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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds the required authorization scope ('billing.read'), which is useful behavioral context, but does not discuss data freshness, pagination, rate limits, or external-call behavior beyond the open-world annotation.

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 a single long, comma-heavy sentence listing many returned data categories. The length is partly justified because no output schema exists, but the run-on structure makes it harder to parse than a concise front-loaded summary followed by grouped return-value details.

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 no output schema and no parameters, the description does the necessary work of enumerating the data returned and states the required scope. It is largely complete for a read-only retrieval tool, though it omits differentiation from list_runner_jobs and does not describe response shape or pagination.

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 and schema description coverage is 100%, so the baseline is 4. There are no parameter semantics for the description to clarify beyond what the empty schema already communicates.

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 identifies the resource as GitHub runners and enumerates the specific data returned: runs-on labels, vCPU/memory/price, account concurrency, linked organizations, monthly minutes/cost, actions cache, and Docker cache. It does not, however, distinguish this tool from the sibling list_runner_jobs, which an agent might reasonably confuse with runner-related retrieval.

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 provides no explicit when-to-use guidance, no exclusions, and no alternatives. It states an authorization scope ('billing.read') but does not explain when an agent should call get_runners versus list_runner_jobs or other runner-related tools.

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