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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is clear. The description adds no extra behavioral details such as error handling, rate limits, or return format. Since the annotations cover the safety aspects, the description's silence is acceptable, but it doesn't add beyond what annotations provide. No contradiction exists.

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 a single, focused sentence with no filler. It front-loads the core action ('Get metadata') and the method ('by URL'), making it easy to parse. Every word serves a purpose, and it is appropriately concise for such a simple tool.

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 tool with a single parameter, no output schema, and annotations covering safety, this description is complete. It tells the agent exactly what the tool does and what input is required. No additional context is needed to invoke it correctly, as the operation is straightforward and side-effect-free.

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% because the only parameter 'url' is described as 'Link to the Rumble video.' The description itself adds no additional meaning beyond the schema. Since the schema already documents the parameter adequately, the baseline of 3 applies; the description does not enrich the parameter semantics.

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: 'Get metadata for a Rumble video by URL'. It clearly identifies the operation and the resource type. While it doesn't explicitly differentiate from sibling tools like rumble_video_comments_list or rumble_video_transcript_get, the phrase 'metadata' implies a distinct scope, and the presence of 'by URL' distinguishes it from list/search tools. The purpose is clear, though not fully disambiguated from other Rumble video tools.

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?

No guidance on when to use this tool versus alternatives. It doesn't mention when to use it over rumble_video_comments_list or rumble_video_transcript_get, nor does it state any prerequisites or exclusions. An agent must infer that this tool is for basic metadata only, which could lead to incorrect tool selection when comments or transcripts are needed.

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