src/mcp/

Responsibility

Define and expose the built-in MCP endpoints (websearch, context7, grep.app) alongside the shared type aliases so the application can treat remote and local MCPs uniformly (src/mcp/index.ts, src/mcp/types.ts).
Provide a single entry point (createBuiltinMcps) for instantiating the default connectors while honoring feature flags/disabled lists.

types.ts defines the discriminated union McpConfig with RemoteMcpConfig and LocalMcpConfig, keeping the shape of every connector explicit and easy to validate at compile time.
Each service file exports a RemoteMcpConfig literal that points at the remote URL and optionally supplies headers derived from the corresponding environment variable to avoid leaking secrets (websearch.ts, context7.ts, grep-app.ts).
index.ts aggregates the built-in configs in a Record<McpName, McpConfig> and exposes helpers/types for external consumers, keeping the set of hard-coded MCPs centralized.

On startup createBuiltinMcps iterates over the in-module registry and filters out any MCP listed in disabled_mcps, returning the remaining configs as a string-keyed record for the higher-level stack (src/index.ts).
Each remote config is evaluated eagerly, so the only per-request variability is the disabled_mcps list and the presence of environment-provided API keys for headers.

src/index.ts imports createBuiltinMcps to construct the MCP map used by the runtime, passing the user/cli-configured disabled_mcps array.
Types exported from src/mcp/types.ts are re-exported by src/mcp/index.ts, letting other modules reference McpConfig, LocalMcpConfig, and RemoteMcpConfig without reaching into individual files.
Remote configs are pure data objects consumed by the runtime's MCP execution layer (via the McpConfig contract) and depend only on environment-provided credentials and the URLs defined here.