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

With no annotations, the description carries the full burden of behavioral disclosure. It only states 'Key discarded', implying no side effects, but does not explain what the check returns (e.g., boolean, error message) or any format rules. The schema descriptions repeat the 'discarded' note but add no operational detail, so transparency is minimal.

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 brief (two sentences) and front-loaded with the core verb and object, which is good for conciseness. However, it omits essential mapping information, so the brevity is not effective. It earns a middle score for structure because it is not verbose, but it sacrifices needed content.

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 parameters, no required fields, and no output schema, the description is grossly insufficient. It does not specify how to invoke the tool, which parameter holds the Jira key, what the tool returns, or any constraints. An agent would be unable to call this tool correctly based solely on the provided information.

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?

Although schema coverage is 100%, each property description gives a generic meaning (e.g., 'Git ref name') and repeatedly says 'discarded after the shape check'. None of these descriptions connect to a Jira key. The tool description adds no clarification, so an agent cannot map any parameter to the key being checked. This is a critical gap.

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 a clear action ('Check a Jira issue key shape') but does not specify which input parameter contains the key. The schema lists nine unrelated string parameters (ref, url, city, feed, host, json, path, zone, query), none named 'key', so an agent cannot determine what to pass. This ambiguity severely undermines purpose clarity.

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 provides no guidance on when to use this tool versus sibling shape-checkers (domain-shape, github-repo-shape, figma-url-shape). It does not mention alternatives, conditions, or exclusions, leaving the agent without a basis for tool selection.

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