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

Annotations already declare readOnlyHint=true/destructiveHint=false, so safety is covered; the description adds the ordering guarantee ('newest first') and the REST-equivalent behavior ('Mirrors GET /api/v2/repos/.../actions/runs'). It stops short of describing paging behavior or what a run record contains, which keeps it at a strong 4 rather than 5.

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?

Front-loaded with purpose and scope in the first sentence, and the routing hint follows immediately. The closing parenthetical citing issue #10493 is motivational rather than operational and is the one sentence that does not fully earn its place.

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 7-parameter read tool with no output schema, the definition covers purpose, ordering, filters and downstream use well; the main omission is any indication of the returned shape or paging semantics (offset/limit interplay) that an agent would need to iterate results.

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 coverage is 71%, so most parameters are self-documenting; the description only re-lists branch/status/event as 'optional filters', which the schema already spells out (including branch ref syntax and status values). It adds no format or interaction detail beyond the schema, so the baseline 3 holds.

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+resource ('List a repository's workflow runs'), plus ordering and filter scope, and explicitly differentiates from the siblings it feeds (get_workflow_run / cancel_workflow_run). An agent can place it precisely in the workflow-run tool family without opening the schema.

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?

States when to use it directly: 'this is how an agent finds the run ids to inspect or cancel', naming the two downstream tools it enables. The issue note reinforces the trigger condition (discovering stale queued runs), leaving nothing to inference.

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