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

With no annotations, the description carries the full burden, but it does add two real behavioral facts: the output includes timestamps and the call costs $0.03. It omits error conditions (missing/disabled captions), rate limits, and whether the operation is read-only (implied but not stated).

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, each earning its place: output shape, accepted input, and price. Front-loaded with the core purpose and no filler.

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?

There is no output schema, so the description should characterize the return payload, and it gives only a minimal hint ('full transcript with timestamps') without format, structure, or handling of missing transcripts. For a tool with no annotations and no output schema, this is adequate but leaves gaps.

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%, with both videoId and lang fully documented, so the schema does the heavy lifting. The description's 'Accepts a video ID or any YouTube URL' reinforces the videoId flexibility but adds no meaning beyond the schema baseline.

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 resource (YouTube video transcript) and verb-like action (returns the full transcript), plus scope 'any YouTube video' and format 'with timestamps'. It is unambiguous, though there is no sibling YouTube tool to distinguish it from, so the differentiation dimension is moot.

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 never says when to use this tool versus alternatives, nor any prerequisites (e.g. video must have captions). It only describes what the tool returns, leaving the agent to infer applicability on its own.

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