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

Annotations already establish readOnlyHint=true, so the safety profile is covered, but the description adds genuinely useful behavior: polling is free, the MP3 plus link is returned only on success, and failed jobs refund themselves. That billing and terminal-state behavior is not derivable from annotations or schema. Minor ambiguity remains around 'Free' vs. self-refunding failures.

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 short sentences with zero filler; the core action, the cost note, and the outcome states are front-loaded in that order. 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?

With no output schema, the description correctly carries the return-value burden by stating that the MP3 and its link come back on success. The main omission is timing behavior (poll cadence, expected latency, link expiry) for an inherently async status tool, but nothing essential for calling it correctly is missing.

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% and the single parameter is fully documented in the schema as 'the job id returned by generate_music'. The description only echoes 'by id', adding no format, sourcing, or lifecycle detail beyond what the schema already provides, so the baseline 3 applies.

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 names a specific verb and resource ('Poll a song job by id'), and the required 'id' is tied back to generate_music in the schema, which lets an agent place it correctly in the async generate-then-poll workflow. It doesn't explicitly contrast itself with the parallel get_image_status/get_video_status siblings, but the scope is unambiguous.

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?

Usage is implied rather than stated: 'Poll a song job by id' suggests calling after generate_music and repeating until completion, but the description never says to poll repeatedly, how long to wait, or that this is the only way to retrieve the result. No explicit when-not or alternative is given.

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