{"version":"2.1.284","anchor":"mcp-request-header-hook-added-for-cli-owned-mcp-configs-but","canonical_anchor":"mcp-request-header-hook-added-for-cli-owned-mcp-configs-but","heading":"MCP connections gain an unused hook for adding per-request headers","tier":"soon","area":"MCP","url":"https:\/\/changelogs.core-directive.com\/v\/2.1.284\/e\/mcp-request-header-hook-added-for-cli-owned-mcp-configs-but","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.284","markdown":"### MCP connections gain an unused hook for adding per-request headers\n\nClaude Code-owned MCP configs can now register a provider that adds headers to each request, but nothing in this build registers one\n\n**Unclear.** It is not clear which future feature will use this or exactly which MCP connections it will apply to.\n\n**What**\n\nMCP servers are outside tools and services Claude Code can connect to. For the MCP connections Claude Code sets up itself, a new way to add extra HTTP headers (small labelled values sent with each request) has been built in:\n\n- The registration helper now accepts a `requestHeaders` option and stores it in a new `cliOwnedRequestHeaderProviders` WeakMap, next to the existing providers for the login token (`resolveBearerToken`) and for watching responses (`onResponse`).\n\n- Both Design MCP request wrappers now call that provider with the request's method and body, and merge the headers it returns into each request. They never replace a header that is already set, and never replace `Authorization`.\n\n- None of the code in this build that registers these configs passes `requestHeaders`; the callers pass only `getBearerToken` or nothing. So the hook exists but is not used yet.\n\n**Why**\n\nNothing changes for users in this build. The hook makes it possible later to tag individual MCP requests with extra headers, and because the request body is handed to it, the headers can depend on what is being sent.\n\n- Area: MCP\n- Tier: Nothing to try yet\n- Useful: 2\/5\n- Signal: 3\/5\n- Present in the build but not switched on"}