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

With no annotations, the description carries the full burden. It usefully discloses the encoding algorithm (encodeURIComponent rules) and the cost ($0.01/call, USDC on eip155:8453), but says nothing about return format, handling of malformed percent sequences on decode, or error behavior.

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?

Three sentences, front-loaded with the core action, with no padding. The pricing sentence is arguably relevant for an autonomous agent but the malformed 'needs to percent-encoding' phrase hurts readability.

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 stateless two-parameter text transform with no output schema, the description covers what the tool does, the encoding standard, and cost. Output shape is self-evident for a converter, so little is missing.

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%, but the field descriptions are near-useless ('Direction', 'Text'). The description clarifies that the two directions are encode and decode and pins the encoding scheme to encodeURIComponent, adding some meaning over the enum alone; baseline 3 applies when the schema handles the rest.

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 and resource ('percent-encode text for URLs and query strings, or decode percent-encoded text back'), so the operation is unambiguous. It does not name or differentiate against close siblings like dev_url_parser or dev_base64_encode, so it falls short of a 5.

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?

'Use this when an agent needs to percent-encoding for query strings and URLs' gives a usage condition, but it is grammatically garbled and largely restates the purpose. There is no guidance on when NOT to use it or which sibling to prefer for related tasks (parsing, base64).

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