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

Annotations already declare readOnlyHint/idempotentHint/openWorldHint=false, so safety is covered; the description adds that the call is workspace-scoped and that the modelId path returns a richer payload (aspect ratios, resolutions, durations, reference limits). No pagination or auth notes, but for a read-only list this is solid added context.

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 sentences, no filler, with the primary list behavior front-loaded and the modelId detail path second. Every clause carries information about either output fields or parameter behavior.

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 usefully enumerates what the list returns and what the modelId detail mode returns, which is the main completeness requirement here. Minor gaps (no mention of empty results, pagination, or error cases) keep it short of a 5.

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?

mediaType has an enum but no schema description, and the description supplies its meaning as a filter; modelId's schema text is reinforced by explaining that it triggers the detail payload. workspaceId's scoping is already in the schema and the description confirms it, so coverage of the less-documented params is genuinely improved.

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 (Lists) and resource (models) scoped to a workspace, and enumerates the returned fields (ID, label, provider, generation modes, credit estimate). It also distinguishes the two modes of the call, so an agent knows it can either enumerate models or drill into one.

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?

Explicitly tells the agent to filter by mediaType and to pass modelId to get that model's supported settings and full credit estimate — a clear statement of the two usage paths. It does not name exclusions or when not to use it, but the conditional guidance is direct and actionable.

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