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

The annotations already mark the operation read-only, idempotent, and non-destructive. The description adds genuinely useful behavioral context beyond annotations: the API key requirement, the exact status vocabulary, and the returned fields (video URL, credits charged). No contradiction with annotations.

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 front-load the core purpose and then provide essential auth setup context. The auth instruction is a bit long but is operationally important for the agent, and there is no redundant filler.

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 single-parameter read-only lookup with an output schema present, the description covers what the tool does, what it returns, and the required authorization. An agent has everything needed to invoke it correctly.

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%, with the parameter already documented as 'The id returned by generate_video.' The tool description adds no additional parameter-level meaning beyond what the schema provides, so the baseline 3 applies.

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 precise verb ('Check'), a specific resource ('one generation by id'), and the exact data returned: status values, finished video URL, and credits charged. This clearly distinguishes it from list_generations and generate_video.

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 makes clear it is a single-record lookup by id, especially with the schema note that the id comes from generate_video, which implies polling after generation. It does not explicitly name alternatives or state when not to use it, but the context is unambiguous.

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