Three findings, all from Copilot's suppressed block.
1. The tests never checked that loadBrowser launches the engine it was
asked for. The failure-path stand-in rejects identically for every
engine, so loadBrowser(root, "firefox") could have called
chromium.launch() and still produced a correctly Firefox-labelled
error. The smokes could not catch it either: the Firefox gate runs
after Chromium is already installed, so a mis-dispatched launch would
SUCCEED and report Firefox coverage that never happened.
Added a success-path test with distinct per-engine spies asserting the
requested engine is invoked, that nothing else is, and that its handle
is what comes back. Mutation-verified: hard-coding playwright.chromium
fails it.
2. The launch-failure message told the reader to run
`npx playwright install --with-deps <engine>`, which is wrong now that
the npm scripts run from the repo root rather than clients/web -- I
introduced that when I removed the `cd`. Playwright is pinned in
clients/web, so a bare root-level npx can fetch a different version and
install a browser revision the pinned one still cannot launch. It now
points at `npm run smoke:web:<engine>` first, and scopes the raw
command to clients/web with the reason.
That message named smoke:web:webkit, which did not exist -- only the
chromium and firefox scripts did. Added it, and a test asserting every
supported engine has one, since a remedy nobody can run is worse than
no remedy. Mutation-verified.
3. AGENTS.md said npm run ci "mirrors" the workflow and then, two
sentences later, that it is "a superset, not a mirror". It now leads
with strict superset, which is the topology this PR is documenting.
The README and AGENTS.md remediation wording is corrected the same way as
the runtime message, so a reader gets the same advice wherever they find
it.
Addresses Copilot review 5030668906 on #2133.
Signed-off-by: cliffhall <cliff@futurescale.com>
The job was trialled and did not earn its place. It was genuinely cheap —
~2 minutes, running in parallel with the 15-minute build job, so zero
added wall-clock — but across a dozen runs Firefox never once disagreed
with Chromium. It was paying runner time and carrying a real flake
surface (playwright install --with-deps runs apt-get update, which fails
whenever a third-party repo in the runner image breaks; that is what the
one red run was) to re-confirm a result already in hand.
Everything that made cross-engine checking possible stays: SMOKE_BROWSER,
the shared headless-browser helper, the installer, and the tests. So
"SMOKE_BROWSER=firefox npm run smoke:web:engine" is there for the moment
it is worth running — before touching the sandbox, the CSP builder or the
proxy page — without taxing every push to re-derive the same answer.
The workflow is now byte-identical to v2/main again; the publish jobs go
back to needing only build.
Docs say what is true rather than what was intended, and AGENTS.md
records the reasoning so the job is not re-added on the general argument
that cross-engine coverage is good — that argument was already accepted,
and the on-demand path is what serves it. Re-add it on evidence: a real
cross-engine regression a gate would have caught.
Also swept the now-stale "matrix" language out of the smokes and the
resolver, including the empty-SMOKE_BROWSER rationale, which no longer
leans on a matrix key that does not exist.
Signed-off-by: cliffhall <cliff@futurescale.com>
#2132 was closed without the investigation going anywhere, so every
'pending #2132' pointer in the tree was about to send a reader to a
closed issue whose own diagnosis had already been retracted.
The docs now say what is actually known, and nothing more: the two App
smokes fail under Playwright's WebKit for unidentified reasons; it does
not reproduce in real Safari; an isolated repro of the suspected
mechanism did not reproduce it under Playwright's WebKit either; and
chasing it further was judged not worth the effort. A reader hitting it
locally is told to treat it as unexplained rather than as a defect.
The matrix decision is unchanged and never depended on the cause — the
engine fails, so it is not gated.
No behavior change.
Signed-off-by: cliffhall <cliff@futurescale.com>
Two findings from Copilot's suppressed block.
1. resolveBrowserName treated a present-but-empty SMOKE_BROWSER as unset
and returned chromium. The test that covered it even documented WHY
that is dangerous — GitHub Actions renders an undefined matrix key as
"" rather than omitting the variable — and then asserted the unsafe
behavior. A misspelled matrix key would run chromium inside a job named
for another engine and report green: the same false-coverage outcome
the unrecognized-value branch exists to prevent, reached by a typo
instead of a bad value.
Only an absent variable now selects the default. Empty throws, naming
the likely cause and the actual remedy ('unset it', which is not the
same as setting it to nothing). The workflow always renders a real
value, so nothing in CI is affected.
2. install-smoke-browser.mjs had no tests. Its I/O half runs on every
smoke and fails loudly; its argument half does not — every caller
passes nothing or the literal 'chromium', so the precedence rule is
asserted by nothing at runtime. It matters: pack:verify passes chromium
BECAUSE it launches chromium, and if the environment won,
SMOKE_BROWSER=webkit npm run pack:verify would install one engine and
launch another, surfacing as a misleading "Executable doesn't exist".
resolveRequestedBrowser is now exported and pure; execution moved
behind main() with the entrypoint guard verify-typecheck-coverage.mjs
uses, so importing the module for tests cannot trigger an install.
Both mutation-verified: restoring either behavior fails the tests that
claim to cover it.
Addresses the suppressed comments on Copilot's fifth review of #2133.
Signed-off-by: cliffhall <cliff@futurescale.com>
Two findings from Copilot's suppressed block.
