callstack__agent-device/AGENTS.md

AGENTS.md

Minimal operating guide for AI coding agents in this repo.

First 60 Seconds

• Classify task type:
  • Info-only (triage/review/questions/docs guidance): no code edits and no test runs unless explicitly requested.
  • Code change: make minimal scoped edits and run only required checks from Testing Matrix.
• State assumptions explicitly. If uncertain, ask.
• If the task touches tooling/builds/linting, read package.json and tsconfig*.json before source files.
• Prefer repo scripts over reconstructing command bundles by hand:
  • pnpm check:quick: lint + typecheck
  • pnpm check:tooling: lint + typecheck + build
  • pnpm check:unit: unit + smoke
  • pnpm check: full non-integration validation
• Read at most 3 files first:
  • owning handler/module
  • one shared helper used by that handler
  • one downstream platform file if needed
• Define verifiable success criteria before editing.
• Decide docs/skills impact up front.

Scope

• Solve issues with the smallest context read.
• Keep changes scoped to one command family or module group.
• Preserve daemon session semantics and platform behavior.
• Expand only when contracts cross module boundaries.
• Do not read both iOS and Android paths unless explicitly cross-platform.
• If requested fix expands beyond one command family/module group, stop and confirm before broadening scope.

Code Changes

• Minimum code that solves the problem. No speculative features.
• No abstractions for single-use code.
• Surgical edits only.
• Match existing style.
• Remove imports/variables YOUR changes made unused; do not clean unrelated dead code.
• Keep modules small for agent context safety:
  • target <= 300 LOC per implementation file when practical.
  • if a file grows past 500 LOC, plan/extract focused submodules before adding new behavior.
  • exception: generated files, schema/fixture snapshots, and integration test aggregations.

Routing

• Keep src/daemon.ts as a thin router.
• Put command logic in handler modules:
  • session/apps/appstate/open/close/replay/logs: src/daemon/handlers/session.ts
  • click/fill/get/is: src/daemon/handlers/interaction.ts
  • snapshot/wait/alert/settings: src/daemon/handlers/snapshot.ts
  • find: src/daemon/handlers/find.ts
  • record/trace: src/daemon/handlers/record-trace.ts
• Generic passthrough (press/scroll/type) is daemon fallback only after handlers return null.

Toolchain Snapshot

• Package manager: pnpm only. Do not add or restore package-lock.json.
• Lint/format stack is OXC:
  • config: .oxlintrc.json, .oxfmtrc.json
• TypeScript is strict enough to surface dead code early: strict, isolatedModules, noUnusedLocals, and noUnusedParameters are enabled.
• The repo emits with rslib, not tsc. If declaration generation fails, inspect tsconfig.lib.json first.
• tsconfig.lib.json needs an explicit rootDir: "./src" for declaration layout.
• Use the aggregate scripts in package.json when possible; they encode the expected validation bundles better than ad hoc command lists.

Cheap Exploration

• Prefer these first-pass commands over broader reads:
  • rg -n "<symbol|command|flag>" src test
  • rg --files src/daemon/handlers src/platforms/ios src/platforms/android
  • git diff -- <path> for active-branch context
  • read .oxlintrc.json before treating lint output as source-level bugs
• If build/type errors mention declaration generation, inspect tsconfig.lib.json before reading platform code.
• If lint failures appear after toolchain edits, check whether the rule is from eslint/*, typescript/*, import/*, or node/* in .oxlintrc.json before assuming source bugs.

