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

Despite the annotations only covering the safety profile, the description discloses the full lifecycle: the server downloads the file, stores it in Cloudflare R2 while the job runs, processes it via a headless browser, deletes the input when done, and returns download links that expire after 1 hour. This is exactly the kind of post-annotations context that helps an agent reason about a non-idempotent, non-read-only tool.

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?

Purpose is front-loaded in the first sentence and the rest is organized as input, options, return value, then backend behavior. The infrastructure sentence is longer than strictly needed, but each clause (storage location, processing, input deletion) carries behavioral weight rather than 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?

With no output schema, the description correctly compensates by describing the return (expiring download links), and it covers the async job lifecycle. The only genuine gap is the opaque `settings`/mode parameter, whose valid values remain undisclosed in both schema and description.

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% for the top-level params, so the baseline is 3. The description attempts to clarify the otherwise empty `settings` object ('set_channel_mode: mode') but does not enumerate allowed mode values, and merely echoes outputFormat/bitrateKbps already documented in the schema.

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 opening sentence gives a specific transform ('converts between stereo and mono, or keeps one channel'), which is clearly distinct from siblings like stereo_widener or audio_converter. It states the resource and the operation without ambiguity, though it never explicitly names a sibling to steer the agent.

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 implies usage by stating the input requirement (one file with a public HTTPS download_url) and the optional mode/format settings, but it never says when to pick this over stereo_widener or audio_converter, nor any exclusion or prerequisite conditions. Usage is inferable, not stated.

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