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MCP tool-source attribution

When your agent's tools come from Model Context Protocol servers (loaded via langchain-mcp-adapters), tracesage can attribute each tool call to the MCP server it came from — so you can see, at a glance, "these 10 tools came from 2 MCP servers; these 2 are hardcoded in my workflow."

Install

MCP support is an optional extra (the core package never imports it):

pip install 'tracesage[mcp]'

The [mcp] extra installs langchain-mcp-adapters>=0.1.0, mcp>=1.0.0, and langgraph. If you already manage those yourself, any langchain-mcp-adapters>=0.1.0 works.

Register tool sources

LangChain tools don't reliably carry their originating MCP server, so tracesage records the mapping explicitly. Do this once at setup, before invoking your graph:

from langchain_mcp_adapters.client import MultiServerMCPClient
from tracesage import TraceSage
from tracesage.adapters.mcp import register_mcp_client

tracer = await TraceSage.create()

client = MultiServerMCPClient({
    "weather": {"command": "python", "args": ["weather_server.py"], "transport": "stdio"},
    "math":    {"command": "python", "args": ["math_server.py"],    "transport": "stdio"},
})

# Loads every server's tools AND records tool -> server provenance.
mcp_tools = await register_mcp_client(tracer, client)

# Your own @tool functions stay "local" (unattributed) automatically.
all_tools = mcp_tools + [my_local_tool]

register_mcp_client is async (loading tools from MultiServerMCPClient is async). In a synchronous app, load + register inside an asyncio.run(...) startup block, then use the returned tools with your sync agent.

If you load tools per server yourself, attribute them explicitly (this call is sync):

from tracesage.adapters.mcp import register_mcp_tools
register_mcp_tools(tracer, weather_tools, server="weather")

Or register a single tool name:

tracer.register_tool_source("get_weather", "weather")

Auto-detection (best-effort)

Even without registration, tracesage tags a tool whose call carries metadata={"mcp_server_name": "..."}. Explicit registration is the reliable path; auto-detection is a fallback.

Where it shows up

  • UI — a "Tools by source" panel (top-right of the graph pane) groups tools as MCP: weather (4) · MCP: math (2) · Local (2). Clicking a tool node shows its source in the drawer.
  • REST — GET /api/tools returns the grouped inventory; topology tool nodes carry a source field. See the API reference.
  • Storage — provenance is persisted on each tool event (events.mcp_server), so it survives restarts and is visible in tracesage serve mode.

Tools by source panel

The "Tools by source" panel groups every tool as MCP math, MCP weather, or Local.

MCP server inspector

Clicking an MCP server node shows its invocations, errors, the tools it provides, and which agents use it.

Try it

A runnable end-to-end scenario (two local stdio MCP servers + two hardcoded tools, no API key) lives in examples/mcp/:

pip install 'tracesage[mcp]'
python examples/mcp/main.py    # then open http://localhost:7842/ui