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

Annotations already declare readOnlyHint=true, and the description adds valuable behavioral detail: it runs locally, returns the encoded string, and follows encodeURIComponent rules. No hidden side effects or network calls are implied. This exceeds the baseline given the annotations.

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 efficient sentences with no filler. The core purpose is front-loaded, and the encoding details and local-execution note both earn their 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 single-parameter, read-only tool with no output schema, the description fully covers what the agent needs: what input to provide, what encoding rules apply, where the result is used, and what the tool returns.

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%, so the parameter is already documented. The description adds useful semantic context by specifying the encoding rules and the URL contexts where this encoding applies, going beyond the schema's simple 'Text to encode.'

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?

States a specific verb ('Percent-encode') and a clear resource (text for URL query values or path segments), and specifies the exact encoding rule (encodeURIComponent). This clearly distinguishes it from sibling tools like url_decode and base64_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 explains when to use it: when percent-encoding text for URL query values or path segments. It also notes that it runs locally, implicitly distinguishing it from network-dependent tools. It does not explicitly name alternatives or exclusions, but the use case is clear enough.

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