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

With annotations already covering the safety profile (non-read-only, non-destructive, non-idempotent, closed-world), the description adds real value: credits are held on acceptance and refunded on failure/cancellation, the result is a single audio asset whose extension reveals MP3 vs WAV, and the call is async returning {id, status} that must be polled via getApiJob. It slightly under-describes the request_id dedup behavior (re-sending the same idempotency key returns the existing job) that the schema states, which is why it doesn't reach 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 the core action and examples, then constraints, then sibling routing, then the async/credit contract — a sensible order with nearly every sentence earning its place. It runs long for one tool, and the separated "Credits: This endpoint consumes 2 credits per call" line partially duplicates the earlier credit-hold sentence.

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 an async, credit-consuming generation job with a nested request body and no output schema, it covers everything an agent needs: what is produced (single audio URL), required input, duration bounds, looping, idempotency tagging, cost, and how to retrieve the result via getApiJob/listGenerations. Nothing material 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 description coverage is 100% and every parameter (description, duration, loop, request_id, augment_prompt) is already documented in-schema with ranges and defaults. The description restates the headline constraints (required description, 10s cap, 0 = auto, loop for seamless looping, request_id as a tag), which is convenient but adds no semantics the schema lacks. Baseline 3 applies when the schema carries the weight.

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 concrete verb and resource ("Produce a short sound effect (SFX) from a text description") with two illustrative examples that remove ambiguity about the input. It explicitly positions itself against four siblings (createAmbiance, createMusic, createAudioTransform, listGenerations), so an agent can distinguish it without opening any 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?

Gives an explicit routing rule: "Use this for short, discrete sounds; use createAmbiance for a continuous looping background soundscape, createMusic for musical pieces, and createAudioTransform to remix an existing audio sample." It also names the follow-up call (getApiJob polling, listGenerations with type audio) and the credit condition, leaving nothing to inference.

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