lc2mcp

lc2mcp is a Python adapter that converts existing LangChain tools (e.g., @tool functions, StructuredTool, BaseTool-derived tools) into FastMCP-compatible tools, registering them on a FastMCP server with optional context injection, docstring/args-schema handling, and namespace/collision management.

Evaluated Mar 30, 2026 (22d ago)
Repo ↗ DevTools mcp fastmcp langchain tooling python adapter server
⚙ Agent Friendliness
55
/ 100
Can an agent use this?
🔒 Security
39
/ 100
Is it safe for agents?
⚡ Reliability
24
/ 100
Does it work consistently?

Score Breakdown

⚙ Agent Friendliness

MCP Quality
70
Documentation
75
Error Messages
0
Auth Simplicity
60
Rate Limits
10

🔒 Security

TLS Enforcement
40
Auth Strength
35
Scope Granularity
20
Dep. Hygiene
55
Secret Handling
50

lc2mcp appears to provide context injection patterns but does not document a security model (auth schemes, scope enforcement, or secret-handling guarantees). TLS enforcement and transport security are not specified in the library README. Dependency hygiene is indeterminate from provided data; manifest includes several optional server dependencies including passlib/python-jose-like packages, but no evidence of vulnerability status or secure defaults is provided.

⚡ Reliability

Uptime/SLA
0
Version Stability
40
Breaking Changes
30
Error Recovery
25
AF Security Reliability

Best When

You already have LangChain tools and want to rapidly expose them as MCP tools with consistent JSON schema and optional runtime/context wiring.

Avoid When

You need a turnkey, centrally managed API with documented auth/rate limits/SLA; lc2mcp focuses on adaptation rather than operating a managed endpoint.

Use Cases

  • Expose existing LangChain tool ecosystem to MCP clients (e.g., Claude, Cursor) via FastMCP servers
  • Create MCP servers quickly from LangChain tools with minimal boilerplate
  • Inject authentication/user/app context and MCP context into tool execution
  • Standardize tool schemas via docstring parsing and/or Pydantic args_schema conversion

Not For

  • Producing a hosted SaaS MCP service out of the box (appears to be a local library/tooling layer)
  • Use as a standalone tool registry without understanding FastMCP server setup
  • Security-critical authentication/authorization enforcement unless you implement it in your own runtime/context layer

Interface

REST API
No
GraphQL
No
gRPC
No
MCP Server
Yes
SDK
No
Webhooks
No

Authentication

Methods: None specified by lc2mcp; auth is handled by the FastMCP server/user-supplied runtime_adapter/context
OAuth: No Scopes: No

README describes passing auth/user info via Context state and a runtime_adapter into LangChain ToolRuntime context, but does not specify an authentication scheme implemented by lc2mcp itself.

Pricing

Free tier: No
Requires CC: No

No pricing information provided; appears to be an open-source library distributed via PyPI.

Agent Metadata

Pagination
none
Idempotent
False
Retry Guidance
Not documented

Known Gotchas

  • lc2mcp is an adapter; actual runtime behaviors (auth, context, tool execution semantics) depend on your FastMCP server setup and your tool implementation
  • Parameter descriptions require parse_docstring=True or args_schema; otherwise schema may lack field descriptions
  • Name collision handling defaults to on_name_conflict='error'—agents should avoid assuming silent overwrites

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Scores are editorial opinions as of 2026-03-30.

8642
Packages Evaluated
17761
Need Evaluation
586
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