MCP Server Framework

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

No annotations are provided, so the description carries the full burden. It states the tool echoes back the message and confirms receipt, which implies a read-only, non-destructive operation. However, it lacks details on error handling, rate limits, authentication needs, or any side effects, leaving behavioral gaps for a tool with no annotation support.

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 well-structured and front-loaded with the core purpose, followed by clear sections for Args and Returns. Every sentence earns its place, with no wasted words, making it efficient and easy to parse.

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 simplicity (one parameter, no annotations, but with an output schema), the description is reasonably complete. It explains the purpose, parameter, and return value. The output schema likely covers return details, so the description doesn't need to elaborate further. However, it could improve by addressing sibling differentiation or behavioral nuances.

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 description adds meaningful context beyond the input schema. With 0% schema description coverage, the schema only defines 'message' as a required string. The description clarifies that this is 'The message to echo back,' providing semantic intent. Since there's only one parameter, this is sufficient, though not exhaustive (e.g., no format constraints).

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: 'Echo back the provided message.' This is a specific verb ('echo back') with a clear resource ('the provided message'), making the function obvious. However, it doesn't explicitly differentiate from siblings like echo_reverse or echo_uppercase, which would require a 5.

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. With siblings like echo_reverse and echo_uppercase available, there's no indication of when this simple echo is preferred over those modified versions, nor any context about prerequisites or exclusions.

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