# Project Guidelines

## Essential rules

### Spec Generation Hygiene

- Do not cite `.fusion/tasks/<id>/<file>` paths in Context/Steps/File Scope unless the file already exists, is explicitly created as a `(new)` Artifact, or is sibling `PROMPT.md`/`task.json`/`attachments/*`.
- Dangling task-local file references are a blocking spec REVISE.
- Save planning scratch and interim notes via `fn_task_document_write` instead of inventing on-disk task-local files.

#### External-integration evidence

Any task integrating a third-party tool (CLI, daemon, downloadable binary, installer-managed dependency) must cite, in PROMPT.md:
1. Canonical upstream repo URL.
2. Docs/homepage URL.
3. Release/download URL.
4. Binary/CLI name in backticks.
5. Checksum or `upstream-pending-verification` marker.

Missing evidence is a blocking REVISE. Never invent release URLs, binary names, or hashes.

Example evidence section shape:

```markdown
## External Integration Evidence

- Canonical upstream repo URL: https://github.com/max-sixty/worktrunk
- Docs / homepage URL: https://worktrunk.dev/
- Release / download URL: https://github.com/max-sixty/worktrunk/releases/latest/download/wt-linux-x64.tar.gz
- Binary / CLI name: `wt`
- Checksum: `sha256-<digest>` (or `upstream-pending-verification` until the checksum is pinned)
```

See `docs/contributing.md` for the fuller spec-authoring guidance and accepted labeled layout variants.

### Finalizing Changes

When a change affects published `@runfusion/fusion`, add a changeset (example: `.changeset/<name>.md` with `"@runfusion/fusion": patch`).

Bump types:
- **patch** — bug fixes/internal
- **minor** — new features/CLI/tools
- **major** — breaking changes

Do **NOT** create changesets for AGENTS.md/README/internal docs, CI config, or behavior-preserving refactors. `@fusion/core`, `@fusion/dashboard`, and `@fusion/engine` are private.

### Releasing

Use only:

```bash
pnpm release --yes
```

`scripts/release.mjs` is the source of truth. Do not substitute with manual `changeset version`, `pnpm publish`, or git tags.

### Package Structure

- `@fusion/core` — domain model/task store (private)
- `@fusion/dashboard` — web UI + API server (private)
- `@fusion/engine` — triage/executor/reviewer/merger/scheduler (private)
- `@runfusion/fusion` — CLI + pi extension (published)

Only `@runfusion/fusion` is published; `@fusion/*` packages are bundled into it.

#### Importing across `@fusion/*` packages

`@fusion/*` imports must be statically analyzable. Anti-pattern:

```ts
const engineModule = "@fusion/engine";
const engine = await import(/* @vite-ignore */ engineModule);
```

Rules:
1. Default to static imports.
2. `@fusion/core` uses DI (`setCreateFnAgent`) instead of dynamic `import("@fusion/engine")` due to circularity.
3. Never reintroduce the `engineModule = "@fusion/engine"` trick.
4. `vi.mock("@fusion/engine", ...)` remains valid.

### Testing commands

The merge gate is thin and trusted: CI blocks PRs on exactly Lint, Typecheck, Build, and Gate (boot smoke + `pnpm test:gate`). Everything else runs non-blocking in `full-suite.yml` on push to main. A red gate means a real problem; a red non-blocking run is information, not a merge stopper. Typechecks/manual checks are not substitutes for the gate.

```bash
pnpm test          # gate suite + changed-only affected tests (bounded; never full-suite)
pnpm test:gate     # the merge gate: curated engine-core suite + CI-shape test
pnpm smoke:boot    # boot smoke: CLI --help + real serve /api/health
pnpm test:velocity # weekly report-only test velocity baseline; use -- --measure --write-report to refresh
pnpm test:full     # full workspace suite — explicit opt-in only
pnpm lint
pnpm build
pnpm verify:workspace  # deep opt-in verification (lint -> test:full -> build); NOT the merge gate
```

