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

Beyond the readOnlyHint annotation, the description adds meaningful behavioral disclosures: the exact meaning of a 404 and the explicit recommendation to consult get_transcripts_job, plus the 'Free' cost note. This goes well beyond what the schema or annotations already convey.

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 concise: three short sentences, each earning its place. The opening line gives the purpose, the second provides critical error semantics, and the third addresses cost. No filler or redundancy.

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 simple two-parameter input, a readOnly annotation, and an output schema, the description is complete. It covers purpose, differentiation, error handling, and cost, and refers to the right sibling tool for follow-up—leaving no critical gaps for an agent 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 clear descriptions for both job_id and video_id. The tool description does not need to repeat parameter details, but it also does not enrich them beyond the schema, so the 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 states a specific verb ('Read') and exact resource ('ONE video's result out of a batch job'), and clearly differentiates the tool from its plural sibling get_transcripts_results by saying 'without paging through get_transcripts_results.' This makes the purpose unambiguous and immediately distinguishable.

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 explains when to use this tool—when you need a single video result from a batch—and names the alternative 'get_transcripts_results' by advising against paging through it. It also provides important "do not assume worst case" guidance by telling agents to check get_transcripts_job on 404 before concluding anything.

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