Author: Jonas Devlieghere Date: 2025-06-30T09:01:15-07:00 New Revision: 16dc6f64ded3f47a6c03098e021ae943714a7663
URL: https://github.com/llvm/llvm-project/commit/16dc6f64ded3f47a6c03098e021ae943714a7663 DIFF: https://github.com/llvm/llvm-project/commit/16dc6f64ded3f47a6c03098e021ae943714a7663.diff LOG: [lldb] Document MCP support in LLDB (#145935) Document how to use MCP support in LLDB. I expect this to change significantly as the feature matures. For now it covers configuring the server and two example clients. Added: lldb/docs/use/mcp.md Modified: lldb/docs/index.rst Removed: ################################################################################ diff --git a/lldb/docs/index.rst b/lldb/docs/index.rst index 1ffdb08a1ca2c..d49d0d8d5a733 100644 --- a/lldb/docs/index.rst +++ b/lldb/docs/index.rst @@ -135,6 +135,7 @@ interesting areas to contribute to lldb. use/ondemand use/aarch64-linux use/symbolfilejson + use/mcp use/troubleshooting use/links Man Page <man/lldb> diff --git a/lldb/docs/use/mcp.md b/lldb/docs/use/mcp.md new file mode 100644 index 0000000000000..e7e78f7a28c7a --- /dev/null +++ b/lldb/docs/use/mcp.md @@ -0,0 +1,85 @@ +# Model Context Protocol (MCP) + +LLDB supports the [Model Context Protocol][https://modelcontextprotocol.io] +(MCP). This structured, machine-friendly protocol allows AI models to access +and interact with external tools, for example debuggers. Using MCP, an AI agent +can execute LLDB commands to control the debugger: set breakpoints, inspect +memory, step through code. This can range from helping you run a specific +command you cannot immediately remember, to a fully agent-driven debugging +experience. + +## MCP Server + +To start the MCP server in LLDB, use the `protocol-server start` command. +Specify `MCP` as the protocol and provide a URI to listen on. For example, to +start listening for local TCP connections on port `59999`, use the following +command: + +``` +(lldb) protocol-server start MCP listen://localhost:59999 +MCP server started with connection listeners: connection://[::1]:59999, connection://[127.0.0.1]:59999 +``` + +The server will automatically stop when exiting LLDB, or it can be stopped +explicitly with the `protocol-server stop` command. + +``` +(lldb) protocol-server stop MCP +``` + +The commands will fail if a server is already running or not running +respectively. + +## MCP Client + +MCP uses standard input/output (stdio) for communication between client and +server. The exact configuration depends on the client, but most applications +allow you to specify an MCP server as a binary and arguments. This means that +you need to use something like `netcat` to connect to LLDB's MCP server and +forward communication over stdio over the network connection. + +``` +┌──────────┐ ┌──────────┐ ┌──────────┐ +│ │ │ │ │ │ +│ LLDB ├─────socket────┤ netcat ├─────stdio─────┤MCP Client│ +│ │ │ │ │ │ +└──────────┘ └──────────┘ └──────────┘ +``` + +Configuration example for [Claude Code][https://modelcontextprotocol.io/quickstart/user]: + +```json +{ + "mcpServers": { + "tool": { + "command": "/usr/bin/nc", + "args": ["localhost", "59999"] + } + } +} +``` + +Configuration example for [Visual Studio Code][https://code.visualstudio.com/docs/copilot/chat/mcp-servers]: + +```json +{ + "mcp": { + "servers": { + "lldb": { + "type": "stdio", + "command": "/usr/bin/nc", + "args": ["localhost", "59999"] + } + } + } +} +``` + +### Troubleshooting + +The MCP server uses the `Host` log channel. You can enable logging with the +`log enable` command. + +``` +(lldb) log enable lldb host +``` _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
