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

The description discloses a significant side effect: setting restates_canon to true causes ticks without a canon stamp to 'perish,' which is destructive behavior. This directly contradicts the annotation destructiveHint=false, which would lead an agent to believe no data destruction occurs. Therefore, the description contradicts annotations and must be flagged.

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?

Three sentences, each earning its place: purpose, partial-update behavior, and the critical restates_canon side effect. It is front-loaded with the main action and uses clear examples to explain consequences. No redundancy.

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?

The description is thorough for a 4-parameter update tool: it covers the purpose, the partial update model, key immutability, and the only notable side effect. It does not describe the return value, but no output schema exists and the tool's result is likely trivial. However, the annotation contradiction introduces confusion about the tool's safety profile, preventing a perfect completeness score.

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?

The schema covers all four parameters with descriptions, but the tool description adds critical semantic meaning: it explains that the 'check' key is immutable and preserved across renames, and that toggling restates_canon deletes unstamped ticks. This goes beyond the schema's description of restates_canon as a boolean and adds decision-making context.

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 function: correcting a check's label and restates_canon flag. It distinguishes from sibling add/delete/tick tools by focusing on modification of existing checks. The phrase 'Only what you send changes' clarifies the update scope.

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?

The description implies when to use this tool (to correct existing checks) without explicit alternatives. It gives the important guideline that only sent fields are updated, and explains the persistence of ticks on label changes. However, it does not explicitly name alternative tools or state when not to use it, so it falls short of a full usage guide.

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