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

No annotations are provided, so the description carries the behavioral-disclosure burden. 'Value discarded' helpfully indicates the check is non-retaining, but there is no information about side effects, network access, permissions, or why the schema contains many unrelated fields such as url, city, feed, and path.

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 extremely terse and front-loaded, with no wasted words. It is appropriately concise for a simple shape-check label, though the brevity contributes to the overall under-specification.

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 tool with nine optional parameters, no annotations, and no output schema, the description is completely inadequate. It mentions only JWT shape, while the schema exposes unrelated ref, url, city, feed, host, json, path, zone, and query fields with no explanation of how they relate to the stated purpose.

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%, so the schema itself already explains each of the nine parameters in detail. The description adds no parameter-level meaning beyond what the schema provides, which matches the baseline of 3 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 identifies a specific resource (JWT header.payload.sig) and a shape-checking purpose, so it is not tautological. However, it is fragmentary and does not explicitly differentiate jwt-hdr from the many other shape-checking siblings such as domain-shape or github-repo-shape.

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 explicit when-to-use guidance or mention of alternatives. The name and description imply a JWT-shape use case, but the agent receives no routing logic for choosing this over validate-json, domain-shape, or other sibling shape checks.

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