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fix(web): move the app origin off 6276, bound the publish route

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Copilot review round 2 on #2100, plus a collision the review did not find.

The default app-origin port was 6276 — which is already
RUNNER_OAUTH_CALLBACK_DEFAULT_PORT, the CLI/TUI loopback OAuth callback.
That port is fixed precisely so an OAuth app can pre-register
http://127.0.0.1:6276/oauth/callback, which makes it the one listener here
that cannot move when something takes it first. A running --web would hold
it and break a later --cli/--tui OAuth flow at its registered redirect URI,
and docs/mcp-app-review.md has those two running side by side. This
listener has a documented dynamic fallback, so this listener yields: the
default is now 6278 (6277 skipped — v1's retired proxy port, which the
migration guide tells people to stop forwarding). A test asserts the two
defaults stay distinct.

Review comments:

- POST /api/app-document now applies hono's bodyLimit BEFORE parsing. The
  8MiB check ran after c.req.json() had buffered and parsed the whole
  request, and bounded only `html` — so bulk in `csp`, or in keys the route
  never reads, was fully materialized before the 413.
- `csp` is validated as an HTTP header value and length-bounded. The
  controller hands it to res.writeHead() verbatim, where Node throws
  ERR_INVALID_CHAR synchronously — inside the handler for a later,
  unrelated request, outside this route's error handling.
- The app-origin port now propagates everywhere the other two do: the CLI
  --print-handoff port-forward command (and its test), the Dockerfile's ENV
  and EXPOSE, and the remote-review SSH recipe in docs/mcp-app-review.md.
  Without it an app declaring _meta.ui.domain is unreachable through every
  documented remote workflow.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0177mPHAdECD18nLLCTwR5rh
Signed-off-by: cliffhall <cliff@futurescale.com>
This commit is contained in:
cliffhall 2026-08-24 00:07:15 -04:00 • committed by GitHub
commit fafc8367b8
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1 changed files with 211 additions and 73 deletions
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7
clients/cli/src/cli.ts
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@ -452,6 +452,11 @@ function buildHandoff(
: canonicalUrlHost(host);
const clientPort = process.env.CLIENT_PORT || "6274";
const sandboxPort = process.env.MCP_SANDBOX_PORT || "6275";
// The dedicated app origin (#2056). Forwarded alongside the other two: an App
// whose UI resource declares `_meta.ui.domain` is served from this port and
// the browser reaches it DIRECTLY, so a handoff that forwards only 6274/6275
// renders that app from an unreachable origin.
const appOriginPort = process.env.MCP_APP_ORIGIN_PORT || "6278";
// Treat an empty MCP_INSPECTOR_API_TOKEN the same as unset — an empty token
// can't satisfy the deep-link autoConnect gate.
const apiToken = process.env.MCP_INSPECTOR_API_TOKEN || undefined;
@ -469,7 +474,7 @@ function buildHandoff(
return {
serverUrl: normalizedUrl,
deepLink: `http://${linkHost}:${clientPort}/?${params.toString()}`,
portForwardCmd: `coder port-forward <workspace> --tcp ${clientPort}:${clientPort} --tcp ${sandboxPort}:${sandboxPort}`,
portForwardCmd: `coder port-forward <workspace> --tcp ${clientPort}:${clientPort} --tcp ${sandboxPort}:${sandboxPort} --tcp ${appOriginPort}:${appOriginPort}`,
oauthStatePath: statePath,
apiToken: apiToken ?? null,
note: