ctx mcp

ctx mcp serve runs a Model Context Protocol server over stdio. Compatible MCP clients (Claude Code, Cursor, opencode, MCP Inspector) can connect and call ctx pipelines as tools.

Subcommands

ctx mcp serve      # long-running stdio server
ctx mcp tools      # list exposed tools (debug)

Tools exposed

Tool	Wraps	Use case
ctx_exec	pipelines::exec::run_proxy_capture	Run a shell command with compression
ctx_search	pipelines::catalog::search	Semantic search in a catalog
ctx_map	pipelines::map::run	Generate a repo map
ctx_list	pipelines::catalog::list_collections	List indexed catalogs
ctx_graph_index	pipelines::graph::index	Index the symbol graph
ctx_callers	pipelines::graph::callers	Who calls symbol X?
ctx_callees	pipelines::graph::callees	What does symbol X call?
ctx_trace	pipelines::graph::trace	Caller chain up to depth
ctx_impact	pipelines::graph::impact	What breaks on change?
ctx_node	pipelines::graph::node	Where is X defined?

How it’s registered with Claude Code

ctx install --agent claude-code writes this into ~/.claude/settings.json:

{
  "mcpServers": {
    "ctx": {
      "command": "ctx",
      "args": ["mcp", "serve"],
      "_installer": "ctx"
    }
  }
}

The _installer: "ctx" marker lets ctx uninstall remove only our entries without touching MCP servers added by other tools.

Manual test

# Send initialize + tools/list to a running ctx mcp serve
(
  echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"0.1"}}}'
  echo '{"jsonrpc":"2.0","method":"notifications/initialized"}'
  echo '{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}'
  sleep 1
) | ctx mcp serve

Implementation

Built on top of rmcp 1.7 with schemars 1.0 for automatic JSON schema generation. Each tool is an async fn annotated with #[tool(...)] and the schema is derived from the input struct.

See src/integrations/mcp/server.rs for the full implementation (~250 lines for all 10 tools).