Avoid common custom-agent pitfalls
Replace vague personas, accidental tool access and contradictory instructions with focused responsibilities.
A persona that is too broad
"You are a software engineer" says little about the expected work. Specify expertise, review criteria and output format. Split unrelated responsibilities when their permissions or success criteria differ.
Tools that are not deliberate
The infographic warns about missing tools, but its implication needs qualification: in GitHub's shared profile reference, omitting tools enables all available tools by default, rather than disabling them. Use an explicit allowlist to avoid unintended access.
The pictured codebase and terminal labels are not a portable allowlist. Confirm supported tool identifiers in the target client.
Conflicting or monolithic guidance
Agent instructions should complement repository standards. Resolve contradictions such as tabs versus spaces instead of asking the model to guess.
Avoid one agent responsible for security, tests, documentation and deployment with unrestricted tools. Prefer focused roles with clear handoffs and reusable skills.
Check tool defaults and aliases before using any illustrated example.