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

Adds behavior the annotations do not carry: it is free (no credits), it writes the take into the user's library, and the losing take is discarded. The discard side effect is the one borderline point against destructiveHint=false, but the tool's target resource is being preserved, not destroyed, so this reads as transparent rather than contradictory. It does not say whether the discard is reversible or what is returned.

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 no waste, ordered from what the tool does to when to use it to the downstream dependency. The prerequisite is placed last where it is most likely to be acted on.

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 single-parameter mutation with no output schema, it covers cost, side effects, and downstream dependency, which is most of what an agent needs. The remaining gap is what the call returns and whether a kept take can be swapped later.

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 parameter description already says track_id comes from get_job. The description only adds that the id is the take the person chose, which is context rather than format or constraint detail, so 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?

States a specific verb and outcome: choose one of two takes, save it to the library as the song, discard the other. The two-take framing makes it unmistakable against siblings like create_song or edit_song.

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?

Gives the trigger ('after the person has heard both') and an explicit prerequisite naming a sibling: 'A take must be kept before make_music_video can use it.' An agent knows both when to call it and why a downstream tool would fail without it.

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