### Standing Rule: Flaky Tests Are Quarantined on Sight (Deletion Ratchet)

- A test observed failing without a corresponding real bug in the change is QUARANTINED ON SIGHT: add an entry to `scripts/lib/test-quarantine.json` (`file`, `reason` with a link to the failing run, `quarantinedAt`) AND a matching one-line `exclude` in that package's vitest config, in the same commit.
- **Agents must never appease a flaky test.** No widened timeouts, no added retries, no loosened or deleted assertions to make a flake pass. Quarantine it instead. Appeasement drains the test's signal and is how the suite rotted last time.
- A quarantined test is DELETED after 14 days (`quarantinedAt` + 2 weeks) unless rescued. Rescue requires evidence the test catches real regressions plus a root-cause fix — not stabilization passes.
- A flake INSIDE the merge gate is evicted, not skipped: remove its line from the `engine-core` allow-list in `packages/engine/vitest.config.ts` (the eviction PR does not need the flaky test to pass).
- A second quarantine in the same subsystem is a product-race smell — look at the product code before the deletion clock runs out (see `docs/solutions/ui-bugs/skill-autocomplete-highlight-reset-on-swr-revalidation.md`: a flake "stabilized" three times was a real race).
- Gate admission requires evidence of value; tests never graduate into the gate by default. Mechanics: `docs/testing.md` → "Quarantine ledger and the deletion ratchet".

### Standing Rule: Do Not Add Slow Tests (FN-5048)

- Prefer narrow seams, in-memory fakes, shared harnesses, and targeted assertions.
- Prefer fake timers over real polling/time waits.
- Do not mask slowness by raising worker/concurrency knobs.
- Do not add new real-network calls, real polling loops, or mock-the-world shells when a narrower seam exists.
- Use the testing taxonomy in `docs/testing.md` when deciding trim vs keep.

### Standing Rule: Fix the Invariant, Not the Repro (FN-5893)

- When fixing a bug, the regression test must assert the general invariant across ALL known surfaces — not only the single reported reproduction.
- Symptom-based acceptance is mandatory for bug-class tasks: the final verification must reproduce the original failure condition and assert it no longer occurs via a real automated test. Encode this as a `## Symptom Verification` section in PROMPT.md with **Original symptom**, **Exact reproduction**, and **Assertion it is gone**; green build/tests alone are insufficient. This marker is the contract consumed by the GitHub auto-close gate (FN-6230).
- Surface enumeration is now an enforced bug-fix artifact: the spec must include a `## Surface Enumeration` section, planning must REVISE when that section is missing, and review must REVISE any repro-only regression test.
- The Surface Enumeration gate also applies to tasks that add or remove UI affordances (icons, buttons, chevrons, toggles, badges, menu entries, click targets), including Review Level 0 cosmetic tasks.
- Enumerate the surfaces before filing or closing the fix: every provider/bridge for streaming and agent paths, both desktop and mobile breakpoints for UI behavior, empty/undefined/duplicate/populated data states, and every shared hook/component/module/helper that reuses the affected logic.
- After removing a UI affordance, explicitly check for and clean up empty button shells, orphaned click targets, now-unused wrappers, and dangling aria-labels across both desktop and mobile breakpoints.
- Use the canonical checklist in `docs/testing.md` → **Surface Enumeration checklist** so planning and review enumerate the same surfaces.
- Motivating incidents: streamed-response spacing was fixed three times before the invariant was fully covered (FN-5787, FN-5789, FN-5803), the usage "Show hidden" button regressed three times before broader coverage stuck (FN-5797, FN-5875, FN-5919), and the auto-merge blank-dashboard fix re-opened after desktop-only coverage missed mobile Android (FN-5751).
- Motivating incident for UI affordances: the workflow-row drop-down arrow removal took three tasks (FN-6115 → FN-6118 → FN-6123) because the affordance rendered in two components and mobile kept an empty 36×36 `btn-icon` button shell.
- If a regression test only proves the exact reported case, it is incomplete; extend it until the invariant holds across all known surfaces.

### Port 4040 is Reserved

Never kill processes on port 4040 and never start test servers on 4040. Use `--port 0` or another free port.

### Never run an unbounded `find` against the system temp directory

Do not issue a recursive `find` (or any unbounded recursive directory walk) rooted at the OS temp directory — `$TMPDIR`, `/tmp`, or macOS `/var/folders/...` (canonical `/private/var/...`). The temp root can hold an enormous number of entries on CI and long-lived dev hosts, so a broad scan can hang for minutes and pin I/O.

When you need a Fusion temp artifact, target the known prefix directly and list a single level with a prefix filter — never walk the whole temp tree. The canonical bounded pattern is the engine's own sweep: non-recursive `readdirSync(...)` passes over the configured `<worktreesDir>/.ai-merge/` root plus legacy `.fusion/ai-merge/` and `tmpdir()` leftovers, filtered by a known prefix such as `fusion-ai-merge-` (`SelfHealingManager.cleanupStaleTempMergeWorktrees()` in `packages/engine/src/self-healing.ts`). Scoped `find` calls under a project worktree or `.fusion/` are fine; only the broad temp-root scan is forbidden.

