MCP Basics

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 command but doesn't explain that this is a write operation (modifies files), potential side effects (overwrites existing formatting), permissions needed, or execution time. This is a significant gap for a tool that alters files.

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 extremely concise—a single sentence that directly states the tool's action and command. It's front-loaded with the essential information, with no wasted words or unnecessary elaboration.

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 (executes a command that modifies files) and lack of annotations or output schema, the description is incomplete. It doesn't cover behavioral aspects like file changes, error handling, or output format, which are critical for safe and effective use by an AI 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 100% description coverage, with one optional parameter ('directory') clearly documented. The description adds no parameter information beyond what the schema provides, so it meets the baseline of 3 for high schema coverage without compensating value.

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 ('Execute mcp-formatter') and the specific command to run ('npx prettier --write .'), which indicates it formats code using Prettier. However, it doesn't explicitly differentiate from sibling tools like mcp-linter or mcp-docs, which might also involve code processing.

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 scenarios like code formatting before commits, after editing, or in CI/CD pipelines, nor does it reference sibling tools for comparison, leaving the agent to infer usage context.

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