VOICEVOX TTS MCP

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool retrieves a list, implying a read-only operation, but doesn't cover aspects like whether it requires authentication, has rate limits, returns paginated results, or what format the list is in. For a tool with zero annotation coverage, this is a significant gap in transparency.

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?

The description is a single, efficient sentence ('Get a list of available speakers') that is front-loaded and wastes no words. It directly states the tool's purpose without unnecessary elaboration, making it highly concise and well-structured for its simplicity.

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?

Given the tool's complexity (simple list retrieval) but lack of annotations and output schema, the description is incomplete. It doesn't explain what the list contains, how it's formatted, or any behavioral traits. For a tool with no structured data beyond the input schema, more context is needed to be fully helpful to 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?

The input schema has 0 parameters with 100% coverage, so the schema fully documents the lack of inputs. The description doesn't add parameter details beyond this, which is appropriate. Since there are no parameters, the baseline is 4, as the description doesn't need to compensate for any gaps.

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 states the tool's purpose ('Get a list of available speakers'), which is clear but vague. It specifies the verb ('Get') and resource ('speakers'), but doesn't distinguish it from sibling tools like 'get_speaker_detail' or explain what 'available' means in this context. This is adequate but has clear gaps in specificity.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention sibling tools like 'get_speaker_detail' for detailed information or 'synthesize_file' for synthesis operations, nor does it specify prerequisites or contexts for usage. This leaves the agent without explicit or implied usage instructions.

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