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

There are no annotations, so the description carries the behavioral burden. It does disclose that the key is discarded after the check, which is a useful side-effect signal. However, it does not describe return behavior, error conditions, or whether the operation is strictly read-only beyond the word 'Check'.

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 very short and front-loaded, with no filler. The second sentence 'Key discarded' adds a side-effect detail, though the overall brevity contributes to the lack of parameter and return clarity.

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 no annotations and no output schema, the agent is left without knowing what output to expect (boolean, canonical key, error) and which of several schema fields to supply. The mismatch between the description's 'key' and the schema's unrelated-looking properties makes the tool under-specified for reliable invocation.

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?

The schema has seven properties with individual descriptions, but none is an obvious 'key' parameter: ref, url, city, feed, host, json, path. The description never explains which property carries the Jira issue key, and 'ref' is described as a Git ref name, making parameter mapping ambiguous for an agent.

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 action ('Check') and a specific resource ('a Jira issue key shape'), which distinguishes it from sibling shape tools like github-repo-shape or domain-shape. It is concise and clear, though it does not specify what the check returns or what 'shape' means.

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 Jira-specific wording implies this is the tool to use when validating or checking a Jira issue key's format. However, it provides no explicit when-to-use or when-not-to-use guidance and does not name any alternatives, so an agent must infer the intended use case.

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