- Test the largest risky classes before narrow examples.
- Add adversarial tests for malformed, hostile, ambiguous, missing, duplicated, and boundary inputs.
- Do not over-codify existing behavior while direction is still moving.
- Add narrow concrete tests only after requirements converge into a stable direction.

## Redgate CLI

- `redgate list` — show requirements as TSV.
- `redgate refs` — show `req:` citations found in the repo.
- `redgate health` — show uncited requirements, duplicate IDs, and stale citations.
- `redgate lint` — show maintainability warnings such as missing rings and oversized requirement rows.
- `redgate health --strict` — fail on hard errors: empty requirements, duplicate IDs, or stale citations.
- `redgate agents` — print this starter template; review, shrink, and edit before committing.

## Local guidance

- Add only durable style, ownership, gotchas, and at most a few stable commands agents should actually run.
- Prefer links or pointers to canonical sources over copied lists.
- Avoid project trees, architecture maps, generated inventories, current file sizes, issue lists, TODO inventories, and other snapshots that will rot.
- Stable commands: `cargo run -p hemx-xtask -- test`, `cargo run -p hemx-xtask -- html-examples-smoke`, `cargo check --workspace`, `redgate health --strict`. Use the xtask runner for full verification so jobs are capped from local CPU and memory; use the html_examples smoke for focused browser verification of the HTML pattern gallery. req: test/004 req: test/006
- Example behavior tests should prefer `hemx_test` generated-resource assertions over raw slot constants or raw effect/payload matching. req: test/008
- Run the workout product exemplar with `cargo run -p hemx-xtask -- workout dev` and open `http://127.0.0.1:3028`; set `HEMX_WORKOUT_ADDR=127.0.0.1:3030` if the default port is busy. Its durable visual direction and recovery expectations live in `examples/workout/DESIGN.md`. req: examples/008
- Use the same Workout command surface for tests, production build, and mobile release: `cargo run -p hemx-xtask -- workout test`, `cargo run -p hemx-xtask -- workout build`, `HEMX_WORKOUT_ORIGIN=https://workout.example.com cargo run -p hemx-xtask -- workout mobile-release`, and `HEMX_WORKOUT_ORIGIN=https://workout.example.com cargo run -p hemx-xtask -- workout mobile-verify`; Android/iOS SDKs, store submission targets, and signing remain external blockers, not repo-owned secrets. req: examples/006
- hemx core stays small: effects, typed ids, registries, and wire schema only.
- Routing, auth, sessions, transport, transitions, sync, and storage belong in integration/user crates.
- Public examples and beginner APIs should use generated resources and `IntoEffect`, not raw ids or runtime opcodes.
- `examples/html_examples` is the copy-paste HTML pattern gallery for htmx-style examples; keep exact htmx URL slugs visible while translating behavior to boring `.heml`, generated resources, and server-owned Rust state. req: htmx_equivalents/001 req: htmx_equivalents/005 req: examples/007
- Use `cargo run -p hemx-xtask -- app new PATH` for the generic page/form/keyed-row/notice starter, and `cargo run -p hemx-xtask -- app new --mobile PATH` for the phone-first starter with host capabilities, recovery truth, and release-kit commands. req: ceremony/005 req: ceremony/006
- The public component-reuse explanation lives in `docs/recipes/reusable-partials.md`; do not grow a client component framework to explain partial composition.
- The stable public `.heml` authoring surface lives in `docs/hemplate-syntax.md`; Hemlate examples must use that real hemplate syntax, not Vue/Handlebars sketches.
- Optional `.heml` editor overlays must share authority with `hemx-build` diagnostics and `docs/hemplate-syntax.md`; `hemx-lsp` owns editor protocol glue for diagnostics/completion/hover and derive-known template facts, while VS Code/Cursor/Neovim keep normal HTML/tree-sitter tooling. Do not create a second template language, selector model, formatter, Rust type system, or custom editor framework. req: diagnostics/004 req: diagnostics/005 req: diagnostics/006
- JS runtime changes must preserve root-scoped lookup, fail-closed request handling, root-scoped error outlets, and tiny pending/failure/trigger-timing conventions without selectors, VDOM, expressions, or per-node listeners. req: runtime/005 req: convention/001 req: convention/003 req: convention/005 req: convention/007
- Host capability adapters must stay at the `hemx-host` boundary: they may call host APIs and return host events, but they must not mutate DOM or own app/domain state. req: host/002
- Local/offline app behavior should be commands/events/projections; do not add `hemx-local`, stored DOM patches, or stored `EffectBatch` truth without a proven reusable contract. req: local/001 req: local/002
- Axum apps should serve and load the shared runtime through hemx-axum helpers such as `runtime_js_path()` and `runtime_js()`, not hard-coded `/hemx.js` URLs or app-owned cache-busting strings.