Decode percent-encoded URL strings into readable text. Use it to convert encoded query parameters or URLs back to their original form.
Decode a URL-encoded (percent-encoded) string.
| Name | Required | Description | Default |
|---|---|---|---|
| encoded | Yes | URL-encoded string to decode. |
Changes observed during successful MCP inspections.
v0.1.11Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds nothing beyond that — no mention of error behavior on invalid percent sequences, encoding assumptions (UTF-8 vs latin-1), or output format — which is the main behavioral gap for a decode utility.
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?
One short sentence with the core verb front-loaded and no filler. There is nothing to trim and nothing buried.
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 one-parameter pure function with full annotation coverage, complete schema documentation and no output schema, the description is nearly sufficient. The only omission is expected behavior on invalid or partially-encoded input, a minor gap for this tool class.
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%: the single `encoded` parameter is already documented as 'URL-encoded string to decode.' The description restates the same idea and adds no syntax, format, or edge-case detail beyond the schema, so baseline 3 applies.
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 ('Decode') and resource ('URL-encoded string'), plus a clarifying synonym '(percent-encoded)' so the agent knows exactly what transformation happens. This is unambiguous against the sibling `url_encode`, which performs the inverse.
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?
Usage is strongly implied by the name/description but never stated: there is no guidance on when to choose this over `url_encode`, what happens on malformed input, or whether '+' is treated as space. For a trivial, single-purpose utility this is acceptable, but it leaves the agent to infer everything.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.