Fetches pydantic-ai-common-pitfalls from existential-birds/beagle and configures it for Cursor.
3
Select Cursor when prompted
The CLI shows a list of agents. Use arrow keys and space to select Cursor:
◆ Which agents do you want to install to?
│
│ ── Universal (.agents/skills) ────────────────
│ · Cline · Codex · Goose · Windsurf
│ ●Cursor(selected)
│ · Cursor · Aider · Continue
4
Verify installation
Confirm successful installation by checking the skill directory location:
.cursor/skills/pydantic-ai-common-pitfalls
Restart Cursor to activate pydantic-ai-common-pitfalls. Access via /pydantic-ai-common-pitfalls in your agent's command palette.
⚠
Security Notice
We perform automated surface-level scans (Gen AI Scanner, Socket, Snyk) during installation. These checks detect common vulnerabilities but do not guarantee complete security. Always review skill source code and verify the publisher's reputation before production use.
Skills execute code in your environment. Always review source, verify the publisher, and test in isolation before production.
# ERROR: RunContext not allowed in tool_plain@agent.tool_plainasyncdefbad_tool(ctx: RunContext[MyDeps])->str:return"oops"# UserError: RunContext annotations can only be used with tools that take context
# ERROR: First param must be RunContext@agent.tooldefbad_tool(user_id:int)->str:return"oops"# UserError: First parameter of tools that take context must be annotated with RunContext[...]
# ERROR: RunContext must be first parameter@agent.tooldefbad_tool(user_id:int, ctx: RunContext[MyDeps])->str:return"oops"
Fix: RunContext must always be the first parameter.
Valid Patterns (Not Errors)
Raw Function Tool Registration
The following pattern IS valid and supported by pydantic-ai:
from pydantic_ai import Agent, RunContext
asyncdefsearch_db(ctx: RunContext[MyDeps], query:str)->list[dict]:"""Search the database."""returnawait ctx.deps.db.search(query)asyncdefget_user(ctx: RunContext[MyDeps], user_id:int)->dict:"""Get user by ID."""returnawait ctx.deps.db.get_user(user_id)# Valid: Pass raw functions to Agent(tools=[...])agent = Agent('openai:gpt-4o', deps_type=MyDeps, tools=[search_db, get_user]# RunContext detected from signature)
Why this works: PydanticAI inspects function signatures. If the first parameter is RunContext[T], it's treated as a context-aware tool. No decorator required.
Do NOT flag code that passes functions with RunContext signatures to Agent(tools=[...]). This is equivalent to using @agent.tool and is explicitly documented.
Dependency Type Mismatches
Wrong: Missing deps at runtime
agent = Agent('openai:gpt-4o', deps_type=MyDeps)# ERROR: deps required but not providedresult = agent.run_sync('Hello')# Missing deps!
Fix: Always provide deps when deps_type is set:
result = agent.run_sync('Hello', deps=MyDeps(...))
classResponse(BaseModel): count:int items:list[str]agent = Agent('openai:gpt-4o', output_type=Response)result = agent.run_sync('List items')# May fail if LLM returns wrong structure
Fix: Increase retries or improve prompt:
agent = Agent('openai:gpt-4o', output_type=Response, retries=3,# More attempts instructions='Return JSON with count (int) and items (list of strings).')
Complex nested types
# May cause schema issues with some modelsclassComplex(BaseModel): nested:dict[str,list[tuple[int,str]]]
Fix: Set environment variable or use defer_model_check:
# For testingagent = Agent('openai:gpt-4o', defer_model_check=True
Implementation Guide
Prerequisites
›Claude Desktop or compatible AI client with skill support
›Clear understanding of task or problem to solve
›Willingness to iterate and refine outputs
Time Estimate
15-45 minutes depending on use case complexity
Steps
1Install skill using provided installation command
2Test with simple use case relevant to your work
3Evaluate output quality and relevance
4Iterate on prompts to improve results
5Integrate into regular workflow if valuable
Common Pitfalls
⚠Expecting perfect results without iteration
⚠Not providing enough context in prompts
⚠Using skill for tasks outside its intended scope
⚠Accepting outputs without review and validation
Best Practices
✓ Do
+Start with clear, specific prompts
+Provide relevant context and constraints
+Review and refine all outputs before using
+Iterate to improve output quality
+Document successful prompt patterns
✗ Don't
−Don't use without understanding skill limitations
−Don't skip validation of outputs
−Don't share sensitive information in prompts
−Don't expect skill to replace human judgment
💡 Pro Tips
★Be specific about desired format and style
★Ask for multiple options to choose from
★Request explanations to understand reasoning
★Combine AI efficiency with human expertise
When to Use This
✓ Use when
Use when skill capabilities match your task, clear ROI on time saved, and you can validate outputs. Best for repetitive tasks, learning, and quality improvement.
✗ Avoid when
Avoid when task requires deep expertise you can't validate, involves sensitive decisions, or when learning process is more valuable than speed of completion.
Learning Path
1Familiarize yourself with skill capabilities and limitations
2Start with low-risk, non-critical tasks
3Progress to more complex and valuable use cases
4Build expertise through regular use and experimentation
