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. 'Key discarded' usefully signals that the received key is not retained, and 'check' implies a non-mutating operation. However, the description does not say whether the tool returns a boolean, an error, a normalized key, or what exactly constitutes a valid shape.

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 appropriately short and front-loaded with the main action, with no filler sentences. It loses one point because the term 'Key' in the second sentence does not correspond to any schema property, making the concise phrasing slightly misleading.

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 9 parameters, no output schema, and no annotations, this description is materially incomplete. It fails to identify the relevant parameter, define the expected Jira key shape, or describe the return value, so an agent cannot reliably invoke the tool.

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%, the description refers to a 'key' while the input schema contains no key property; it contains ref, url, city, feed, host, json, path, zone, and query. The description therefore adds no usable parameter mapping and actively conflicts with the schema, leaving an agent unable to determine which input to populate.

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 specific verb ('Check') and a specific resource ('Jira issue key shape'), which clearly distinguishes it from sibling shape tools like github-repo-shape, domain-shape, or figma-url-shape. The ambiguity about which parameter carries the key is an input-mapping concern, not a purpose clarity concern.

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 use case is implied: use this tool when you need to validate the shape of a Jira issue key. There is no explicit guidance about when not to use it, nor any mention of alternative tools that might be better suited for other key or identifier formats.

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