Command Family Lookup

• logs: src/daemon/handlers/session.ts -> src/daemon/app-log.ts -> src/daemon/handlers/__tests__/session.test.ts
• open/close/replay/apps/appstate: src/daemon/handlers/session.ts -> src/daemon/session-store.ts -> src/daemon/handlers/__tests__/session.test.ts
• click/fill/get/is: src/daemon/handlers/interaction.ts -> src/daemon/selectors.ts -> src/daemon/handlers/__tests__/interaction.test.ts
• snapshot/wait/settings/alert: src/daemon/handlers/snapshot.ts -> src/daemon/snapshot-processing.ts -> src/daemon/handlers/__tests__/snapshot-handler.test.ts
• record/trace: src/daemon/handlers/record-trace.ts -> src/platforms/ios/runner-client.ts -> src/daemon/handlers/__tests__/record-trace.test.ts

iOS Runner Seams

• Keep dependency direction clean:
  • runner-client.ts: command execution + retry behavior
  • runner-transport.ts: connection/probing/HTTP transport
  • runner-contract.ts: shared RunnerCommand type and runner connect/error helpers
  • runner-session.ts: session lifecycle and request/response execution
  • runner-xctestrun.ts: xctestrun preparation/build/cache logic
• runner-transport.ts must not import back from runner-client.ts.
• If changing runner connect errors, retry policy, or command typing, start in src/platforms/ios/runner-contract.ts before touching client/transport files.

Hard Rules

• Use runCmd/runCmdSync from src/utils/exec.ts for process execution.
• Use daemon session flow for interactions (open before interactions, close after).
• Do not remove shared snapshot/session model behavior without full migration.
• Command/device support must come from src/core/capabilities.ts.
• Apple-family target changes must keep src/utils/device.ts, src/core/capabilities.ts, src/core/dispatch-resolve.ts, src/platforms/ios/devices.ts, and src/platforms/ios/runner-xctestrun.ts in sync.
• iOS simulator-set scoping is iOS-specific: do not let iosSimulatorDeviceSet hide the host macOS desktop target when --platform macos or --target desktop is requested.
• If Swift runner code changes, run pnpm build:xcuitest.
• Use inferFillText and uniqueStrings from src/daemon/action-utils.ts.
• Use evaluateIsPredicate from src/daemon/is-predicates.ts for assertion logic.

Logs Contract

• Logs backend/source of truth is src/daemon/app-log.ts.
• session.ts should orchestrate only (start/stop/path/doctor/mark), not duplicate backend logic.
• Preserve external grep/tail workflow in docs/skills.

Diagnostics & Errors

• Diagnostics source of truth: src/utils/diagnostics.ts
  • withDiagnosticsScope, emitDiagnostic, withDiagnosticTimer, flushDiagnosticsToSessionFile
• Do not add ad-hoc stderr/file logging where diagnostics helpers apply.
• Normalize user-facing failures via src/utils/errors.ts (normalizeError).
• Failure payload contract: code, message, hint, diagnosticId, logPath, details.
• Preserve hint, diagnosticId, logPath when wrapping/rethrowing errors.
• --debug is canonical; --verbose is backward-compatible alias.
• Keep redaction centralized in diagnostics helpers.

Selector System Rules

• Interaction commands (click, fill, get, is) and wait accept selectors and @ref.
• Pipeline: parse -> resolve -> act -> record selectorChain -> heal on replay.
• Keep selector parsing/matching in src/daemon/selectors.ts.
• Call buildSelectorChainForNode after resolving target nodes.
• New element-targeting interactions must support selector + @ref, record selectorChain, and hook replay healing (healReplayAction in session.ts + selector helpers in session-replay-heal.ts).
• New selector keys remain centralized in selectors.ts.
• New is predicates belong in evaluateIsPredicate.
• On macOS, snapshot rects are absolute in window space. Point-based runner interactions must translate through the interaction root frame; do not assume app-origin (0,0) coordinates.
• Prefer selector or @ref interactions over raw x/y commands in tests and docs, especially on macOS where window position can vary across runs.

Testing Matrix

• Docs/skills only: no tests required.
• Non-TS, no behavior impact: no tests unless requested.
• Any TS change: pnpm typecheck or pnpm check:quick.
• Tooling/config change (package.json, tsconfig*.json, .oxlintrc.json, .oxfmtrc.json): pnpm check:tooling.
• Daemon handler/shared module change: pnpm check:unit.
• iOS runner/Swift change: pnpm build:xcuitest.
• Cross-platform behavior change: run pnpm test:integration.
• Any change in: src/, test/, skills/: pnpm format.

