url_encode

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

With no annotations available, anyway fthe description carries the burden. It discloses that the tool can both encode and decode based on what is 'asked', which is useful beyond the name. It also mentions the resource type (URL string) directly; however, it does not detail the return format. The core behavior is fully.

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 well-packed sentence with a clarifying parenthetical. There is no filler or repetition of schema names, and it front-loads the main purpose.

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 encode/decode utility with only two primitive parameters and an obvious string output, the description is nearly complete. It does not spell out the exact return value, but that is inferable from 'percent-encode'. Its main gap is lacking guidance on edge cases or alternate tool choice.

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 schema has 0% description coverage, so the description must fill gaps. It does add 'URL string' for the text parameter and implies the decode via mode, but it doesn't explicitly map the two parameters or explain control values for `mode`. This is partial compensation for the missing schema-property descriptions.

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 says clearly what the tool does: percent-encode a URL string, and it mentions the decoding capability in a parenthetical. This is a specific action on a specific resource and is clearly different from the sibling tools like base64_encode/base64_decode, which are base64 operations rather than URL percent-encoding.

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 gives implied guidance: use this when you need to percent-encode or decode a URL string. However, it does not explicitly tell the agent when not to use it or point to alternative tools, such as base64_encode/decode for base64 encoding, so exclusions are missing.

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