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 mentions generating a file and returning a path, but lacks details on permissions, side effects (e.g., file system changes), rate limits, error handling, or audio format specifics. This is inadequate for a tool that creates files, as it doesn't clarify behavioral traits beyond the basic operation.

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 that front-loads the core action and return value. Every word earns its place, with no redundancy or unnecessary elaboration, making it easy to parse quickly.

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 complexity of a file-generation tool with 5 parameters, no annotations, and no output schema, the description is incomplete. It doesn't cover behavioral aspects like side effects, error cases, or audio specifics, and lacks usage context. This leaves significant gaps for an AI agent to understand how to invoke it correctly in various scenarios.

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 the schema already documents all parameters thoroughly (e.g., precedence rules for text vs. query, optional defaults). The description adds no additional parameter semantics beyond what the schema provides, such as explaining the audio generation process or file format details. Baseline 3 is appropriate when the schema does the heavy lifting.

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 clearly states the action ('Generate an audio file') and the resource ('audio file'), and specifies the return value ('return its absolute path'). It distinguishes from siblings like 'speak' (which might stream audio) and 'generate_query' (which likely creates queries rather than files). However, it doesn't explicitly differentiate from all siblings (e.g., 'stop_speaker' is clearly different).

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 guidance is provided on when to use this tool versus alternatives. The description doesn't mention prerequisites, context, or comparisons to siblings like 'speak' (which might be for immediate playback) or 'generate_query' (which might be for query generation without file creation).

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