callstack__agent-device/AGENTS.md

AGENTS.md

agent-device is a CLI and daemon for automating Apple, Android, HarmonyOS, Vega, Linux, and web targets. A long-lived daemon owns sessions; registry-derived commands route to platform runtimes.

Task routing

Load only the procedures relevant to the task:

When the task involves	Read
Domain vocabulary	CONTEXT.md, docs/agents/domain.md
Architecture decisions	docs/adr/README.md
Tests or gate selection	docs/agents/testing.md
Selector capture, polling, or interaction fast paths	docs/agents/selector-capture.md
Adding or changing a CLI flag	docs/agents/cli-flags.md
Opening or reviewing a PR	docs/agents/pull-requests.md
Apple runner changes or manual device verification	docs/agents/device-verification.md
Writing issues or PRDs, and triage labels	docs/agents/issue-tracker.md, docs/agents/triage-labels.md
Web backend setup or diagnostics	docs/agents/web-backend.md

Versioned CLI help owns command semantics. Read the relevant topic when behavior is unclear; normal app-driving startup follows the skill's routing card.

Incident-derived principles

• Classify interaction dispatch paths in packages/contracts/src/interaction-guarantees.ts and verify each claim against the native implementation.
• Delegation on error proves no success-path parity. A fast path may succeed on a candidate the shared rules would refuse.
• Prove both paths are reachable before measuring a fast path against its baseline.
• Repair recurring failures at the owning type, registry, or construction path; do not add guards that reconstruct another source of truth.
• Keep control-flow narration and review history out of implementation comments. Encode invariants in names, types, boundaries, and tests; reserve comments for public API docs, tool directives, and non-obvious constraints that cannot be encoded.
• Key behavior on typed reasons and details, never error text; do not copy existing message sniffs.
• Keep metadata at response level when it applies to the whole snapshot. Append warnings through the shared response builder; never replace prior warnings.
• Before preserving a compatibility shape, run git tag --contains <commit>. Unreleased API has no external compatibility obligation.

Declaration sites and enforcement

Read the declaration rather than maintaining a prose copy:

• commands and their surface, runtime-use, batch, and timeout traits: packages/command-registry/src/registry.ts
• daemon route ownership and request-policy traits: src/daemon/daemon-command-registry.ts
• interaction paths and guarantees: packages/contracts/src/interaction-guarantees.ts
• canonical command names: packages/command-registry/src/catalog.ts
• device runtime-use declarations and fact admission: packages/command-registry/src/registry.ts, src/daemon/runtime-admission.ts, and src/platform-runtime-gateway.ts
• common command input fields, and which surface may write an input key (model, operator, retired): src/commands/common-input-fields.ts and src/commands/input-audience.ts

Shared selector parsing and matching belongs in @agent-device/selectors; request cancellation and progress in @agent-device/capture-kit (request-cancel, request-progress); cross-layer contracts in @agent-device/contracts; CLI flags in src/commands/cli-grammar; cross-surface schema composition in src/cli-schema.

Resolve registry completeness failures at the missing declaration. Diagnose other gate failures at their reported invariant; do not suppress them or add an allowlist to get a pass. Build interaction responses through buildInteractionResponseData; change cross-language rules through golden tables under contracts/fixtures/.

Hard repository rules

• Plain .mjs packaging fixtures that cannot import TypeScript execution helpers keep child-process use local and prefer execFile.
• Apple target changes keep the kernel device model, runtime-fact admission, dispatch resolution, Apple discovery, and xctestrun preparation in sync.
• iOS simulator-set scoping must never hide the host macOS desktop target.
• Skills stay minimal routing cards.
• Add compatibility or fallback behavior only when explicitly requested or approved. Otherwise, complete the migration and remove superseded paths.
• Keep changes within one command family or module group unless the task explicitly crosses a boundary. Platform-neutral work does not license inspecting every platform implementation.

Module and test topology

• Name modules for the domain question they answer and colocate machine-readable claims with their enforcement. Internal barrels are legacy; add barrels only at package boundaries.
• Implementation files target at most 300 lines. Extract before adding behavior past 500 lines; files past 1,000 lines are architecture debt unless generated or fixture data.
• Tests mirror source topology one-to-one. Split a source module and its test together; do not add to the legacy interaction.test.ts or platform index.test.ts aggregations. Pure moves carry their tests unchanged; rename-only hunks owe no new coverage.
• src/daemon/handlers/session.ts is already over budget; extract the relevant platform-specific concept before adding behavior.

Toolchain and worktree traps

• Use pnpm; never add package-lock.json. OXC owns lint and format. Run pnpm format repository-wide, not path-scoped.
• A fresh worktree requires pnpm install --frozen-lockfile && pnpm build. Until then package and optional-peer resolution may point at another checkout and produce false failures.
• Parallel work needs disjoint edit ownership and distinct devices. Run one full gate per host; concurrent subprocess-backed suites can produce contention timeouts.
• The layering scan reads tracked files only. Stage a new module before trusting its result.
• Fallow baselines are path-keyed. Move the matching baseline entry when renaming a file; never bulk regenerate baselines to accept unrelated findings.

Runtime and diagnostics seams

Diagnostics use @agent-device/capture-kit/diagnostics. Request diagnostics belong in the session request log; session artifact paths come from src/daemon/session-artifact-paths.ts. App/device logs remain in app.log; Apple runner and xcodebuild output remains in runner.log.

Normalize failures with normalizeError and preserve hint, diagnosticId, logPath, and typed details. An interaction taking five seconds or more is a daemon-log question: inspect runner restart, stale-session recovery, accessibility failure, transport retry, and timeout evidence.

Optional probes and caches are best-effort only when the feature contract says so. Their budgets must be shorter than the required operation they precede.

Selector and replay invariants

Element interactions support selector and @ref, then record a selector chain after resolution. Replay failures may re-resolve that chain only to produce a ranked divergence suggestion; ADR 0012 retired silent script rewriting.

Selector keys stay centralized in @agent-device/selectors; is predicates use evaluateIsPredicate. On macOS, snapshot rectangles are absolute in window space and point actions translate through the interaction root frame. Prefer selector or ref tests over raw coordinates.

Documentation ownership

Keep this file to repository traps and routing. Put task procedures in docs/agents/, decisions in ADRs, and command semantics in versioned help. Link to executable registries instead of duplicating their rules. CONTEXT.md is glossary-only: no implementation paths, decisions, or migration status.

Behavior changes update owning help/metadata and user docs. Report docs or skill changes when relevant.