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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower. The description still adds real context beyond them: 'Nothing is written', the '$0' cost, and the semantics of in-progress/refused uploads with their stage and reason. It does not cover pagination or freshness ordering beyond 'limit', so not a 5.

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?

Information-dense and front-loaded: return fields come first, then parameter roles, then the write/cost disclaimer. No wasted sentences, though the em-dash-heavy packing makes it slightly dense to parse.

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 usefully enumerates the returned fields (assetId, size, duration, usage count, upload stage/reason), covering the return contract. Cost and no-write behavior are stated, making it largely complete for a 4-param read tool, missing only ordering/pagination specifics.

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 the baseline is 3. The description restates each parameter's effect (kind keeps one kind, asset_id adds the content hash, handle returns upload state), which marginally reinforces the schema but adds little that isn't already documented there.

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 names a specific resource (the creator's own material in the personal library) and enumerates exactly what is returned — assetId, kind, filename, declarations, size, duration, usage count — plus the uploads section. It is clearly distinct from list_cast/list_ops/list_projects, though it never names a sibling to route against, so it falls 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?

It implicitly tells the agent which parameter to use for which goal (kind filters by type, asset_id fetches one file with hash, handle fetches one upload state), which is useful routing. But there is no explicit when-to-use/when-not-to-use guidance or named alternative, leaving usage to inference.

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