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

Annotations only declare the safety profile (not read-only, open-world, non-destructive), so the description carries real weight here and does add value: it discloses async execution, the returned task_id, and a credit cost, none of which the annotations cover. It still omits failure behavior, polling expectations, and where the rendered file lands relative to 'out'.

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?

Two sentences, zero filler, and the key facts (what it produces, the model, async, return shape) are front-loaded. Nothing is redundant with the schema or annotations.

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 5-parameter, credit-consuming async generation tool with no output schema, the description covers the return payload at a high level but leaves the async lifecycle unexplained – no pointer to composer_task_status, no note on failure/refund behavior, and no statement of where the artifact is written.

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% – prompt, out, seed, duration and project_id are all documented in-schema, including the seed dedupe window and Lyria's duration overshoot behavior. The description adds no parameter meaning whatsoever, 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?

States a specific verb and resource ('Generates a music track'), names the underlying model (Lyria 3 Pro), and flags the async execution mode. It does not explicitly distinguish itself from the closest siblings (composer_generate_clip, composer_voice_line), so it stops short of a 5.

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?

There is no when-to-use guidance at all: nothing says when to pick this over composer_generate_clip or composer_voice_line, and no prerequisites are stated beyond the schema's reference to composer_project_create. The async note implies a follow-up poll but never names composer_task_status.

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