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

Annotations only give the generic safety flags (readOnlyHint=false, idempotentHint=false), while the description adds genuinely non-obvious behavior: credits are charged per second of media and measured by the server. The async pattern is partly covered by the wait_seconds schema, so this is a strong but not exhaustive disclosure.

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?

One tight passage, front-loaded with what the tool does and its output, then cost and parameter pointers. No filler sentences.

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?

No output schema exists, but the description compensates by naming the return value (timestamped SRT) and the billing model. It could mention what happens on failure or how get_job_status ties in, but an agent has enough to call it 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 only adds that language must come from list_languages, which is mildly useful but mostly redundant with the schema's 'Spoken language code' text and the create_upload_url reference for media_url.

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 ('Speech-to-text for an uploaded video or audio file') plus the concrete output ('timestamped SRT'), and names the downstream sibling srt_to_speech so the agent can distinguish its role. Nothing ambiguous.

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?

Gives clear positive guidance: use language codes from list_languages, and the SRT feeds srt_to_speech for rewrite/translate/re-voice. It stops short of explicit exclusions versus siblings like get_transcription or localize_video, so a 4 rather than 5.

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