Token Guardrails

• Do not read unrelated files once owning module is identified.
• Do not run integration tests by default.
• Do not inspect both iOS and Android codepaths unless task requires both.
• Prefer targeted git diff -- <paths> over broad file reads during review.
• Prefer snapshot -i, find, and scoped selectors over repeated full snapshot dumps when exploring Apple desktop UIs.
• Keep PR summaries short and scoped.

Common Mistakes

• Adding command logic to src/daemon.ts instead of handlers.
• Adding capability checks outside src/core/capabilities.ts.
• Inlining is predicate logic in handlers.
• Returning non-normalized user-facing errors.
• Duplicating logs backend logic in handlers instead of src/daemon/app-log.ts.
• Growing src/daemon/handlers/session.ts or src/platforms/ios/apps.ts further without extracting Apple-family/macOS-specific helpers first.
• Reintroducing an npm lockfile or assuming ESLint/Prettier still exist in this repo.
• Changing tsconfig.lib.json/build tooling without running pnpm check:tooling; declaration generation is stricter than tsc --noEmit.

Docs & Skills

• For behavior/CLI surface changes, evaluate docs/skills updates.
• Update README.md and relevant website/docs/** pages for command behavior/flags/aliases/workflows.
• Update relevant skills/**/SKILL.md when usage examples/workflow recommendations change.
• Keep skill docs task-first:
  • top-level SKILL.md should stay a thin router, not a full manual.
  • keep detailed workflows/troubleshooting in a references/ folder instead of growing the router.
  • isolate true platform/infra exceptions (for example macOS-only or remote-tenancy-only guidance) in dedicated files.
  • do not delete high-value operational guidance during refactors; move or condense it unless the behavior is obsolete.
• Optimize skills for cheap, less capable models:
  • keep routing explicit, shallow, and easy to follow in one pass.
  • prefer short task-first steps, concrete commands, and low-ambiguity wording over dense prose.
  • avoid long reference chains or “figure it out” guidance when a direct next action can be stated.
• In final summaries, state whether docs/skills were updated; if not, explain why.

When Blocked

• If blocked by network/device/auth/permissions, stop and report:
  • blocker
  • why it blocks completion
  • exact next command/action needed to unblock

Key Files

• CLI parse + formatting: src/bin.ts, src/cli.ts, src/utils/args.ts
• Daemon client transport: src/daemon-client.ts
• Daemon state/store: src/daemon/session-store.ts
• Selector DSL and matching: src/daemon/selectors.ts
• is predicate evaluation: src/daemon/is-predicates.ts
• Shared action helpers: src/daemon/action-utils.ts
• Snapshot shaping + labels: src/daemon/snapshot-processing.ts
• Handler context helpers: src/daemon/context.ts, src/daemon/device-ready.ts
• Dispatcher + capability map: src/core/dispatch.ts, src/core/capabilities.ts
• Platform backends: src/platforms/ios/*, ios-runner/*, src/platforms/android/*

Pull Requests

• Before opening PR: ensure no conflict markers/unmerged paths.
• Commit messages and PR titles should use conventional prefixes such as feat:, fix:, chore:, perf:, refactor:, docs:, test:, build:, or ci: as appropriate.
• Do not use bracketed automation prefixes such as [codex] or similar bot tags in commit messages or PR titles.
• Open a ready-for-review PR by default. Use a draft PR only when the user explicitly asks for one or the work is intentionally incomplete.
• Run required checks for touched scope from Testing Matrix.
• PR body must be short and include:
  • ## Summary
  • ## Validation with exact commands run
• Call out known gaps/follow-ups explicitly.
• Include touched-file count and note if scope expanded beyond initial command family.

Priority Order

• When guidance conflicts, apply in this order: Hard Rules -> Scope -> Testing Matrix -> style/preferences.