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

No annotations are supplied, so the description carries the full burden. It does disclose the key behavioral trait that outputs may not cover the whole input, and that duration_ms and transcript boundaries should be respected - valuable context about silent truncation. It does not state whether the call is side-effect free, whether limits are per-account or per-key, or caching behavior.

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 lines, front-loaded with the purpose before the caution. The second and third sentences both address the same concern (incomplete processing of long inputs), so there is minor overlap, but no wasted framing or 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?

An output schema exists, so return values need not be explained, and with no parameters there is little surface to cover. The description supplies purpose, call timing, and the one trap an agent could fall into (assuming full transcription). Only a note on limit scope or failure modes is missing.

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?

The tool takes zero parameters, so the description has nothing to disambiguate and the baseline is 4. The schema is empty and fully described; no parameter meaning is lost.

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: retrieve the caller's audio/video duration limits and long-form eligibility. This is clearly distinguishable from the transcription, synthesis and translation siblings. 'Capabilities' is a slightly broad container term, but the sentence immediately qualifies it with concrete contents.

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 explicit timing guidance: 'Check before transcription', and a precondition-style warning not to assume a long input was processed fully. It does not name a specific alternative tool to call instead, but the usage context is unambiguous for the pre-transcription step.

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