listPriorities

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds the behavioral context that this is a discovery/lookup operation and that the returned IDs are meant to be reused. However, it doesn't describe the output format or whether the list is ordered, but with a rich output schema present and annotations covering safety, a 3 is appropriate.

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 sentences with no wasted words. The first sentence states the purpose and the second provides the reuse guidance. It is front-loaded with the core action and immediately gives the agent the key information needed to use the tool correctly.

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 zero-parameter, read-only lookup tool with an output schema and strong annotations, the description is nearly complete. It explains why the tool exists and how to use its output. The only minor gap is that it doesn't mention whether the list is exhaustive or ordered, but the openWorldHint annotation and output schema likely cover the return structure. This is a minor gap, not a significant one.

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 tool has zero parameters, so there is no parameter semantics burden on the description. The schema coverage is 100% (vacuously, since there are no properties). The description adds value by explaining the purpose of the output (valid IDs for reuse), which is more than the empty schema provides. Baseline 4 for zero-parameter tools 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's purpose: discovering valid issue priority IDs and names. It specifies the resource (issue priorities) and the action (discover/list), and it explicitly distinguishes its role as a lookup tool for use before filtering, creating, or updating issues. This differentiates it from sibling tools like listStatuses or listTrackers, which serve different lookup purposes.

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 explicitly states when to use this tool: before filtering, creating, or updating issues. It also tells the agent how to reuse the output (as priorityId in listIssues, createIssue, or updateIssue). This is clear, actionable guidance that routes the agent to the correct tool and explains the downstream usage.

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