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

Annotations cover the read-only and open-world profile, and the description goes further by disclosing per-call cost ($0.012 USDC, x402 payment) and the default output codec — real behavioral facts not in the schema. It omits the 20 MB input ceiling and the paid-store upsell, but the cost disclosure is the high-value addition here.

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?

Two tight sentences with no filler: the action and format list come first, the cost caveat second. Every clause earns its place.

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?

Adequate but with a real gap: with 9 parameters and 0 required, the agent must infer that either url or file_base64 is needed, and the description never clarifies that input-source choice. Return-shape questions (base64 vs share links) are only covered in the schema's 'store' parameter, and sample_rate/channels/audio_bitrate are left unexplained.

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 78%, so the schema already documents most inputs (including the default mp3 in the 'to' parameter). The description mostly restates those formats and adds no syntax, mutual-exclusivity or defaulting detail beyond what the schema provides; baseline 3 applies.

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 ('pull the audio track out of a video') plus the set of output formats, so it is clearly an audio-extraction tool rather than a general converter. It never names a sibling (e.g. media_convert, media_trim, transcribe), so the differentiation is implicit rather than explicit.

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?

'ready for transcription or editing' implies the downstream use case, and the pricing line hints this is a paid, on-demand call. There is no explicit when-to-use/when-not-to-use guidance or pointer to alternatives such as media_convert for non-audio conversions.

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