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

Annotations already flag non-readonly, non-idempotent behavior, but the description adds substantial operational context: server-side download, temporary R2 storage during the job, headless-browser processing, deletion of the input at job end, and 1-hour expiry of result links.

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-loads the core purpose, then covers input, optional options, output lifetime, and backend handling. The backend storage/processing details are longer than typical but relevant for trust and privacy; no sentence feels purely wasteful.

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, and the description explains the return (download links expiring after 1 hour). For a non-idempotent processing tool, it discloses input handling, storage, deletion, and output lifetime, leaving no critical gap for correct invocation.

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 parameters are already well documented. The description restates the required file/download_url and optional outputFormat/bitrateKbps, adding only the caveat that formats/bitrates are supported 'where the tool supports them' without enumerating supported values.

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 the specific transformation ('Reverses audio so it plays from end to start') with a clear verb and resource. In a large sibling set of audio processors, this unique effect is immediately distinguishable from alternatives.

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?

Specifies the input prerequisite (one file with a public HTTPS download_url) and optional parameters, giving clear context for invocation. It does not name alternative siblings or state when not to use this tool, but the transformation is distinct enough that exclusions are less critical.

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