Tomtom Maps Sdk JS Contribution

You are working as an SDK contributor on the TomTom Maps SDK for JavaScript monorepo.

AGENTS.md files are the cross-tool source of truth for contributor guidance in this repo (architecture, commands, conventions, workflows). This skill orients you to them — do not restate or duplicate their content here.

Orientation steps

1. Always read the root AGENTS.md first for architecture, build order, dev commands, conventions, and key files.

2. Read the package-specific AGENTS.md for the area you're touching:

   If the task touches…	Read
   core/	core/AGENTS.md
   map/	map/AGENTS.md
   services/	services/AGENTS.md
   examples/	examples/AGENTS.md (and examples/E2E_TESTING.md for test work)
   map-integration-tests/	map-integration-tests/AGENTS.md
   plugins/ (any)	plugins/AGENTS.md
   plugins/agent-toolkit/	plugins/agent-toolkit/AGENTS.md + plugins/agent-toolkit/ENGINEERING-GUIDELINES.md
   plugins/viewport-places/	plugins/AGENTS.md (no dedicated AGENTS.md; see src/viewportPlaces.ts)
   plugins/landmarks-3d/	plugins/AGENTS.md (no dedicated AGENTS.md; see src/Landmarks3D.ts)
   shared-configs/	shared-configs/AGENTS.md
   documentation/	documentation/AGENTS.md
   documentation/docs-portal/	documentation/docs-portal/AGENTS.md (guide writing with SDKGuideLiveCodingExample)

   If the area is unclear, read all package-level AGENTS.md files before acting.

3. Before you write code, silently confirm you're in contributor mode with these easy-to-violate rules top-of-mind:

   • Biome for formatting/linting (not ESLint or Prettier). Run pnpm lint from root.
   • pnpm for package management; shared version pins live in pnpm-workspace.yaml under catalog:.
   • Vitest for unit tests; place tests in tests/ subdirectories next to source.
   • Strict TypeScript — no any, no unnecessary casts.
   • Coordinates: always [longitude, latitude] (GeoJSON order) — easy to get wrong.
   • Full variable names — response not res, parameters not params, error not err, configuration not config, etc. (full list in root AGENTS.md).
   • Arrow functions over function declarations; omit braces/return for single-expression one-liners.
   • No re-exports — import directly from canonical source, never barrel-forward.
   • Blank line after single-line if — Biome does not enforce; apply manually.
   • Map modules: get instances via await SomeModule.get(map), never new SomeModule().
   • Tool execute in plugins must catch and return { error: string }, never throw.
   • Build order is strict: core → services + map. Never import map from services or vice versa.
   • Example E2E tests need dist/: every pnpm test:e2e[:update-snapshots] (per-example or via pnpm e2e-test:examples:update-snapshot <name> / pnpm generate-thumbnails:examples <name> from root) requires pnpm -F map build + pnpm -F @examples/<name> build first — the Playwright server serves dist/, not the dev server. Skipping the build silently uses stale assets.
   • New examples must ship both e2e-tests/snapshots/upon-load.png (from pnpm test:e2e:update-snapshots) and content/thumbnail.png (derived via pnpm generate-thumbnails:examples <name>). Commit both.

After every change

Always run both of these from the repo root after editing any source file, before reporting the task as complete:

pnpm lint:fix
pnpm format:fix

lint:fix runs Biome's check+lint with --write; format:fix runs Biome's formatter with --write. If lint:fix exits non-zero, fix the reported errors (warnings about pre-existing complexity/non-null-assertions in unrelated files are not blocking — only address what your change introduced or what Biome flags as an error).

Cross-file consistency check (before pushing)

Most automated review nags come from references that drift between code, exports, tests, and docs. Before pushing, do a quick sweep matched to the kind of change you just made.

Renamed or removed a public symbol — start with git grep -l '<oldName>' from the repo root, then walk the hits across:

• the package's own src/** (registries, barrels, schemas, tests, mocks, fixtures)
• examples/** (entry points, hooks, eval cases, tests, snapshots)
• documentation/docs-portal/guides/** — both navigation.yml and every .mdx under the affected guide
• .claude/skills/** — skill descriptions list trigger keywords by symbol name and go stale silently

Replace every hit. If the rename also changed semantics (not just the name), re-read the touched code so descriptions, JSDoc, and guides still match the actual runtime behavior — they go stale silently.

Changed a public type shape (default generic, exported interface, output schema) — also:

• update the JSDoc @typeParam / property docs to match the actual default and shape (a common review nag is "JSDoc says X but signature says Y")
• decide whether downstream consumers need a deprecated alias or a major-version bump (see .release-please-manifest.json)

Added external-resource fetching — confirm bounded handling: explicit protocol allowlist, AbortController timeout, streamed size cap. Don't trust new URL alone.

Package-specific extras — when a package's own AGENTS.md lists "after adding X, also touch Y" rules (e.g. plugins/agent-toolkit/AGENTS.md for new state slices or registered tools), follow those as well. The root-level checks above don't replace them.

When to branch off this skill

• Building an SDK consumer app (not editing SDK source) → use the tomtom-maps-sdk-js skill instead.
• Writing or editing customer-facing guides → follow documentation/docs-portal/AGENTS.md.
• Working on the agent-toolkit plugin → ENGINEERING-GUIDELINES.md is required reading before touching tools, state, or system prompts.