Validation messages

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

Annotations already provide readOnlyHint=true and openWorldHint=true. The description adds behavioral value by disclosing that setting recheck=true triggers a fresh 'Recheck accounting' operation before returning results, which is not obvious from the schema alone. No contradictions with 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 two sentences, front-loaded with the primary purpose, and the second sentence explains the optional recheck behavior. Every word earns its place with 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?

For a simple tool with two optional parameters and no output schema, the description provides sufficient context: what it returns (list of messages as JSON array), and the key behavioral option (recheck). No critical information is missing.

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 already documents both parameters with 100% coverage. The description adds extra semantic value for the recheck parameter by explaining its effect ('force a fresh Recheck accounting'), going beyond the schema's 'When true, run Recheck accounting first.'

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: 'Return the list of accounting validation/error messages as a JSON array.' This is a specific verb+resource combination that distinguishes it from the sibling tool banana_messages_count, which likely returns only a count.

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 guidance on when to set recheck=true ('to force a fresh Recheck accounting'), but it does not explicitly state when to use this tool versus alternatives or mention the sibling count tool. The usage context is implied rather than fully explicit.

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