Decode a percent-encoded URL string back to plain text. Use when parsing query parameters from raw URLs or when displaying encoded values to users.
| Name | Required | Description | Default |
|---|---|---|---|
| input | Yes | URL-encoded string to decode |
| Name | Required | Description | Default |
|---|---|---|---|
| decoded | No |
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {
+ "input": "a%20b%26c"
+ }
+]Output schema / propertiesAdded value: +{
+ "decoded": {}
+}Output schema / (root)Previous value: -nullNew value: +{
+ "additionalProperties": true,
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds usage context but says nothing extra about behavior — e.g., what happens on malformed input (invalid percent sequences) or whether it decodes '+' as space.
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 sentences with zero waste; the core action is front-loaded before the usage guidance.
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, fully documented utility with an output schema and complete annotations, the description covers everything an agent needs to select and invoke it correctly.
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?
There is a single parameter with 100% schema description coverage plus an example, so the schema already documents it fully. The description adds no syntax or format detail beyond what the schema provides, which is the baseline expectation here.
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: 'Decode a percent-encoded URL string back to plain text.' Specifying 'percent-encoded URL' clearly differentiates it from siblings like base64_decode, decode_jwt, and url_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?
Explicitly names when to use it: 'parsing query parameters from raw URLs' or 'displaying encoded values to users.' It gives clear context but does not mention exclusions or point to url_encode for the reverse operation.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.