Check a video

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

Annotations already declare readOnlyHint and closed-world, and the description adds meaningful context beyond them: it is non-rendering (cheap), it reports per-problem frames, and `ok: false` is the failure contract. It stops short of saying whether the 'pictures of the worst frames' are written to disk, which matters for a tool marked read-only.

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?

Front-loaded with the core action and the 'without rendering' qualifier, then the rule list, then the return/failure contract. The rule enumeration is long but each item is a distinct check, so it earns its space; only the run-on list construction costs a point.

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 correctly takes on the return-value burden by naming the JSON result, per-problem frames, and worst-frame images. It is nearly complete for a two-param read-only check, with only the on-disk side effects of the images left unstated.

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% and both parameters carry their own descriptions (folder with index.html, id from the JSON script block), so the schema does the work. The description adds no additional parameter semantics, making the baseline 3 correct.

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 and resource ('run automatic checks on every frame') and enumerates the exact rule set being validated. The phrase 'without rendering' cleanly separates it from the sibling `render`, so an agent can pick it without opening a schema.

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?

'fix and check again' implies an iterate-until-ok workflow, which is real guidance. However, it never says when to prefer this over `preview` or when to skip it and go straight to `render`, leaving the sibling routing to inference.

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