Which version line?

v2 — current (@modelcontextprotocol/inspector@latest)

Which client?

All / shared core

Inspector version

2.13.0 (v2/main @ d7f6cee, built from source)

Node version

v22.23.4

Operating system (and browser, for the web client)

Linux (Debian), Chrome for Testing 153 (headless, via Playwright)

Transport

stdio

MCP server under inspection

The repo's own stdio test server, default config:
node test-servers/build/test-server-stdio.js (built with npm run test-servers:build in clients/web).

Steps to reproduce

Each item lists its own repro; all on v2.13.0 built from source.

1. Web fonts from Google at runtime. Load the web UI with no internet access → console shows ERR_TUNNEL_CONNECTION_FAILED for fonts.googleapis.com (clients/web/index.html lines 7–9). With internet, every launch sends the user's IP to Google.
2. Sandbox listener (6275) robustness. curl -I http://127.0.0.1:6275/sandbox → 404; curl 'http://127.0.0.1:6275/sandbox?x=1' → 404; curl -H 'Host: rebind.evil.com' http://127.0.0.1:6275/sandbox → 200 (no Host allow-list, unlike the main server). sandbox-controller.ts matches req.url exactly.
3. SPA fallback prefix. curl http://127.0.0.1:6274/apixyz → 404; the fallback tests path.startsWith("/api") instead of "/api/" (clients/web/server/server.ts).
4. Ad-hoc server name differs by client. Same launch command: web names it node, TUI names it default.
5. Default seed on Windows. DEFAULT_SEED_CONFIG in core/mcp/serverList.ts seeds filesystem-server-default with /tmp, which does not exist on Windows.
6. No <h1> after connecting. axe-core page-has-heading-one on Tools/Prompts/Resources/Apps; the home screen passes.
7. List order differs. Tools are listed in server order in the TUI, alphabetically in the web client.
8. TUI nits. The tool form shows Test Tool: <name> twice; a comment near roots: cleanRoots(...) in clients/tui/src/App.tsx says the TUI has no roots editor, but one shipped in TUI has no UI for Tasks, resource subscriptions, or Roots #2432.
9. Weak custom token accepted silently. MCP_INSPECTOR_API_TOKEN=testtok is accepted with no warning.

Expected behavior

1. Fonts are bundled with the app; no third-party requests.
2. The sandbox answers HEAD and ignores a query string on /sandbox, and applies the same Host allow-list as the main server.
3. Non-API deep links get the SPA; only /api/ paths are excluded.
4. One naming rule for ad-hoc servers across clients.
5. The seed uses a platform temp dir (os.tmpdir()).
6. Every screen has an

   .

7. One list order in both clients (or a sort toggle in both).
8. A single title on the tool form; the comment reflects the roots editor.
9. A startup warning for a custom token shorter than 32 characters.

Actual behavior

See each numbered item in Steps to reproduce.

Logs, errors, or screenshots

axe-core scans were run with the copy shipped in clients/web/node_modules; all other axe rules passed on all five web tabs.

Already prototyped a fix?

No response

Before you submit

• I searched existing issues and this is not a duplicate.
• This is not a security vulnerability report (those go through the private advisory process).