### Engine Process Rules

#### Never use `execSync` for user-configured commands

Run user-configured commands (test/build/workflow scripts) via async `exec` with timeout. `execSync` is only acceptable for short deterministic git plumbing.

#### Move-Task contract

User `moveTask(in-progress → todo)` is a hard cancel: abort active sessions/subprocesses and park task in `todo` with user-paused semantics. Engine rebounds must not set `userPaused`.

#### Process supervision

Use `superviseSpawn(...)` from `@fusion/core` for managed child processes; do not use raw detached `spawn`/`nohup` patterns unless explicitly allowlisted. `eslint.config.mjs` + `scripts/check-no-nohup.mjs` enforce this.

### Git Conventions

- Commit prefixes: `feat(FN-XXX):`, `fix(FN-XXX):`, `test(FN-XXX):`
- One commit per step boundary
- Include task ID prefix
- Fusion task-worktree commits should carry `Fusion-Task-Id: FN-NNNN` trailers

### Merging Branches Into Main

1. **Drop duplicate commits before merging.** Rebase away duplicates already on main.
2. **Squash is now the project default; history-preserving merge paths require opt-in.** New projects default `directMergeCommitStrategy="always-squash"`. To preserve multi-commit history, explicitly set project `directMergeCommitStrategy` to `"auto"` or `"always-rebase"`, or set a per-task `**Direct Merge Commit Strategy:** ...` override in `PROMPT.md`.
3. **Empty cherry-picks are no-ops.** Do not create empty commits.
4. **Already-on-main classifier applies.** Allow finalize/self-healing recovery when lineage is landed.
5. **Contamination auto-recovery is bounded.** First pass can auto-drop upstream foreign commits; repeated/ambiguous cases escalate.
6. **Run post-squash audit policy.** Respect `postMergeAuditMode` (`warn`/`block`/`off`) and auto-recovery stages.
7. **Enforce pre-commit diff-volume gate.** Block suspicious shrinkage before squash commit.
8. **Smart-prefer-main overlap guard.** Recent overlapping main commits can flip to prefer-branch.
9. **Layer-3 scope partition.** Out-of-scope conflicts resolve to main before AI arbitration unless `task.scopeOverride=true`.
10. **Auto-prerebase on divergence/hot files.** Fail-soft and continue normal conflict stack.

### Gitignored-path guard on squash merges

Never force-add ignored artifacts (for example `git add -f .fusion/...`). Use task documents for findings/notes.

### File-Scope invariant on squash merges

Every squash commit must overlap task `## File Scope` (unless scope is empty). Violations must fail with `FileScopeViolationError` and reset pre-squash state.

Per-task opt-out exists: `task.scopeOverride = true` (log the reason).

### `autoMerge: false` callout (FN-5147)

When `settings.autoMerge: false`, `in-review` is terminal-until-merged by a human. Lifecycle-mutating self-healing must not move these tasks backward, pause/fail them, or re-enqueue them for execution.

Scoped exception (FN-5819): shared-branch-group members (`branchContext.assignmentMode === "shared"`) still run the member→shared-branch local integration step while auto-merge is off. This exception is only for assembling `branch_groups.branchName`; shared-branch → default-branch promotion remains gated by group/global auto-merge.

### Mock provider (test mode)

`testMode?: boolean` is now available in both project and global settings. If project `testMode === true` (or the resolved default provider is `"mock"` at any tier), every AI lane is forced to `mock/scripted`, overriding per-task and per-lane model selections. The dashboard exposes this via the Settings Modal "Enable test mode" toggle and a persistent "Test mode — no real AI calls" banner.

### Run Audit

- FN-5419: git run-audit now includes `pull:fast-forward` and `stash:pop-conflict`; dashboard git surfaces now include the extended `POST /api/git/pull` integration-worktree path plus companion `POST /api/git/stash-resolve`, `POST /api/git/stash-drop`, and `POST /api/git/stash-apply` routes.
- FN-6292: self-healing emits `task:reconcile-dependency-blocking-lease` when it rebounds an in-progress holder whose stale file-scope lease blocks an unmet dependency, and `task:reconcile-dependency-blocking-lease-no-action` when triple-proof blocks that backward move.


