VOICEVOX TTS MCP

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the tool checks if the engine is 'running and reachable,' implying a read-only, non-destructive operation, but doesn't detail what happens on failure (e.g., error responses), latency, or any side effects. For a tool with zero annotation coverage, this leaves gaps in understanding its behavior.

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: 'Check if VOICEVOX Engine is running and reachable.' It is front-loaded with the core purpose, has no wasted words, and is appropriately sized for a simple tool. Every part of the sentence earns its place by conveying essential information.

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 low complexity (0 parameters, no output schema, no annotations), the description is minimally adequate. It states what the tool does but lacks details on usage context, error handling, or return values. Without an output schema, it doesn't explain what 'check' returns (e.g., status, boolean), leaving some gaps for an agent to understand fully.

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 tool has 0 parameters, and the input schema has 100% description coverage (though empty). The description doesn't need to explain parameters, so it naturally adds no value beyond the schema. A baseline score of 4 is appropriate for zero-parameter tools, as there's no parameter information to compensate for.

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's purpose: 'Check if VOICEVOX Engine is running and reachable.' It uses a specific verb ('Check') and identifies the target resource ('VOICEVOX Engine'), making it easy to understand. However, it doesn't explicitly differentiate from sibling tools like 'get_speakers' or 'synthesize_file', which serve different purposes but also interact with VOICEVOX.

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 (e.g., before using other tools), exclusions, or contextual cues. For example, it doesn't specify if this should be called first to verify connectivity before invoking 'speak' or 'synthesize_file'.

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