jwt_decode

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

With no annotations, the description carries the full behavioral burden, and it does disclose the key caveat that the signature is not verified — a genuinely useful security note an agent could not infer. However, it says nothing about malformed-token handling, whether errors are thrown or partial results returned, or whether expired/invalid tokens are still decoded, which matters 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 tight sentence with the operation front-loaded and the important caveat placed immediately after in parentheses; nothing is wasted. It is arguably too terse given the gaps it leaves, but as a piece of writing it is efficient and well-ordered.

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 utility with no output schema, the description should at least indicate that the result is the parsed header and payload rather than raw text, and it only half does so. It is adequate to attempt a call, but missing error behavior and output shape details keep it at a minimum-viable level.

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 0% for the single 'token' parameter, so the schema supplies only the type with no description. The description implies the parameter is the JWT itself but does not clarify format expectations such as whether a 'Bearer ' prefix or surrounding whitespace must be stripped, leaving a real ambiguity unaddressed.

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 (JWT header and payload), which precisely distinguishes it from the encoding/decoding siblings such as base64_decode and url_decode. It does not explicitly name an alternative, but the resource is unambiguous, so an agent can select it correctly.

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 description implies the use case (you have a JWT and want to inspect it) but never states when to use this versus base64_decode or other siblings, nor any prerequisites. Usage is inferable from the name and verb but not spelled out.

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