Imported from chaochaoxiaochao/pi-toolkit (global/AGENTS.md). Install upstream with npx skills add chaochaoxiaochao/pi-toolkit --skill global. Copyright stays with the author.

AGENTS.md

Behavioral guidelines to reduce common LLM coding mistakes. Merge with project-specific instructions as needed.

Tradeoff: These guidelines bias toward caution over speed. For trivial tasks, use judgment.

1. Think Before Coding

Don't assume. Don't hide confusion. Surface tradeoffs.

Before implementing:

• State your assumptions explicitly. If uncertain, ask.
• If multiple interpretations exist, present them - don't pick silently.
• If a simpler approach exists, say so. Push back when warranted.
• If something is unclear, stop. Name what's confusing. Ask.
• If requirements conflict (e.g., durability vs latency, correctness vs speed), name the conflict explicitly. Never average conflicting requirements into something that satisfies neither.

2. Simplicity First

Minimum code that solves the problem. Nothing speculative.

• No features beyond what was asked.
• No abstractions for single-use code.
• No "flexibility" or "configurability" that wasn't requested.
• No error handling for impossible scenarios.
• If you write 200 lines and it could be 50, rewrite.

Ask yourself: "Would a senior engineer say this is overcomplicated?" If yes, simplify.

3. Surgical Changes

Touch only what you must. Clean up only your own mess.

When editing existing code:

• Don't "improve" adjacent code, comments, or formatting.
• Don't refactor things that aren't broken.
• Match existing style, even if you'd do it differently.
• If you notice unrelated dead code, mention it - don't delete it.

When your changes create orphans:

• Remove imports/variables/functions that YOUR changes made unused.
• Don't remove pre-existing dead code unless asked.

The test: Every changed line should trace directly to the user's request.

When fixing a bug, fix the root cause, not the symptom. Find where the defect actually lives:

• Grep every caller of the function you touch; a report names a symptom, and patching only the path the ticket mentions leaves sibling callers still broken.
• If the shared function is wrong, fix it once - do not scatter per-caller guards.
• If one caller is wrong, fix that caller - do not add defensive handling to a correct shared function.

4. Goal-Driven Execution

Define success criteria. Loop until verified.

Transform tasks into verifiable goals:

• "Add validation" -> "Write tests for invalid inputs, then make them pass"
• "Fix the bug" -> "Write a test that reproduces it, then make it pass"
• "Refactor X" -> "Ensure tests pass before and after"

For multi-step tasks, state a brief plan:

1. [Step] -> verify: [check]
2. [Step] -> verify: [check]
3. [Step] -> verify: [check]

Strong success criteria let you loop independently. Weak criteria ("make it work") require constant clarification.

5. Read Before You Write

Understand adjacent code before changing it. "Looks orthogonal" is a dangerous assumption.

Before adding code to any file:

• Read the file's exports and public API.
• Read the immediate callers of the function you're modifying.
• Check shared utilities in the same module.
• If you're unsure why code is structured a certain way, ask before writing.

6. Fail Visibly, Not Silently

Silent skips are failures. Surface uncertainty instead of hiding it.

• "Completed" is wrong if anything was silently skipped.
• "Tests pass" is wrong if any test was skipped.
• Default to surfacing uncertainty. When in doubt, over-communicate what you're unsure about.
• If a required input, file, or tool is missing (or a step is impossible under the stated constraints), do NOT fabricate it to make a check pass. Report what is missing and what you need.

7. Reuse Before Writing

Before writing new code, check in order:

1. Does it already exist in this codebase? Reuse it - do not re-implement it yourself, even with the standard library. (If the existing helper is itself the bug, fix it once - see Rule 3.)
2. Does the standard library cover it? Use it.
3. Only then: write the minimum code that works.

8. Use Available Editing Tools

Follow the current harness's tool surface; do not assume a shell patch helper exists.

• Use the native file-editing tools exposed by the current environment. In pi, use edit for precise replacements and write for new files or complete rewrites.
• Do not run apply_patch as a shell command unless command -v apply_patch confirms that executable is available.
• If the harness exposes apply_patch as a dedicated tool rather than a command, invoke it only through that tool interface.