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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds valuable behavioral detail by stating it returns 'valid:true/false plus a field-by-field error list' and enumerates the schema constraints being checked, which is context beyond the annotations.

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 front-loaded with the core validation purpose and schema name, then packs necessary field and return details into a dense but efficient two-sentence block. Every sentence contributes.

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?

There is no output schema, but the description explains the return shape ('valid:true/false plus a field-by-field error list'). Combined with the schema constraints and the sibling pairing hint, an agent has everything needed to invoke and interpret the tool.

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 has 100% description coverage for the single 'definition' parameter but only describes it generically as an object. The description compensates by enumerating the expected CHECKRUN-1 fields (definition_id, title, semver version, steps[], evidence_requirement enums, gate enums), adding substantial meaning beyond the schema.

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 states a specific verb and resource ('Validates a checklist or SOP definition JSON') and names the exact schema ('CHECKRUN-1'). It is clearly distinguishable from siblings like checklist_step_receipt and checklist_verify_run, which perform different actions.

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 gives a clear usage context by saying to 'Pair with checklist_step_receipt to run the definition headlessly', implying it is a pre-execution validation step. However, it does not explicitly state when not to use it or contrast it directly with checklist_verify_run.

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