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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered. The description adds genuinely non-structured context: no bearer token required for this call, and that execution (not this call) consumes prepaid run units — useful cost/auth information an agent can't derive from the annotations.

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 tight sentences with no filler. The return-value content is front-loaded and the auth/cost caveat follows immediately; every clause carries information.

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 zero-parameter, annotation-covered metadata call with no output schema, the description supplies the return fields (identity, price, endpoint, URL) plus the auth and cost behavior. Nothing an agent needs 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?

The tool takes zero parameters, so the baseline of 4 applies. The description appropriately says nothing about arguments and instead spends its text on return fields and call semantics.

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 and resource ('Returns this agent's identity, listed per-task price, MCP endpoint, and access URL') and enumerates exactly what comes back. This is clearly distinguishable from the run-lifecycle siblings (create_run, get_run_status, get_run_result, cancel_run), which all deal with executions rather than agent metadata.

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?

It implicitly positions itself as a pre-execution metadata call by clarifying it 'does not run the model' and that execution is what consumes run units. That gives an agent a clear condition for reaching for it, though it never explicitly names a sibling alternative or a when-not-to-use case.

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