issue_stats

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

With no annotations, the description must carry the burden of behavioral disclosure. It indicates a read-only aggregation operation through 'Aggregate counts' but does not explicitly state that issues are not modified, nor does it disclose any limits, pagination, or error behavior. The ISO-8601 note for timestamps is useful but pertains to parameters, not behavior.

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 two sentences with zero filler. The core purpose is front-loaded, and the timestamp format detail is added only as needed. It is appropriately sized for a simple aggregation tool.

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's simplicity, an output schema, and all-optional parameters, the description covers the essential context: what it aggregates, by which dimensions, and the timestamp format. Minor gaps like inclusivity of since/until are not critical for a counts tool, and the output schema handles return structure.

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?

Schema description coverage is 0%, so the description must compensate. It explains that since/until are ISO-8601 timestamps and implies group_by accepts status, kind, severity, or source. However, it does not explicitly link these values to the group_by parameter or list all possible values, leaving some ambiguity 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 uses a specific verb ('Aggregate') and resource ('issue counts') and lists grouping dimensions (status, kind, severity, or source). This clearly differentiates it from sibling tools like search_issues (which likely returns lists) and get_issue (single issue). However, it does not explicitly name an alternative or state what it is not, so it is not a 5.

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 implies usage for count-based aggregation rather than listing, but it does not explicitly say when to use this tool versus search_issues or get_issue. There is no mention of exclusions or prerequisites, leaving the decision to the agent's inference.

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