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 two genuinely useful behavioral facts not in the structured data: results are paginated at 25 per page, and each call consumes 1 credit — the cost signal is exactly the kind of context annotations cannot express.

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 short sentences, front-loaded with the purpose, then scope, then the two operational facts that matter most. No filler and nothing repeated from the title.

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?

For a 4-parameter search tool with no output schema, the description covers purpose, page size, and credit cost, which is enough to call it correctly in the happy path. It leaves 'sort' and 'cache_max_age' entirely unexplained and says nothing about what a result record contains or how to detect the last page.

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 only 50%: 'query' and 'cursor' are documented in the schema, but 'sort' (with its relevance/views/date enum) and 'cache_max_age' have no description anywhere. The description says nothing about sort ordering or cache behavior, so it fails to compensate for the coverage gap.

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 ('Search videos') and scopes it to Rumble, which separates it from the content-fetch siblings (rumble_video, rumble_channelVideos, rumble_comments, rumble_transcript). It does not explicitly name those siblings as alternatives, but the verb 'search' alone disambiguates within the rumble_ family.

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?

There is no explicit when-to-use or when-not-to-use guidance and no alternative named. 'Public Rumble video search results' hints that only public content is covered, but an agent must infer that from the adjective rather than from a stated rule.

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