jira_get_custom_fields

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

Annotations already declare readOnlyHint=true, so the description's statement of 'retrieves' is consistent. The description adds that it shows fields and their identifiers, but does not disclose any additional behavioral traits such as pagination, performance implications, or that the filter is optional. This is adequate but not extensive.

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 three sentences, front-loading the main action in the first sentence, then details, then usage context. Every sentence adds value; no redundant or vague phrasing.

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 the tool is simple (one parameter, no output schema, read-only), the description adequately covers what it does and returns. It could mention that it returns a list or array, but the overall completeness is high.

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 covers the single optional parameter projectKey with a clear description. The tool description does not add any extra semantic meaning beyond what the schema provides (e.g., examples, value constraints). With 100% schema coverage, baseline 3 is appropriate.

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 clearly states the tool retrieves all Jira custom fields and enumerates what information it returns (names, IDs, types). It distinguishes itself from sibling tools like jira_get_issue_types or jira_get_priorities which return different metadata.

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 a use case ('useful for discovering what custom fields exist'), but does not explicitly state when to use this tool over alternatives or note any prerequisites. Since there is no direct sibling for custom fields, the lack of comparison is acceptable, but more explicit guidance would improve score.

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