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

With no annotations, the description carries the full behavioral burden. It does disclose one useful trait: the key is discarded rather than retained or echoed. However, it does not describe the return value, error behavior, or what happens for an invalid shape, leaving a meaningful gap for a validation tool.

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?

Two short sentences with no filler, and the main action is front-loaded. The 'Key discarded' sentence earns its place as a behavioral warning without adding unnecessary length.

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 no annotations and no output schema, the description omits essential operating details: what the result looks like, whether invalid keys error or return false, and the exact validation rule. The schema provides some support, but an agent still lacks enough context to confidently interpret the tool's behavior.

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 already documents all parameters with descriptions and provides an example format for issue_key, so description coverage is high. The description adds only the discarded-key lifecycle note, but does not explicitly map the tool to the issue_key parameter or refine its accepted format.

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?

States a specific verb and resource: 'Check a Jira issue key shape.' This clearly separates it from sibling shape validators like github-repo-shape or wiki-title-ok. The only ambiguity is what 'shape' exactly means, but the issue_key schema example (PROJ-123) fills that gap.

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?

No guidance on when to use this tool versus alternatives, no 'use when' conditions, and no exclusions. An agent can infer it is for validating Jira issue keys from the name and issue_key property, but the description never explicitly says so.

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