ci: stop installing the mcap CLI in CI

.github/workflows/ci.yml

@@ -22,8 +22,6 @@ jobs:
 
   e2e:
     runs-on: ubuntu-latest
-    env:
-      MCAP_CLI_VERSION: 'v0.2.0'
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
@@ -32,18 +30,12 @@ jobs:
           cache: 'npm'
       - run: npm ci
       - run: npx playwright install chromium --with-deps
-      - name: Install mcap CLI
-        # Used by scripts/gen-test-mcap-filtered.mjs to derive a fixture via
-        # the real `mcap filter` command (not @mcap/core). That script
-        # self-skips if this step is ever removed, so it's not load-bearing
-        # for the rest of CI, but keeping it here exercises the multi-source
-        # merge feature's "mcap filter"-derived fixture on every run.
-        run: |
-          curl -sSL -o /usr/local/bin/mcap \
-            "https://github.com/foxglove/mcap/releases/download/releases/mcap-cli/${MCAP_CLI_VERSION}/mcap-linux-amd64"
-          chmod +x /usr/local/bin/mcap
-          mcap --version
       - name: Generate E2E fixtures
+        # The `mcap` CLI is a local-only debugging tool (not installed in
+        # CI): scripts/gen-test-mcap-filtered.mjs detects its absence and
+        # self-skips (no test_multi_filtered.mcap), and the Playwright spec
+        # that depends on that fixture skips itself in turn. Everything else
+        # still runs.
         run: npm run gen:e2e:fixtures
       - run: npm run test:e2e
         env:

docs/DEVELOPMENT.md

@@ -40,7 +40,7 @@ Vitest layout round-trip tests import JSON directly from `test-fixtures/layouts/
 
 Two fixtures depend on a tool that isn't an npm package. Their generator scripts detect absence and skip (exit 0, no output file) rather than failing the whole `gen:e2e:fixtures` run; Playwright specs that need one of these files check for it and `test.skip()` themselves when it's missing.
 
-- **`mcap` CLI** (Rust rewrite, `mcap --version` ≥ 0.1) — needed only to (re)generate `test_multi_filtered.mcap` via `mcap filter`. Install with `brew install mcap` or download a binary from <https://github.com/foxglove/mcap/releases?q=mcap-cli>. CI installs it explicitly (see `.github/workflows/ci.yml`), so this fixture and its tests always run there.
+- **`mcap` CLI** (Rust rewrite, `mcap --version` ≥ 0.1) — a local-only debugging tool, needed only to (re)generate `test_multi_filtered.mcap` via `mcap filter`. Install with `brew install mcap` or download a binary from <https://github.com/foxglove/mcap/releases?q=mcap-cli>. **CI does not install it**: `test_multi_filtered.mcap` and the one Playwright spec that depends on it simply skip there; everything else runs normally.
 - **`rosbags`** Python package — needed only to *regenerate* the committed `test-fixtures/media/minimal-multi.bag` source (e.g. after changing its schema in `scripts/gen-test-bag.py`); `npm run gen:e2e:fixtures` just copies that committed file into `public/examples/test_multi.bag`, so CI and most contributors never need to install it. If you do: `pip install rosbags`.
 
 For sample deep links (`?url=sample://…`), set `VITE_SAMPLE_DATASETS_MANIFEST_URL` in `.env` to a reachable JSON manifest (see `src/services/sampleDatasets.ts`).

scripts/gen-e2e-fixtures.mjs

@@ -33,13 +33,16 @@ runNode('gen-test-mcap-compressed-depth.mjs');
 runPython('gen-test-hdf5.py');
 runNode('gen-test-bvh.mjs');
 
-// Multi-source merge fixtures. gen-test-mcap-filtered.mjs and gen-test-bag.py
-// each self-skip (exit 0) when their optional external tool (`mcap` CLI /
-// `rosbags` package) isn't installed, so this pipeline still succeeds for
-// contributors without them; CI installs both (see .github/workflows/ci.yml).
+// Multi-source merge fixtures.
 runNode('gen-test-mcap-multi-base.mjs');
 runNode('gen-test-mcap-multi-incremental.mjs');
+// Uses the local-only `mcap` CLI; self-skips (exit 0, no output file) when
+// it isn't on PATH, which is always the case in CI by design (see
+// .github/workflows/ci.yml) — the Playwright spec that depends on this
+// fixture skips itself in turn.
 runNode('gen-test-mcap-filtered.mjs');
+// Copies the committed test-fixtures/media/minimal-multi.bag; only needs
+// the `rosbags` Python package to *regenerate* that committed source.
 runPython('gen-test-bag.py');
 
 console.log('[gen-e2e-fixtures] all fixtures ready');

scripts/gen-test-mcap-filtered.mjs

@@ -5,11 +5,11 @@
  * multi-source-merge test plan's requirement to exercise `mcap filter` for
  * fixture generation.
  *
- * Requires gen-test-mcap-multi-base.mjs to have run first. Skips gracefully
- * (exit 0, no output file) when the `mcap` CLI isn't on PATH, so contributors
- * without it installed still get every other fixture; tests that depend on
- * this file self-skip when it's absent. CI installs the CLI so it always
- * runs there (see .github/workflows/ci.yml).
+ * The `mcap` CLI is a local-only debugging tool and is intentionally *not*
+ * installed in CI. Requires gen-test-mcap-multi-base.mjs to have run first.
+ * Skips gracefully (exit 0, no output file) when the `mcap` CLI isn't on
+ * PATH, so contributors (and CI) without it installed still get every other
+ * fixture; tests that depend on this file self-skip when it's absent.
  */
 import { spawnSync } from 'node:child_process';
 import fs from 'node:fs';