decode_jwt

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

With no annotations, the description carries the full burden. It discloses non-verification of signatures, lists decoded parts (header, payload, signature), and mentions base64 decoding. Could add what happens on invalid input, but current detail is strong.

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?

Three short, front-loaded sentences with no redundancy. Every sentence adds value: purpose, usage note, parameter explanation.

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?

Given output schema exists, return values are covered. Description includes purpose, usage, and parameter detail. Complete for a single-parameter tool with no additional complexity.

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% but the description adds a parameter description: 'token — The full JWT token string (3 dot-separated base64 parts).' This compensates by explaining the required format beyond the schema's simple type and title.

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 states 'Decode a JWT token into its header, payload, and signature parts' with a specific verb and resource, clearly distinguishing it from siblings like 'encode_base64' or 'verify_jwt'.

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?

Explicitly says 'Use this to inspect JWT tokens without verifying signatures', providing clear context and conditions. No when-not or alternatives are given, but it suffices for a simple inspect tool.

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