{"version":"2.1.309","anchor":"mcp-handed-listings-config-can-carry-handed-listing-with","canonical_anchor":"headless-mcp-can-accept-a-handed-over-tool-listing-for-one-d","heading":"MCP config files are tracked, and a host can hand over a ready-made tool listing","tier":"use","area":"MCP","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.309\/e\/mcp-handed-listings-config-can-carry-handed-listing-with","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.309","markdown":"### MCP config files are tracked, and a host can hand over a ready-made tool listing\n\n--mcp-config file paths are now recorded and registered, and an MCP config can carry a pre-supplied tool listing so discovery can be skipped\n\n**Unclear.** It is not clear what supplies handed_listing or whether this is switched on for ordinary local sessions.\n\n**What**\n\nMCP servers are outside programs that give Claude Code extra tools. `--mcp-config` is the option that loads them from JSON files or strings. Two related things changed in how this configuration is read:\n\n- File paths: the paths of files given to `--mcp-config` are now kept for the whole session (`flagMcpConfigFilePaths`, cleared on reset). For each one that is a file, both the path and its real location on disk are collected and passed to a new registration step, which checks them against the scan of allowed folders. Before, the file was read with no path registration.\n\n- Handed listings: a server's config can now include a `handed_listing` string next to its `url`. The parser returns these as `handedListings`, and startup passes them on as `handedMcpListings`. In headless mode, a listing (its startup handshake plus `tools_list`, with an `at` timestamp) is accepted only for a dynamic http server whose URL matches. A listing older than 600 seconds is dropped. When connecting, cached servers can now have their capabilities, server details and instructions filled from a stored handshake. What supplies this data and whether it is switched on was not traced.\n\n**Why**\n\nA program hosting Claude Code can hand over a server's tool list ahead of time, so Claude Code can skip asking the server for it, which affects how quickly tools are available at startup.\n\n- Area: MCP\n- Names: `handed_listing`\n- Tier: Use it now\n- Useful: 4\/5\n- Signal: 3\/5\n- Scope: individual\n- Heads-up: no"}