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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds real interpretive value: the fields surfaced (status, runner start times, failure/queue reason, cost, billing method, commit) and the caveat that a runner start failure is distinct from the GitHub conclusion.

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?

Three tight sentences, front-loaded with the use case and followed by return contents and a key caveat. The field enumeration is somewhat list-like but each item earns its place for a diagnostic 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?

With an output schema present, the description needn't detail return values, yet it summarizes them and adds the failure-vs-conclusion nuance. Combined with 100% schema coverage and full annotation coverage, an agent has enough to call this correctly; only explicit sibling routing 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?

Schema description coverage is 100%: jobId is documented as coming from list_runs and explicitly distinguished from the GitHub workflow run ID, and workspaceId points to list_workspaces. The description adds nothing about the parameters, so the schema carries the load and the baseline of 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?

The description states a specific verb and resource: examine ONE GitHub Actions job attempt in Runzumi, or its cost. The word 'one' implicitly separates it from the list_runs sibling that returns many, though no sibling is named explicitly. Purpose is unambiguous.

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?

'Use this to examine one slow or failed GitHub Actions job attempt ... or its cost' gives a clear diagnostic context for when to reach for it. It does not name an alternative tool or state when NOT to use it, so it falls short of explicit routing guidance.

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