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

Goes beyond the readOnly/idempotent/non-destructive annotations by disclosing the auth requirement (no bearer token needed) and the billing behavior (execution consumes prepaid run units), which are exactly the kinds of traits annotations cannot express. It lacks any note on rate limits or error behavior, so not a full 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?

Two sentences, zero filler, and the most decision-relevant facts — what it returns and that it is a non-billable-per-token metadata call — are front-loaded.

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 parameters, no nested objects, and no output schema, the description carries the full burden of describing the response, and it does so by listing the returned fields. Annotations cover the safety profile and the description covers auth and billing, leaving nothing an agent needs to invoke it correctly.

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 takes zero parameters, so there is no argument semantics to add beyond the schema; baseline for a no-parameter tool is 4. The description correctly implies a simple, call-with-nothing access-info lookup.

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 (returns this agent's identity, price, MCP endpoint, access URL) and enumerates the exact return fields. The phrase 'This metadata call does not run the model' cleanly separates it from the run-oriented siblings (create_run, get_run_status, get_run_result, cancel_run).

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 clear context for use: it is a metadata/access-information call that does not run the model, does not need a bearer token, and whose execution consumes prepaid run units. It does not explicitly say when to prefer it over a sibling or name an alternative, so it stops short of a 5.

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