Speak

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

With no annotations provided, the description carries the full burden, and it makes a reasonable effort. It discloses the side effect of audio playback ('play it on the user's machine') and thoroughly documents the voice resolution fallback order (TTS_VOICE env var, voices/default*, first file in voices/, then af_heart). However, it doesn't disclose potential blocking behavior, absence of audio hardware, or other side effects that could be expected given the nature of the tool.

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?

Four sentences, with the core purpose front-loaded first and the resolution detail last. Every sentence earns its place — the usage guidance and voice resolution order are both essential for the agent. The voice resolution sentence is dense but packs critical behavioral information. A slight trim could occur since the resolution order could be seen as implementation detail.

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?

The description captures the core essence—synth and play, when to trigger, how voice is resolved—which is solid for a 3-parameter tool. No annotations or schema descriptions exist to offload this burden to. Missing context includes behavior of the speed parameter, the relationship to the sibling list_voices, and failure modes. Given the total absence of annotations and schema descriptions, the description could do more to guide an agent.

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?

With 0% schema description coverage, the description needed to compensate, and it partially does. It adds value for the text parameter ('clear, natural text to speak') and implicitly for the voice parameter by explaining the resolution order. However, the speed parameter is entirely unexplained (what units, what range), and the voice format is only hinted at. Given the extremely low schema coverage, this partial compensation keeps it at a decent but not exceptional level.

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?

The description opens with a specific verb and resource ('Synthesize speech with Kokoro-82M and play it on the user's machine') that clearly identifies what the tool does. It goes further to elaborate intended use cases ('when the user wants the harness to talk, read something aloud, or hear a spoken response'). It doesn't explicitly contrast itself with the sibling list_voices, which keeps it just 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?

The description gives explicit when-to-use guidance with concrete examples ('when the user wants the harness to talk, read something aloud, or hear a spoken response'). It includes a practical instruction to 'Always pass clear, natural text to speak.' However, it stops short of explicitly naming alternatives (e.g., list_voices) for comparison or stating when not to use it, so it lacks the explicit exclusions of a perfect score.

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