## Reference docs (deeper detail)

- `./docs/architecture.md` — lifecycle invariants, self-healing rules, reliability interaction backstops, run-audit internals.
- `./docs/testing.md` — full testing lanes, worker fanout guidance, test taxonomy, weekly velocity baseline, and file organization.
- `./docs/test-velocity-baseline.md` — weekly #leads-ready test feedback-loop velocity report generated by `scripts/test-velocity-baseline.mjs`.
- `./docs/dashboard-guide.md` — dashboard behavior and **Styling Guide** details. User-facing docs for Merge Advance Notice and Smart Pull live here.
- `./docs/PLUGIN_AUTHORING.md` — plugin authoring guide, lifecycle hooks, routes, tools, and dashboard-extension surfaces.
- `./docs/agents.md` — pi extension scope, coordination tools, checkout leasing, runtime config.
- `./docs/settings-reference.md` — model-selection hierarchy, mock provider mode, token budget precedence, presets.
- `./docs/storage.md` — hybrid storage model details, including per-task `agent-log.jsonl` storage and retention semantics.
- `./docs/multi-project.md` — central/per-project DB and isolation modes.
- `./docs/missions.md` — mission/milestone/slice/feature model.
- `./docs/workflow-steps.md` — prompt/script gates and merge-blocking behavior.
- `./docs/secrets.md` — secrets policy and tooling behavior.
- `./docs/diagnostics.md` — engine diagnostic logging conventions.
- `./docs/task-management.md` — archive cleanup and restore semantics.
- `./docs/soft-delete-verification-matrix.md` — mandatory soft-delete verification matrix.
- `./docs/cli-reference.md` — CLI and terminal UI reference.
- `./docs/contributing.md` — contributing conventions and release-adjacent context.
- `./docs/solutions/` — documented solutions to past problems (bugs, architecture patterns, best practices, conventions), organized by category with YAML frontmatter (`category`, `module`, `tags`, `problem_type`, `applies_when`). Relevant when implementing or debugging in documented areas.
- `./CONCEPTS.md` — shared domain vocabulary (entities, named processes, status concepts). Relevant when orienting to the codebase or discussing domain concepts.

### Lazy-Loaded Heavy Views

These 23 views are lazy-loaded via `React.lazy()` with `<Suspense fallback={null}>`.
Keep this AGENTS inventory in sync with App lazy imports, AppModals lazy modal imports (`SettingsModal`, `WorkflowNodeEditor`, `SetupWizardModal`), and `packages/dashboard/app/__tests__/lazy-loaded-views-docs.test.ts`.

- `AgentsView`
- `NodesView`
- `ChatView`
- `MemoryView`
- `DevServerView`
- `SecretsView`
- `InsightsView`
- `DocumentsView`
- `SkillsView`
- `ResearchView`
- `ReliabilityView`
- `CommandCenter`
- `EvalsView`
- `TodoView`
- `GoalsView`
- `StashRecoveryView`
- `PullRequestView`
- `SetupWizardModal`
- `SettingsModal`
- `WorkflowNodeEditor`
- `PluginManager`
- `PiExtensionsManager`
- `AgentDetailView`

## FNXC_LOG comments:
   - Please whenever you're working on a codebase. I want you to add comments describing the date of the change (must be in this format yyyy-MM-dd-hh:mm) and describing the requirements or the change in requirements that made you implement certain functionality.
   - I want you to write FNXC:Area-of-product in front of all your comments so they can be grepped.
   - Most of this should be written as jsdocs but you can add short comments around for the important variables and more complex parts of the codebase.
   - The idea is to encode the requiements of the system (especially software behavior, UX, and important technical decisions) into the code so it's clearer later why a certain piece of code was written.
   - Always make sure to keep these comments updated as you work in the codebase and requirements change.
   - Use technical writing principles to write non-verbose comments that convey the important info without fluff.
   - Keep in mind that ALL of the important user facing requirements sent by the user must be written as comments somewhere in the codebase.
   - There's no need to add line breaks in FNXC comments to stay under a certain character width. Just add line breaks normally at the ened of sentences.

   Good Example for a FNXC Comment:
   ```
   /*
   FNXC:SettingsNavigation 2026-05-13-08:05:
   The Settings dialog needs enough horizontal room for a main-tab section sidebar while Ghostty settings live in their own second tab.
   Use scoped CSS so the native modal host and Storybook share the same width without relying on newly generated utilities.

   FNXC:SettingsNavigation 2026-05-13-08:11:
   The modal should be 20% wider than the first section-sidebar layout and use a taller viewport so more settings remain visible without scrolling.
   */
   ```