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

Annotations only declare the generic mutation profile (readOnlyHint=false, destructiveHint=false), so the description carries the behavioral load and does it well: result links expire after 1 hour, the file is downloaded server-side, held in Cloudflare R2 only while the job runs, processed via a headless browser, and the input is deleted when the job ends. This lifecycle and retention detail is exactly the context annotations cannot supply.

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, followed by input, parameters, output, and processing pipeline in a logical order. Slightly long, with infrastructure detail (R2, headless browser, Cloudflare) that borders on excess, but nothing is genuinely wasted.

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, so the description correctly states the return value (download links, expiring after 1 hour) and also covers input requirements, optional parameters, and data-retention behavior. For a file-in/link-out processing tool this is complete enough to invoke 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 largely restates the schema ('settings for set_stereo_width: width', outputFormat examples mp3/wav/m4a), adding only the minor caveat 'where the tool supports them'; for the free-form settings object it offers no value range or units for width.

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: 'Widens or narrows the stereo image.' An agent can distinguish this from adjacent siblings like stereo_to_mono by function, but the description never names or contrasts a sibling, so full sibling differentiation is left to inference.

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?

There is no when-to-use, when-not-to-use, or alternative-tool guidance. The description only documents inputs and lifecycle; nothing tells the agent when to pick this over stereo_to_mono or equalizer.

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