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

Goes beyond the annotations by disclosing the billing model: 1 Creative Credit per concept with refunds for failures. This is real behavioral context an agent needs before spending a user's credits, and it is consistent with readOnlyHint/idempotentHint (nothing is created). It stops short of saying whether the quote is stable over time or how failures are signaled.

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 compact sentences: the pricing/what-happens first, then the chaining instruction. Zero filler and the most decision-relevant fact (no artifacts created, credits at stake) is 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 output schema, the description supplies the one return value that matters (`credits`), plus cost and refund semantics and the downstream call. Nothing an agent needs to invoke this correctly or act on its result 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 coverage is 100%, so the baseline is 3; the description earns extra by naming the returned `credits` field, which no output schema documents, and by tying pricing to 'per concept', reinforcing the `count` parameter's cost implication.

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?

Uses a specific verb ('Price') with a specific resource ('a set of private image concepts') and immediately negates the adjacent action ('without making anything'), which separates it cleanly from explore_image_concepts and the many plan_* siblings.

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?

Explicitly frames this as a pre-flight quote step and names the follow-up tool plus the exact field to carry forward ('Send the returned `credits` as `expected_credit_cost` on explore_image_concepts'). That is a concrete when-to-use and what-to-do-next instruction, not an implied one.

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