mcp-server-devutils

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 action ('decode') but doesn't describe error handling (e.g., for invalid Base64), output format (e.g., string vs. binary), or performance characteristics. This leaves significant gaps for a tool that transforms data.

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 with zero waste. It is front-loaded with the core action and resource, making it easy to parse. Every word earns its place, and no unnecessary details are included.

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 lack of annotations and output schema, the description is incomplete. It doesn't explain what the tool returns (e.g., decoded text, potential errors), which is critical for a decoding operation. For a tool with 100% schema coverage but no behavioral context, this leaves the agent guessing about outcomes.

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?

Schema description coverage is 100%, with the parameter 'input' clearly documented as 'The Base64 string to decode'. The description adds no additional meaning beyond this, such as format requirements or examples. Since the schema does the heavy lifting, the baseline score of 3 is appropriate.

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 verb ('decode') and resource ('a Base64 string'), making the purpose immediately understandable. It distinguishes from its sibling 'base64_encode' by specifying the opposite operation. However, it doesn't explicitly mention what the output is (decoded text/binary), which prevents a perfect score.

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 where Base64 decoding is appropriate, prerequisites for the input string, or comparisons with other tools like 'jwt_decode' that might also handle encoded data. The agent must infer usage from the name alone.

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