1. The launch-failure message is #2086's acceptance criterion — a missing
browser must name THAT engine and its own install command — and it had
no test. The smokes cannot supply one: install-smoke-browser fetches
the binary first, so a passing smoke says nothing about what a failing
one prints, and that message is the deliverable. loadBrowser now takes
an injectable loadPlaywright purely to open that seam.
The test asserts per engine that the message leads with that engine,
names --with-deps <that engine> and no other, and preserves the
underlying cause. Verified by mutation: hard-coding 'chromium' in the
message fails it. It also pins the two branches apart — an unresolvable
package must say
> @modelcontextprotocol/inspector@2.3.0 postinstall
> node scripts/install-clients.mjs
[install-clients] Installing dependencies for clients/web...
up to date, audited 583 packages in 614ms
198 packages are looking for funding
run `npm fund` for details
found 0 vulnerabilities
[install-clients] Installing dependencies for clients/cli...
up to date, audited 237 packages in 496ms
69 packages are looking for funding
run `npm fund` for details
found 0 vulnerabilities
[install-clients] Installing dependencies for clients/tui...
up to date, audited 314 packages in 518ms
102 packages are looking for funding
run `npm fund` for details
found 0 vulnerabilities
[install-clients] Installing dependencies for clients/launcher...
up to date, audited 160 packages in 449ms
50 packages are looking for funding
run `npm fund` for details
found 0 vulnerabilities
up to date, audited 281 packages in 3s
108 packages are looking for funding
run `npm fund` for details
found 0 vulnerabilities and must NOT say ,
which fetches binaries and cannot fix a missing package.
The unsupported-engine test now also asserts loadPlaywright was never
called, pinning the ORDER rather than only the message: validating
first is what makes the error name the real mistake.
2. prod-web-server.mjs's header still described the prefix this PR removed. Corrected, keeping why
deriving paths from import.meta.url is still right, and adding the
elicitation smoke to the list of callers it had also outgrown.
Addresses the suppressed comments on Copilot's review of #2133.
Signed-off-by: cliffhall <cliff@futurescale.com>
#2132 was filed asserting that a Safari user opening an MCP App gets a
permanently 'loading' widget. That was never tested. A manual check in
real Safari renders the App normally, so the claim is unsupported and is
removed from all six places it reached.
The failure under Playwright's WebKit is real and still keeps that engine
out of the CI matrix. What is not established is that any shipping
browser behaves this way — and Playwright ships its own WebKit build
whose networking stack is not Safari's, which is exactly the layer the
failure lives in.
headless-browser.mjs already carried the caveat that a green WebKit run
is not a Safari guarantee. The same sentence forbids the inverse
inference, which is the one that was made; it now says so explicitly, and
AGENTS.md carries the rule: reproduce in the real browser before claiming
user impact in one.
No behavior change.
Signed-off-by: cliffhall <cliff@futurescale.com>
Every browser-driven check in this repo launched Chromium and nothing else.
That is fine for most of the web client, whose behavior is React and Mantine.
It is not fine for the MCP Apps sandbox, which is built out of the primitives
that genuinely diverge between engines: a CSP <meta> injected as the first
<head> child of a srcdoc document, a nested sandboxed iframe, a
Permissions-Policy allow attribute, and postMessage origin discipline across
those two frames. Nothing else covers that surface — sandbox-csp.test.ts
asserts which policy STRING is built (environment-independent by
construction), and no Storybook story reaches the sandbox at all, since all
three App stories use a data: placeholder iframe and a mock bridge.
The engine is now a parameter:
SMOKE_BROWSER=webkit npm run smoke:web:app
SMOKE_BROWSER=firefox npm run smoke:web:engine # all three smokes
Unset means chromium, so `npm run ci` and `npm run smoke` are unchanged. An
unrecognized value is an error rather than a fallback — falling back would
report a green Chromium run under a job labelled "webkit", claiming coverage
that never ran — and a launch failure names the engine that failed and its own
`playwright install` invocation.
Selection, launching, and the fatal-vs-benign page-diagnostics split now live
in one shared scripts/lib/headless-browser.mjs. The three smokes had each
hand-rolled the diagnostics split and two had their own copy of loadChromium;
pack:verify goes through the same helper, pinned to Chromium explicitly since
it is a packaging check.
The npm scripts drop their `cd clients/web && npx playwright install chromium`
prefix for scripts/install-smoke-browser.mjs. The engine is a variable now, and
a ${VAR:-default} expansion does not expand under Windows' cmd.exe; npx is also
a .cmd shim there that a shell-free spawn cannot start, so this resolves the
Playwright CLI through resolveNodeBin — the #1939 problem solved the #1939 way.
CI gains a `Sandbox smokes (<engine>)` matrix job rather than matrixing `build`,
which also runs validate, the coverage gate, two verify gates and Storybook —
all engine-independent. Both publish jobs now need it.
WebKit is supported by the tooling but deliberately NOT in the CI matrix yet:
pointing the smokes at it immediately found #2132, a pre-existing Safari
incompatibility in the web client's SSE transport that strands the last message
on /api/mcp/events, so an MCP App never leaves "loading". That is a product bug
affecting real Safari users, with its own diagnosis and a verified fix, and it
is not a matrix change. Adding `webkit` here is a one-word diff once it lands.
An engine is either green in CI or absent from it; a continue-on-error job would
report coverage nobody is held to.
Signed-off-by: cliffhall <cliff@futurescale.com>
