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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the description only needs to add context. It does: passing modelId changes the response shape to include supported settings and a full credit estimate, which the agent could not infer from annotations. Pagination and ordering behavior remain unstated.

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?

Two tightly packed sentences with zero filler; the enumeration of returned fields is front-loaded and the modelId drill-down behavior follows immediately.

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 output schema, the description carries the burden of describing returns and does so adequately, listing the per-model fields and the enriched payload when modelId is supplied. It stops short of covering ordering, pagination, or empty-result behavior, but nothing essential for a correct call 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?

Schema coverage is 100%, so the baseline is 3, but the description goes beyond the schema by explaining the semantic effect of modelId (returns that model's settings and full credit estimate) and confirming mediaType as a list filter rather than a required scoping value.

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 (lists models available for a workspace) and enumerates exactly what is returned: ID, label, provider, generation modes, and a credit estimate. No sibling tool does anything comparable, so an agent can select it unambiguously.

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?

Gives concrete routing guidance for its two modes: use mediaType to filter the list, and pass modelId to drill into a single model's supported settings. It does not state when not to use it or name an alternative, but no sibling overlaps this function.

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