MCP Server Framework

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

With no annotations provided, the description carries full burden. It clearly describes the core behavior (reversing characters), but doesn't disclose additional traits like error handling, performance characteristics, or side effects. The description is accurate but minimal.

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 perfectly structured with a clear purpose statement followed by Args and Returns sections. Every sentence earns its place - no wasted words, front-loaded with the core functionality.

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 simple single-parameter transformation tool with an output schema, the description is reasonably complete. It explains what the tool does, the parameter meaning, and the return value. However, it could benefit from more behavioral context given the lack of annotations.

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 0% schema description coverage and only 1 parameter, the description compensates well by clearly explaining the 'message' parameter's purpose ('The message to reverse') and the return value semantics, adding meaningful context beyond the bare schema.

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 explicitly states 'Echo back the message reversed' - a specific verb ('echo back') and resource ('message reversed'), clearly distinguishing it from siblings like 'echo' and 'echo_uppercase' by specifying the reversal operation.

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 implies usage context through the tool name and description, suggesting it's for reversing text messages, but provides no explicit guidance on when to use this versus alternatives like 'echo' or 'echo_uppercase', nor any prerequisites or exclusions.

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