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

Goes well beyond the annotations: it discloses that Creative Credits are spent, that a mismatched price is refused with nothing charged, that a repeated key never double-charges, and that the result is asynchronous and lands in the brand library. This is exactly the economic and side-effect context the idempotentHint/destructiveHint flags cannot convey.

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?

Front-loads the action, then cost semantics, then the follow-up step — a sensible ordering with no filler. The middle sentence is long and packs three separate rules together, which slightly hurts scanability but every clause is load-bearing.

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 an async, credit-spending, eight-parameter tool with no output schema, the description covers everything an agent needs: inputs sourced from plan_logo, cost guard, idempotent retry, and the fact that completion is observed via get_job rather than a direct return. No material gap remains.

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 an extra point by tying `expected_credit_cost` to plan_logo's `credits`/`refine_credits` and explaining why `idempotency_key` must be stable. It does not add anything for `direction_prompt`, `logo_type`, or `direction_label` beyond what the schema already says.

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 ('Draw ONE logo direction'), names the upstream source (plan_logo), and the capitalization of ONE makes the one-direction-per-call scope unambiguous. An agent can distinguish this from plan_logo and from other creation tools without opening the schema.

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 encodes the workflow: take the prompt and price from plan_logo, use `refine_credits` when refine is set, then poll get_job with the returned job_id. It also states the retry condition (reuse the idempotency key) and what happens on a price mismatch, so the agent knows when and how to call it versus its siblings.

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