YouTube to audio (MP3, M4A, WAV, FLAC...)

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

Goes well beyond the annotations (readOnlyHint=false, idempotentHint=true, openWorldHint=true) by disclosing the ~2 minute wait ceiling, the jobId fallback path, the ~30 minute link expiry, and the unsupported source classes. These are exactly the operational traits an agent needs to sequence a download.

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?

Front-loaded with purpose, then formats, clipping, return values, timing behavior, and exclusions in a logical order. Slightly dense with one sentence repeating the schema's enum lists, but nearly every clause carries actionable information.

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?

With no output schema, the description carries the return-value burden and does so (link, fileName, fileSize, durationSeconds), plus timeout, expiry and source-limit behavior. Nothing an agent needs to invoke and then download the result 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?

Schema coverage is 100% with documented enums, so the schema already carries parameter meaning; the description largely restates the format/bitrate enumerations and the startTime/endTime clipping that are already in the schema. It adds little syntax or constraint detail beyond what is structured, so the 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+resource+output (convert a public YouTube video/Shorts URL to an audio file) and immediately distinguishes itself from youtube_transcript and get_job by naming the download-link return. An agent can identify the tool's job without opening the schema.

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 conditions for use and explicit exclusions: private, removed, age-restricted and live videos are not supported, and sources are capped at 3 hours. It also routes the agent to get_job when the wait times out. It does not, however, contrast this tool against the sibling youtube_transcript (audio vs. text), which is the main missing routing cue.

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