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

With no annotations provided, the description carries the full burden of behavioral disclosure. It covers pricing ('2 credits/min of audio'), failure handling ('Empty results and failures are never charged'), and cache behavior ('cache=true for a free 24h cache hit, default always fresh'). It does not describe the output format, but the operational cost and failure semantics are well disclosed.

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 two concise sentences that front-load the core purpose, then pack pricing, failure policy, and cache behavior into efficient clauses. Every sentence earns its place; no redundant or filler content.

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 absence of annotations and output schema, the description does well by covering cost, failure charging, cache behavior, and when to use the tool. It leaves the exact return format unstated, but the name and 'transcript' purpose make the output reasonably predictable. The rich input schema compensates for the remaining 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 description coverage is 100%, so the baseline is 3. The description adds valuable pricing context ('2 credits/min') that directly informs the maxCredits parameter, and clarifies the cache parameter's practical benefit. While cache details already exist in the schema, the credit-cost framing goes beyond the schema's own text.

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 opens with 'Speech-to-text for YouTube audio', a specific verb plus resource, and clearly differentiates itself from caption-based tools by noting it captures what was actually spoken rather than YouTube's published captions. This makes it distinguishable from sibling tools like youtube_transcript and video_transcript without needing to inspect their schemas.

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 gives explicit when-to-use guidance: 'Use it when a video has no captions — or when you want a transcript of what was actually spoken rather than YouTube's published captions.' It clearly implies an alternative caption-based path, but it does not name the specific sibling tool, so the exclusion is slightly less direct than ideal.

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