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

No annotations exist, so the description carries the full burden and does so well: it documents the atomicity guarantee, the exact meaning of both return values, the blocked-issue edge case, the permission requirement (canEdit), and the assignee restriction. These are non-obvious runtime behaviors an agent could not infer from the schema.

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-loads the core action and its state change, then layers return semantics, atomicity, and constraints in short declarative sentences. Dense but every sentence carries operational information; no filler.

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?

Despite having no output schema, the description fully specifies the boolean return and how to react to each value, plus the permission and identity preconditions and the recommended next call. Nothing needed to invoke it correctly is missing.

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?

One parameter with 100% schema description coverage; the schema already explains runId and its provenance (list_agent_runs). The description adds no format or validation detail beyond the schema, so baseline 3 applies.

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 (Claims) and resource (a Ready agent run), plus the resulting state transition (moving it to Working). Distinguishes itself from siblings like create_agent_run and cancel_agent_run by naming the exact lifecycle state it operates on.

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?

Gives explicit when-to-act guidance (claim a Ready run, skip on false), the precondition (only the issue's assignee can claim; requires canEdit), and routes the agent to the follow-up tool by name: edit_issue_status. This is close to a complete decision procedure.

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