fang_url

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

The description indicates that the tool performs a mutation (defang or refang), consistent with annotations (readOnlyHint=false). However, it adds no extra behavioral context beyond the basic operation, such as side effects, required permissions, or output format.

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 sentence that is front-loaded with the key verbs and resource. It is concise and contains no unnecessary words.

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 low complexity (2 parameters, no nested objects, no output schema), the description is adequate but lacks information about the return value or potential errors. For a complete understanding, mentioning that the tool returns the processed text would be beneficial.

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% coverage with descriptions for both parameters (text and operation). The tool description does not add any new information about the parameters beyond what the schema already provides, so 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 that the tool defangs or refangs URLs for safe sharing in security analysis. It uses specific verbs and a specific resource (URLs), distinguishing it from general URL encoding/decoding tools like decode_url or encode_url.

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 for safe sharing in security contexts but provides no explicit guidance on when to use this tool versus alternatives such as decode_url or encode_url. No when-not-to-use or conditional advice is given.

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