jwt

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

No annotations are provided, so the description carries the full burden. It fails to mention whether signatures are verified, how malformed tokens are handled, or that decode/check_expiry might not validate the token. 'Not for production authentication' hints at security limitations but is too vague to fully disclose the tool's 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?

The description is two concise sentences with no fluff. The primary purpose is front-loaded, and the important caveat about production authentication is clearly appended. Every sentence earns its place.

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?

There is no output schema, so the description should explain return values, but it doesn't specify what each action returns. It also omits conditional parameter requirements (e.g., token needed for decode/check_expiry) and error behavior. For a tool with multiple modes and nested objects, this leaves significant gaps for an agent to fill.

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%, so each parameter already has a description. The tool description does not add any extra parameter-level detail beyond the schema; it merely restates the actions via the enum. With high schema coverage, the baseline score of 3 is appropriate.

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 clearly states the tool's function with specific verbs and resources: decode JWT tokens to inspect header/payload, check expiry, or create unsigned JWTs for testing. It distinguishes this tool from generic siblings like encode_decode and hash by focusing exclusively on JWT operations.

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 phrase 'Not for production authentication' provides an explicit exclusion, and 'for testing purposes' suggests the intended context. While it doesn't name sibling alternatives explicitly, the guidance is clear enough for an agent to know when not to use it.

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