FastAPI Architect

An MCP server that gives Claude Code IDE-level intelligence for FastAPI projects — semantic code navigation, safe renaming, route inspection, dependency trees, and Pydantic model analysis.

Instead of Claude reading files blindly, it calls structured tools backed by Jedi (Python language server) and Python's AST.

Tools

Tool	Description
find_references	Find all usages of a symbol across the project
rename_symbol	Safely rename a symbol across all files
go_to_definition	Jump to where a symbol is defined
get_completions	Get completion suggestions at a cursor position
list_routes	List all FastAPI routes across the entire project
get_dependencies	Get the full Depends() injection tree for a handler
build_dependency_graph	Full graph: route → input models → dependencies → response model
validate_response_models	Detect routes missing a response_model declaration
list_models	List all Pydantic/SQLModel models in a file
inspect_model	Inspect a model's fields, types, defaults, and validators
find_model_usages	Find everywhere a model is used across the project
detect_schema_orm_mismatches	Detect field mismatches between ORM model and Pydantic schema

Installation

pip install fastapi-architect-mcp

Configuration

Option 1 — Global (available in all projects)

Add to ~/.claude/settings.json:

{
  "mcpServers": {
    "fastapi-architect": {
      "command": "fastapi-architect-mcp"
    }
  }
}

Option 2 — Per project (recommended for best results)

Create .mcp.json at your project root:

{
  "mcpServers": {
    "fastapi-architect": {
      "command": "/path/to/your/project/venv/bin/fastapi-architect-mcp"
    }
  }
}

Using your project's own venv gives Jedi access to all your project's dependencies, which enables full cross-file find_references and rename_symbol support.

Then restart Claude Code.

Usage examples

Once connected, you can ask Claude Code things like:

• "List all routes in this project"
• "What are the dependencies of the get_users handler?"
• "Find all references to get_db across the project"
• "Rename get_db to get_session everywhere"
• "Inspect the UserCreate model"
• "Are there any routes missing a response_model?"
• "Show me the full dependency graph for the users router"
• "Are there any mismatches between my User ORM model and UserPublic schema?"

Supported patterns

Dependency injection

• def handler(x=Depends(func)) — standard FastAPI
• def handler(*, x=Depends(func)) — keyword-only args
• @router.get("/", dependencies=[Depends(func)]) — decorator-level deps
• SessionDep = Annotated[Session, Depends(get_db)] — Annotated aliases (modern FastAPI)

Models

• BaseModel — Pydantic
• SQLModel — SQLModel
• BaseSettings — Pydantic settings
• RootModel — Pydantic v2
• Inherited models (e.g. class UserCreate(UserBase))

Validators

• @validator — Pydantic v1
• @field_validator — Pydantic v2

Known limitations

• find_references and rename_symbol work cross-file only when the MCP is configured to use the project's own venv (Option 2 above). With a global install, they only operate on the file where the symbol is defined.
• get_dependencies supports native FastAPI Depends() only. Other DI frameworks (Dishka, dependency-injector, etc.) are not supported.
• Runtime dependencies (middleware, lifespan events, startup hooks) are not visible to static analysis and won't appear in dependency trees.
• get_completions is most useful at attribute access positions (e.g. after a .). On empty lines it returns all Python builtins.

Requirements

• Python 3.11+
• Claude Code (VS Code extension or CLI)

Author

Abdessamad Touzani

• GitHub: @AbdessamadTzn
• LinkedIn: abdessamadtouzani