diff_chapter_contract

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are present, so the description bears full responsibility for behavioral disclosure. It states the tool performs a comparison but does not specify side effects, permissions, or whether it is read-only. The return format or potential errors are not addressed.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence that front-loads the action. It avoids repetition and every word contributes meaning. Minor improvement could be structuring with bullet points for clarity, but current form is acceptable.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 3 parameters with no schema descriptions, no output schema, and no sibling differentiation, the description is insufficient. It does not explain return values, error conditions, or how the comparison results are structured. The tool's complexity suggests a need for more detail.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% (no parameter descriptions), so the description must compensate. It adds context about what is compared (beats, checks, moves, markers) but does not explain the parameters 'file', 'chapter', or 'project_dir' (e.g., how 'file' relates to the chapter file). Baseline is 4; partial compensation reduces to 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's action: 'Compare a chapter file with visible required beats, acceptance checks, forbidden moves, and future markers.' It identifies the specific resource (chapter file) and the aspects being compared, distinguishing it from siblings like 'diff_proposal' which deals with proposals.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives. There is no mention of prerequisites, exclusions, or typical use cases, leaving the agent to infer context from the sibling names alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.