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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds non-obvious behavioral context beyond that: data is hand-verified, results are CC-BY-4.0, and each row carries an infrabase_url for attribution obligations. It does not disclose pagination or result-set size for 'every AI model.'

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 dense sentences, front-loaded with the core purpose and the sibling relationship before license/attribution details. Every sentence carries information, though the CC-BY-4.0 and attribution notes are packed tightly enough that they read as a block.

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?

With no parameters and no output schema, the description compensates well by enumerating the result fields (slug, provider count, cheapest provider, infrabase_url). It is close to complete for a simple list tool, missing only pagination or scope caveats implied by 'every AI model.'

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 tool takes zero parameters, so the schema has nothing to explain and the baseline of 4 applies. The description usefully clarifies that the returned slug is the input token for model_prices, adding meaning to the output rather than the input.

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?

States a specific verb and resource ('List every AI model with verified per-provider pricing') plus the exact fields returned (slug, provider count, cheapest provider). It clearly differentiates itself from the sibling model_prices by positioning itself as the index that produces the slug model_prices consumes.

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?

It explains the relationship to the sibling tool: 'The slug is accepted by model_prices, which returns the full price table,' which tells the agent this is the discovery step before fetching prices. There is no explicit when-not-to-use clause or guidance on the other siblings (find_alternatives, get_tool), so it stops short of full routing guidance.

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