video_info

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

With no annotations, the description carries the full behavioral burden, and it excels: it discloses that full scans are 'exhaustive and therefore slow,' that results are 'cached and reused,' that force recomputes, and that a full scan may 'exceed the limit' of the per-call time budget. It also states a non-behavior of the tool (no images, so image limits don't apply). This is model-level transparency for a tool with zero annotation coverage.

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 longer than average but each clause earns its place: purpose, the two modes with their performance profiles, caching, force, image-limit exemption, and timeout risk. It is front-loaded with the definition before moving to behavior and caveats, and no sentence is redundant with the schema.

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?

The output schema already documents the return shape, so the description does not need to list response fields. What remains is well covered: mode selection, performance, caching, time limits, and the boundary against an image-returning sibling. The only meaningful omission is the format of the video input itself, which matters for call success.

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 0%, so the description must compensate, and it does for two of the three parameters: detail is fully explained with concrete consequences of each enum value, and force is tied to the caching behavior ('Use force=true to recompute'). The required video parameter is never described — its format, source, or accepted identifiers are left to inference from the parameter name alone — which is the only gap preventing a 5.

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 identifies the resource (video) and the core action (reading metadata) through the opening clause and the detailed account of what each detail level retrieves — container headers, scene cuts, silence intervals, and loudness. It differentiates from the sibling view_frames by explicitly noting it 'returns no images,' allowing an agent to tell them apart. The verb is implied rather than stated (a noun phrase opens the description), keeping this just short of a 5.

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 gives clear internal routing guidance: basic for immediate header-only reads, full when deep analysis is wanted, and force=true when the cached scan must be recomputed. It also warns when the tool is not appropriate — when a call risks exceeding the client time limit — and notes that image limits are irrelevant since no images are returned. It does not name the sibling explicitly or state 'use view_frames when you need images,' so it falls just short of explicit when-not/alternatives guidance.

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