Decode untrusted JWT claims and optionally compare timestamps; never verifies a signature. FREE during validation. No key, credits, wallet or preparation needed. Supply your task in input. Existing source and input limits apply.
| Name | Required | Description | Default |
|---|---|---|---|
| input | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| scope | Yes | ||
| claims | Yes | ||
| header | Yes | ||
| expired | Yes | ||
| warnings | Yes | ||
| notYetValid | Yes | ||
| signatureVerified | Yes |
Changes observed during successful MCP inspections.
Input schema / properties / maxPriceMicroUsdRemoved value: -{
- "description": "Optional legacy field; ignored in free mode.",
- "minimum": 0,
- "type": "integer"
-}Input schema / properties / requestIdRemoved value: -{
- "description": "Optional legacy field; ignored in free mode.",
- "type": "string"
-}Input schema / properties / maxPriceMicroUsd / descriptionPrevious value: -"Explicit maximum new debit; 0 means recovery only."New value: +"Optional legacy field; ignored in free mode."Input schema / properties / maxPriceMicroUsd / maximumRemoved value: -999999999999Input schema / properties / requestId / descriptionPrevious value: -"Persist the ID returned by agent_utilities_prepare. Reuse after uncertainty."New value: +"Optional legacy field; ignored in free mode."Input schema / properties / requestId / patternRemoved value: -"^\\d{13}_[A-Za-z0-9_-]{16,80}$"Input schema / requiredPrevious value: -[
- "input",
- "requestId",
- "maxPriceMicroUsd"
-]New value: +[
+ "input"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly and non-destructive. The description adds genuinely useful behavioral context beyond them: it never verifies the signature, is free during validation, requires no key/credits, and notes that source/input limits apply. However, it doesn't say whether the comparison result is returned or how timestamps are interpreted.
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 core purpose is front-loaded, which is good, but the definition burns two sentences on pricing/marketing ('FREE during validation', 'No key, credits, wallet or preparation needed') and includes the awkward 'Supply your task in input'. Some fat could be trimmed.
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?
An output schema exists, so return values needn't be explained. Still, for a tool with a nested required object at 0% schema coverage, the description under-documents token format and the atUnixSeconds comparison semantics, leaving the agent to guess how to populate the request.
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 0%, so the description must carry the burden, and it largely fails to. It hints at 'claims' (token) and 'compare timestamps' (atUnixSeconds), but 'Supply your task in input' is confusing and misdescribes an input object that actually requires a token. Little usable parameter guidance is added.
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 states a specific verb and resource ('Decode untrusted JWT claims') and immediately scopes it with a critical caveat ('never verifies a signature'). No sibling tool operates on JWTs, so it is unmistakably distinct from the security_* audit/scan/redact family.
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 implied by the 'untrusted' framing (decode claims you don't fully trust), but there is no explicit when-to-use/when-not statement and no alternatives are named. Adequate but leaves the agent to infer context.
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.