VOICEVOX MCP Server

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

With no annotations provided, the description carries the full burden and successfully discloses the asynchronous execution model and audio playback side effect. However, it omits queue behavior, error handling, and whether the operation is destructive or 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?

The single-sentence description is tightly focused, front-loaded with the core action (VOICEVOX synthesis), and contains no redundant information. Every element (engine, action, execution mode) earns its place.

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 4-parameter tool with simple types, the description covers the primary function and async nature adequately. However, given the absence of an output schema, it should ideally describe return values (e.g., success confirmation, job ID) or queue interaction effects.

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 100% schema description coverage, the schema adequately documents all parameters. The description does not add parameter-specific semantics beyond what's in the schema, meeting the baseline for high-coverage schemas.

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 tool performs speech synthesis (音声合成) and playback (再生) using the specific VOICEVOX engine, distinguishing it from sibling tools that only query voice metadata or manage queues.

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?

While '非同期実行' (asynchronous execution) implies non-blocking usage, the description lacks explicit guidance on when to use this versus alternatives like get_session_voice or how it interacts with the queue system suggested by sibling tools.

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