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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds non-obvious context beyond that: it returns the clip's size and 'never the audio,' and clarifies the downstream wiring. No permissions or failure modes are mentioned, but with annotations carrying the safety burden this is solid.

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?

Three tight sentences, front-loaded with the core action and precondition, followed by the return clarification and downstream usage. Zero filler; every clause carries 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?

Output schema exists so return values needn't be spelled out, and annotations cover the safety profile. The description completes the picture with the upload sequence and the consumer of upload_id, leaving nothing an agent needs to call it 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 coverage is 100%, so both parameters are already documented (upload_id's origin and workflow_id's optional attachment). The description adds meaning beyond the schema by explaining what upload_id is ultimately for (source_audio node line, language, script), which the schema does not.

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 ('Register') and resource ('an audio clip') with the precondition that distinguishes it from its sibling: 'whose bytes you already PUT to an upload_url.' An agent can tell this is the second step after upload_audio_file without opening either 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?

Clearly places the tool in the upload sequence (bytes already PUT) and tells the agent what to do with the result: pass upload_id to a source_audio node line with language and script. It stops short of explicitly naming upload_audio_file as the prerequisite, so the sequencing is inferred rather than stated.

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