decode_jwt

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It discloses that the tool shows header, payload, expiration status, and a human-readable explanation. However, it does not mention whether the token is validated (signature check) or just decoded, whether it makes external calls, or any side effects. For a read-only decoding tool, this is adequate but not rich.

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 a single sentence that is front-loaded with the main verb and resource, then lists the key outputs. Every word earns its place; no fluff or repetition.

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 decode tool with no output schema, the description covers the main outputs (header, payload, expiration status, explanation). It doesn't specify the exact structure of the output, but the description's mention of 'human-readable explanation' gives a sense of what to expect. Given the tool's simplicity, this is nearly complete. A small gap is not stating whether the token is verified or just decoded.

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%: the only parameter 'token' is described as 'The JWT token to decode'. The description adds the context that it's an AgeKey JWT token and that the output includes expiration status and explanation, which adds some meaning beyond the schema. Baseline 3 is appropriate since the schema already documents the parameter.

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: 'Decode and explain an AgeKey JWT token.' It specifies the resource (AgeKey JWT token) and the action (decode and explain), and lists the outputs (header, payload, expiration status, human-readable explanation). This distinguishes it from siblings like explain_error, which explains errors, and get_code_sample, which provides code samples.

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 usage: when you have an AgeKey JWT token and need to decode it. However, it does not explicitly state when to use this tool versus alternatives, nor does it mention any exclusions or prerequisites. The sibling tools are mostly about organization/application management, so the context is clear, but the description doesn't explicitly guide selection.

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