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

Annotations already declare readOnly/idempotent/non-destructive, so the safety bar is covered. The description adds genuinely useful non-obvious traits: media links expire after 15 minutes, shared downloads happen off-tool, and returned text is untrusted and wrapped in <untrusted_source_text>. It stops short of describing result size or failure modes, 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?

Front-loaded with purpose and the catalog split, then pagination, then the expiry caveat. Dense but nearly every sentence carries operational value; the two catalog clauses are slightly verbose for the space they take.

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, return values needn't be explained, and the description still covers modes, filtering, paging, link lifetime and untrusted content. Nothing an agent needs to call this correctly is missing.

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 baseline is 3, but the description adds meaning beyond the schema for catalog (what each mode searches and returns) and ties cursor/limit into a coherent paging model. Query matching semantics (whole words, no stemming) are echoed from the schema rather than extended.

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+resource ("Searches B-roll videos and images") and immediately distinguishes the two catalog modes and what each returns. An agent can tell this apart from get_broll_asset, which is explicitly named as the refresh path.

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?

Gives concrete when-to-use routing for catalog=mine vs shared, notes shared items are downloaded on the website, and names the alternative get_broll_asset with the condition (expired links) that selects it. Omit-query behavior is also stated.

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