fusion/AGENTS.md

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• Do not cite .fusion/tasks/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.

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:

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:

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.

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: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: a non-recursive readdirSync(tmpdir()) 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.

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, and file organization.
• ./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 20 views are lazy-loaded via React.lazy() with <Suspense fallback={null}>. Keep this AGENTS inventory in sync with App lazy imports and packages/dashboard/app/__tests__/lazy-loaded-views-docs.test.ts.

• AgentsView
• NodesView
• ChatView
• MemoryView
• DevServerView
• SecretsView
• InsightsView
• DocumentsView
• SkillsView
• ResearchView
• ReliabilityView
• EvalsView
• TodoView
• GoalsView
• StashRecoveryView
• PullRequestView
• SetupWizardModal
• PluginManager
• PiExtensionsManager
• AgentDetailView