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

With no annotations, the description must carry the behavior burden. It does disclose real traits: zero API key or auth required, no cost, and that the result is a playable 22.05kHz PCM WAV rather than a stream or prompt. It omits latency, whether output is a URL/base64/file handle, clip duration, and whether calls are idempotent.

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 tight clauses: a bracketed cost/auth hook followed by one sentence naming the action and artifact. Every element earns its place and the differentiator (

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 one-parameter enum tool with no output schema, the description usefully covers the return artifact type, which is the main missing piece otherwise. However, it leaves unclear how the WAV is delivered (URL, inline audio, file), how long the clip is, and whether the same sfxId always yields identical audio.

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 already carries an enum plus a description ('Built-in procedural sound effect ID'). The description adds only a light distinction between 'sound effect' and 'beat loop' as output categories; it does not explain what each enum value sounds like or how to choose between them.

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 ('Synthesize'), a specific resource ('sound effect or beat loop'), and the output format ('playable 22.05kHz PCM WAV'), which is enough to separate it from siblings like fahi_generate_image or fahi_generate_bangla_tts. It does not explicitly name a sibling or contrast itself with one, which keeps it out of the top band.

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 only implied: an agent can infer 'call this when a short SFX or beat loop is needed for a CapCut studio workflow.' There is no explicit when-to-use statement, no when-not-to-use, and no named alternative for musical or longer-form audio needs.

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