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

Annotations already declare readOnly and idempotent, but the description adds substantial behavioral context: it discloses the return format (source_class, provenance, snapshot, pagination), the empty data array on no match, and the argument error on missing/invalid input. These are not implied by the annotations and give the agent precise expectations.

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 compact, front-loading the core purpose and then detailing behavior and requirements. It avoids fluff but includes some redundancy (e.g., 'Inputs: standard_number' and 'Required: standard_number') that could be trimmed. Overall it is well-structured and not overly verbose.

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 read-only metadata retrieval tool with a well-documented schema, the description covers the essential aspects: what it returns, what it does not return, empty result behavior, and error handling. Pagination mechanics are implied by 'paginated' and the schema's offset/limit/snapshot details, which is sufficient given the schema's richness. Minor gaps like the meaning of source_class/provenance are acceptable without an output schema.

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 100%, so every parameter is fully documented in the schema. The description adds minimal parameter-specific value beyond restating that standard_number is required and that invalid input yields an error, which is more about error behavior than parameter meaning. Baseline 3 is appropriate given the schema's thoroughness.

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 retrieves standard metadata given a known standard number, and explicitly distinguishes it from returning full text. It also names the primary input (standard_number) and the output type (paginated structured records), making its purpose unambiguous and differentiating it from search tools like search_standard_metadata.

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 provides a clear usage condition: use when the recorded standard number is known. It also clarifies what the tool does not do ('no standard full text'), implicitly steering users to other tools for full text. However, it does not explicitly name alternative tools or state when not to use it beyond that condition, so it stops short of full guidance.

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