Validates the MCP-client loop end-to-end against one real MCP server before
the full v1.15 port. New services/mcp-client.ts wraps @modelcontextprotocol/sdk
v1.29.0 with Streamable HTTP transport. On startup (when MCP_CONTEXT7_URL is
set), connects to Context7, discovers tools via tools/list, wraps each as a
ToolDef prefixed context7_<name>, and appends to ALL_TOOLS via appendMcpTools.
Read-only invariant guard rejects any tool with readOnlyHint: false. Tool
dispatch is transparent — executeToolCall routes MCP calls through the ToolDef
execute wrapper, which strips the prefix before calling the MCP server. Result
size capped at 5MB with truncation. Graceful degradation: server down at
startup → zero tools; server down mid-session → error result, model
self-corrects.
Adversarial review caught that a Zod .default() on the URL config made MCP
always-on instead of opt-in — fixed by removing the default. MCP_CONTEXT7_URL
must be explicitly set to enable.
ALL_TOOLS changed from ReadonlyArray to mutable to support late-registration.
appendMcpTools re-sorts and rebuilds TOOLS_BY_NAME after append.
348/348 server tests passing (16 new mcp-client tests). No schema changes,
no frontend changes.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
