Drives /projects/:name/mcp over the real Streamable HTTP transport with a
fake websearch upstream: tools/list must serve `websearch_fetch_content`
(every name matching the OpenAI function-name charset), calling that wire
name must reach the upstream as bare `fetch_content`, and a legacy client
echoing the canonical `websearch/fetch_content` must still route.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JaFvfHrQyUKCGv6o3N2Wir
The proxy namespaces tools as `server/tool` (and favourite-index presents
`favourite/<tool>` / `all/<server>/<tool>`). A `/` is not a valid character
in an OpenAI-style function name, so hosts that forward MCP tool names
verbatim as LLM function names depend on the model faithfully echoing an
illegal name. LibreChat did exactly that: deepseek-v4-flash intermittently
dropped the `websearch/` prefix, LibreChat's registry lookup failed, and it
reported "This tool's MCP server is temporarily unavailable" while nothing
was down — the calls never reached mcplocal at all (confirmed against the
AuditEvent table, 2026-08-25). Claude Code and the pi extension only dodge
this because they sanitize names client-side.
Fix at the HTTP boundary only: a WireNameCodec rewrites tools/list responses
to wire-safe names (`/` -> `_`, exact-match reverse map, deterministic
suffix on collision) and maps tools/call names back before routing. Wired
into both /mcp and /projects/:name/mcp. Everything inside the proxy —
routing maps, plugins, favourites config, audit events — keeps canonical
names, and unknown inbound names (legacy clients echoing slash names,
virtual tools) pass through unchanged, so existing clients keep working.
Codecs are keyed per project and outlive the router cache TTL so a client
can call a tool it listed minutes earlier; after a restart the client's
initialize-time tools/list repopulates the map.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JaFvfHrQyUKCGv6o3N2Wir
