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

Goes well beyond the readOnlyHint/openWorldHint annotations with concrete economics ($0.002 + $0.07/1k chars, $0.005 min, $0.06 USDC per call via x402) and the store=true side effect of returning a 7-day share link instead of inline bytes. It omits rate limits and failure modes, so it is rich but not exhaustive.

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 dense sentences, each earning its place: capability, then output format, then the store tradeoff and price. Front-loaded with the distinguishing engine name and effect. Pricing detail is heavy but decision-relevant for a paid tool.

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 and only two annotations, the description carries the load well by specifying return format (MP3 or base64 JSON), the share-link alternative, and full cost structure. Missing only rate limits, error behavior, and explicit sibling routing to be complete.

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%, so all five parameters are already documented, and the description largely restates them (voice examples, mp3/json, en/es). The only added meaning is the cost consequence of store=true, which the schema already notes as (+$0.001).

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+resource ('natural speech' synthesis) and pins the engine (Deepgram Aura-2) plus voice/language coverage, which is far more concrete than a bare 'text to speech'. It implies a premium tier versus the sibling 'speak', but never names the alternative, so an agent can't fully rank speak_pro against speak/audio_speech from text alone.

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?

No when-to-use or when-not guidance is given despite three plausible siblings (speak, audio_speech, voice_session). The pricing and x402 cost data give an implicit 'use sparingly' signal, but the agent is left to infer that 'speak' is the cheaper path.

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