ClientIdMiddleware was running the SQLAlchemy SELECT/INSERT/UPDATE/COMMIT
inline on the event loop after every /mcp/* and /speak request. SQLite
serialises writes, so concurrent MCP traffic queued behind the stamp
write — the response sat waiting on a side-effect that the client never
needs in band, and SSE streams would stall briefly per request.
The middleware now hands the stamp to asyncio.to_thread via a fire-and-
forget create_task so the response returns immediately and the write
runs on the default executor. A module-level set keeps strong refs to
in-flight tasks (per asyncio docs) so the GC can't collect them mid-
write. The fallback path runs the stamp inline if no loop is available
(tests/oddball callers) rather than silently dropping it.
audio_path mode took any absolute filesystem path and returned its
decoded contents as transcribed text with no caller verification beyond
the existence/size checks. The X-Voicebox-Client-Id middleware records
the header but never rejects an absent or fake one, so a Voicebox bound
to 0.0.0.0 (the documented "remote access" mode) was effectively an
unauthenticated arbitrary-local-file read primitive.
The middleware now stashes the request's remote address in a ContextVar
alongside the existing client_id, and audio_path mode refuses anything
that doesn't parse as a loopback address (IPv4 127.0.0.0/8, IPv6 ::1).
audio_base64 mode is unchanged — that path was always bounded to bytes
the caller already has.
Loopback callers (the Tauri webview, local CLI scripts, MCP clients on
the same machine) keep working. Remote callers now have to send the
audio over the wire if they want it transcribed.
POST /speak is a REST wrapper around voicebox.speak for agents that
don't talk MCP (shell scripts, ACP, A2A). It reads X-Voicebox-Client-Id
and uses it for the same per-client profile resolution + default
personality lookup the MCP tool does (speak.py:39-64), so its callers
are first-class clients — but the ClientIdMiddleware only stamped
last_seen_at on /mcp* paths. REST speak callers showed up as "never
seen" in Settings → MCP despite actively acting on their bindings.
Widen the stamp predicate to an explicit ("/mcp", "/speak") prefix
list, and require a path boundary on match so future routes named
/mcpfoo or /speakers don't silently inherit the stamp via the prefix.
New test_client_id_middleware.py pins the scope with 17 parametrised
cases (both the allowed set and the overlap cases that must not match).
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
Jamie Pine