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

Annotations already cover readOnly, idempotent, non-destructive and closed-world, so the bar is lower. The description still adds real behavioral context beyond them: bearer-token-free access and the fact that execution consumes prepaid run units, which is a cost/auth trait an agent needs before calling.

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 the return payload front-loaded and the behavioral caveat (no token, consumes units) immediately after. Minor redundancy in restating that the metadata call is read-only, but nothing wasteful.

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?

There is no output schema, so the description carries the return-value burden, and it discharges it by enumerating identity, price, endpoint, and access URL. It leaves error/edge behavior unstated, but for a zero-parameter read-only metadata call it is essentially complete.

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 per the rubric the baseline is 4. There is nothing for the description to clarify, and it correctly avoids fabricating parameter detail.

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 (Returns) and a fully enumerated resource set: agent identity, per-task price, MCP endpoint, and access URL. That is clear enough to identify the tool, but it never contrasts itself with the sibling run-management tools, so an agent must infer the distinction from the name alone.

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 implies usage by clarifying that this is a metadata call that 'does not run the model', but it gives no explicit when-to-use or when-not-to-use guidance and names no alternative. The context is useful but routing is left to inference.

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