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

Annotations already declare readOnlyHint=true, destructiveHint=false, so the agent knows it's a safe read. The description adds meaningful behavioral context by explaining the nature of the output: it includes the identification class and confidence score, and it clarifies that confidence is 'an editorial judgement, not a probability.' This goes beyond the schema and annotations, providing critical interpretive guidance on how to treat the returned data.

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 efficient and front-loaded. The first sentence states the core function and output fields, immediately followed by usage guidance. The additional details on identification classes and confidence score are placed after the core purpose, ensuring the most critical information comes first. Every sentence serves a purpose, either clarifying the output or how to interpret it.

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 the tool's moderate complexity (single parameter, no required fields), the description is complete. It explains the output fields, the meaning of identification classes, and the confidence rubric. Since an output schema exists, the return structure is likely already documented, and the description fills the interpretive gaps. The agent has enough to call the tool correctly and interpret results.

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 coverage is 100%, meaning the schema documents the `locale` parameter with a default and enum. The description does not repeat this but adds a value by explaining the output's language configuration. However, this is minimal and the schema does most of the work, so a baseline of 3 is appropriate.

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 purpose: listing every place in the Homeric Atlas with its identification class, confidence score, and competing identifications. It distinguishes itself from sibling tools like `get_homeric_place` by defining the list action versus the get action, and it specifies the resource (places in the Homeric Atlas) without ambiguity.

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 explicitly instructs when to use this tool ('Use this to browse the atlas') and when to use an alternative ('use `get_homeric_place` once you have a slug'). This direct routing to the sibling tool is clear and actionable, leaving no inference needed.

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