url_decode

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 clearly describes the non-destructive decode operation and references decodeURIComponent, indicating expected behavior. However, it does not address edge cases like invalid encoding or non-encoded input.

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?

Two sentences, zero waste. The core action is front-loaded, and the additional sentence provides usage context. Every word earns its place.

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 tool with one parameter and no output schema, the description completely covers the purpose, usage, and expected behavior. No additional information is needed for an agent to select and invoke the tool correctly.

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 coverage is 100% (the single parameter 'text' is described). The description adds conceptual context that the input is percent-encoded and output is plain text, but this largely overlaps with the schema description. The baseline of 3 is appropriate given full schema coverage.

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 the resource 'percent-encoded URL string', and explicitly distinguishes it from url_encode by mentioning decodeURIComponent. It tells the agent exactly what the tool does and how it differs from the sibling url_encode.

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 states when to use it ('Use to recover the original text from a URL-encoded value'), providing clear context. However, it does not explicitly provide when-not-to-use guidance or compare with other decoding tools like base64_decode, which are available as siblings.

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