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 omits the most important trait: whether this merely base64-decodes the token or also verifies the signature. It also says nothing about behavior on malformed/expired tokens or whether a 'Bearer ' prefix is tolerated.

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?

A single front-loaded sentence with no filler, and the output parts are listed first. It is sized correctly, though the brevity comes at the cost of the missing behavioral detail rather than being a deliberate trim.

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 is the only source of return-shape information; listing header/payload/signature partially covers that. But it omits the decode-vs-verify distinction and any error behavior, leaving meaningful gaps for a security-relevant tool.

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 description must compensate and does not. It never states that the value is the raw dot-separated JWT string, nor any format or length expectations.

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 token) and enumerates the output parts (header, payload, signature), so an agent knows exactly what comes back. It doesn't explicitly contrast with the semantically closest sibling, token_verdict, but among the mostly unrelated utility siblings the purpose is unambiguous.

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?

There is no guidance on when to use this versus alternatives, and the sibling list includes 'token_verdict', which an agent could easily confuse with decoding. No prerequisites, no statement about whether an encoded/verified token is needed first.

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