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

No annotations are provided, so the description carries the behavioral burden. It correctly conveys that this is a reversible text transformation, but says nothing about behavior on malformed input during decode (e.g., invalid percent sequences) or the exact return shape. For a low-risk pure utility function this is thin but not dangerous.

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?

A single short clause, front-loaded with the operation and the resource, with zero filler. Nothing can be trimmed without losing meaning.

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 two-parameter, fully documented utility with no output schema, the description is nearly sufficient. It still omits what decode does with malformed input and what exactly is returned, which are the only remaining ambiguities an agent would face.

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%, including the enum for mode and its 'default encode' note, so the schema already documents both parameters. The description only restates the mode values and adds no semantics about text (e.g., encoding expectations) beyond what is already structured data.

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 names the exact operation ('percent-encode/decode') and the resource ('text'), which implicitly distinguishes it from siblings like base64 and slug that also transform strings. It stops short of explicitly naming an alternative, but the encoding scheme is specific enough that an agent can pick this tool over base64/hash without opening the schema.

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 'mode=encode|decode' clause hints at the two operating modes, so usage is implied rather than stated. There is no guidance on when to choose this over base64 or slug encoding, and no noted prerequisites or exclusions.

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