The short project brief I use with coding agents

Telling a coding agent only to “add this feature” can produce a large change that works but does not fit the project. I structure tasks as:

• Goal and expected user behavior
• Files it may change and areas it must not touch
• Acceptance criteria and failure cases
• Existing test commands
• Security and backward-compatibility constraints
• A concise change summary after completion

I ask the agent to inspect the relevant code and tests first, state its assumptions, make a small change, and run lint and tests. Production secrets and real user data never belong in the task.