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

Annotations already declare destructiveHint=true, openWorldHint=true, and non-idempotence, so the safety profile is largely covered. The description adds genuine context beyond them: it consumes the account plan quota exactly like a direct API call, and it cannot accept binary file uploads (audio must be a URL). It does not spell out which calls are destructive or how errors/rejections surface, keeping it short of a 5.

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 what the tool is and what it costs, then the alternative-tool guidance, then prerequisites, then a hard limitation. It is dense but every sentence carries operational information; the mid-sentence em-dash list and slightly long quota/preference clause keep it from a perfect 5.

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?

For a generic pass-through API tool with an output schema available, the description covers the essentials an agent would otherwise guess wrong: authentication context ('as this account'), quota consumption, the preferred alternative path, the docs prerequisite, and the no-file-upload constraint. Nothing critical is left unstated.

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%, so path and params are already documented in the schema, including the api_token injection note. The description adds only the constraint that audio must arrive via a URL-style param (e.g. params.url) rather than a file upload, which is useful but marginal over the structured fields; baseline 3 is appropriate.

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 description opens with a concrete verb plus resource ('Calls the AudD API (api.audd.io) as this account') and enumerates the capability surface (music recognition, streams management, callbacks). It also names the sibling tools it relates to (get_api_token, get_api_docs), so an agent can place it against 19 alternatives without opening a 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?

Explicit routing guidance: prefer get_api_token for repeated or programmatic use and call the API directly, and reserve make_api_request for one-off or interactive calls. It also states a prerequisite ('Read get_api_docs first for endpoints and parameters'), which is exactly the when-to-use info an agent needs.

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