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

Annotations already establish the safe-read profile (readOnlyHint, idempotentHint, destructiveHint=false), so the bar is lower, and the description adds the one behavior that actually matters here: it does not verify signatures. It stops short of disclosing failure behavior for malformed or expired tokens.

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 sentence, front-loaded with the operation and its scope, with zero padding except the vendor tag 'from freedailypro' which does not earn its place.

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?

With no output schema, the description correctly tells the agent what comes back (header and payload, not the signature). For a one-parameter utility this is nearly complete; only error/edge-case behavior is unstated.

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?

There is a single parameter with 0% schema description coverage; the schema only says it is a string. The description does not clarify that the token must be the raw JWT string (three dot-separated segments), leaving the parameter's expected format undocumented in both places.

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 names a specific verb and resource ('Jwt decoder') and pins down the exact scope of output ('header + payload only'), which no sibling tool overlaps with. The trailing 'from freedailypro' is branding noise that adds nothing to purpose, keeping it short of a 5.

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 phrase 'no signature verification' implicitly signals when not to rely on this output (any trust/security decision), which is useful implied guidance. However, it never names an alternative tool or states the precondition that the input must be a well-formed three-segment JWT, so usage is only implied rather than explicit.

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