decode_jwt

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

With no annotations provided, the description carries the behavioral disclosure burden. It explicitly states that JWT signatures are not verified and describes the useful behaviors: converting iat/nbf/exp to dates and flagging alg:none, missing alg, expiry, non-expiring tokens, and long-lived tokens. It does not define thresholds like 'long-lived' or describe malformed-token handling, but the disclosure is still substantial.

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 entire behavior is captured in one efficient, front-loaded sentence. It starts with the core action, then lists all significant outputs and checks without redundant phrasing. The parenthetical 'it says so' is slightly informal but does not waste meaningful space.

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 read-only decode tool with no output schema, the description is complete enough for an agent to invoke it correctly and anticipate the main results. It covers what is decoded, the timestamp formatting, and the security-related flags. Missing details like exact output formatting are not necessary for correct invocation.

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 100% and there is only one parameter, so the schema already fully documents the token parameter, including the optional 'Bearer ' prefix. The description's value is mostly about output behavior rather than adding parameter-level meaning, matching the baseline for high schema coverage.

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 opens with a specific verb and resource: 'Decode a JWT's header and payload'. It also enumerates what the tool reports (date conversion, security flags), making it clearly distinguishable from siblings like decode_layers, convert_timestamp, and identify_hash without needing to open the schema.

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 parenthetical 'no verification' clearly tells agents this is not the tool for signature validation, and the decode/flag behavior makes the intended use obvious. It does not explicitly name an alternative tool or provide formal when-not conditions, so it falls just short of a 5.

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