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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds meaningful behavioral context beyond that: the upstream slice cap of 100 and, crucially, that there is no usable continuation cursor, which tells the agent not to attempt pagination. It stops short of describing return shape, which the output schema likely covers.

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 tight sentences, front-loaded with the core operation, then the exclusion, then the operational constraint, then the alternatives. Every clause carries information; no 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?

With an output schema present, the description need not explain return values. Combined with annotations covering the safety profile and the schema documenting params, the description supplies all remaining context an agent needs: scope exclusion, the 100-row cap, the absent cursor, and sibling routing.

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 id, url, and limit are already documented. The description restates that lookup works by name 'id' or canonical name 'url' but adds no format or syntax detail beyond the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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 (fetch) and resource (public IMDb person-video metadata and thumbnail URLs), and explicitly scopes out what it does not return (playback URLs/media manifests). It distinguishes itself from imdb_title_videos, imdb_name_images, and imdb_name_credits by name.

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 routes the agent: 'Use imdb_title_videos for a title, imdb_name_images for photos, or imdb_name_credits for credits.' This gives clear alternatives and the condition that selects each, leaving nothing to inference.

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