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

With no annotations provided, the description carries the burden of behavioral disclosure and does so well: it states the 1-credit cost, that empty results and failures are not charged, and that cache=true provides a free 24h hit while default is always fresh. This goes beyond the schema and gives the agent actionable operational knowledge, though it does not cover rate limits or error formats.

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 three tight sentences with no filler. Each sentence contributes distinct value: output shape, pricing/charge policy, and cache behavior. The core purpose is front-loaded, and all content is relevant.

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?

Given the tool's low complexity (2 params, no output schema, no annotations), the description covers the essentials: what it returns, cost, failure behavior, and cache semantics. It could be more complete by explicitly pointing to rumble_video_transcript as the alternative for transcript text, but it is sufficient for an agent to invoke correctly.

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 description coverage is 100%, so the baseline is 3. The description adds value by clarifying the cache parameter's behavior — free 24h hit and default freshness — which augments the schema's more generic boolean description. The URL parameter is already thoroughly documented in the schema, including platform-matching constraints.

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 clearly identifies the resource as 'Rumble video metadata' and specifies the key output components (streams[], captions[], audioStreams), making the tool's function unmistakable. It also distinguishes itself from sibling tools like rumble_video_transcript and rumble_search by focusing on metadata rather than transcripts or search results.

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?

The description implies usage when metadata is needed rather than transcripts or search, and it gives explicit usage guidance for the cache parameter ('Pass cache=true for a free 24h cache hit'). However, it never names alternative tools or states when not to use this tool, leaving the decision to inference.

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