Underground Cultural District MCP Server

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 only states what the tool does ('URL-encode or URL-decode a string') without detailing behavioral traits such as error handling (e.g., for invalid input), performance characteristics, or side effects. This is inadequate for a tool with no annotation coverage.

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 and front-loaded: 'URL-encode or URL-decode a string.' It uses minimal words to convey the core functionality without any wasted sentences, 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 (2 parameters, no output schema, no annotations), the description is incomplete. It lacks details on output format (e.g., what the encoded/decoded string looks like), error cases, or practical examples. For a tool with moderate parameter coverage and no annotations, more context is needed to be fully helpful.

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 no parameter semantics beyond what the input schema provides. With 50% schema description coverage (only 'text' has a description, 'mode' does not), the description does not compensate by explaining the 'mode' parameter's 'encode'/'decode' options or their effects. Since schema coverage is moderate, the baseline score of 3 applies, as the description does not enhance parameter understanding.

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: 'URL-encode or URL-decode a string.' It specifies the verb ('encode'/'decode') and resource ('string'), but does not distinguish it from sibling tools like 'encode-base64' or 'decode-base64', which perform similar encoding/decoding operations on different formats. This lack of sibling differentiation prevents a score of 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. It does not mention sibling tools like 'encode-base64' for different encoding needs or clarify scenarios for URL encoding/decoding (e.g., handling URLs in web requests). Without any context or exclusions, it offers minimal usage direction.

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