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

Beyond the annotations, it discloses a lot: credits are spent, insufficient balance returns balance/shortfall/creditsInformationUrl with NO checkout, identical stage+argument retries reconcile the same operation, new authorizations enforce pause/cap plus OAuth studio.spend and exact-quote checks, and the response can wait up to 45 seconds. This goes well past destructiveHint/idempotentHint and gives the agent the failure and timing model.

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?

The committing action is front-loaded in the opening clause and each subsequent sentence covers a distinct topic (stages, retries, auth, response). It is dense and long for a single paragraph, but there is essentially no filler or repetition of the title.

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 9-parameter, credit-spending, open-world mutation with an output schema, the description covers preconditions, per-stage behavior, balance-failure outcome, idempotency, auth requirements and the wait/response shape. Since an output schema exists, return-value detail is not required, and what is stated is enough to invoke 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?

Schema coverage is already 89%, so the baseline is 3, but the description adds cross-field logic the schema cannot express — that stage:pictures binds one approval across pictures and video using operationId, quoteToken, priceVersion, quotedCredits and revisionId, and that stage determines which revisionId is valid. That relational guidance is genuinely additive.

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?

The first sentence names a specific verb and resource (spends Brix36 credits, starts the quoted work) and scopes it to a customer-approved quote, which distinguishes it from the sibling studio_generation_quote and studio_generation_status. An agent can tell immediately that this is the committing step after a quote, not the quoting or polling step.

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 states the precondition (customer financial approval) and distinguishes the two modes clearly: chat-mode stage:pictures records one approval for pictures and video, while stage:video starts video under that same approval subject to readiness gates. It also covers retry semantics and legacy confirmationToken paths, though it never names the concrete sibling to call first (studio_generation_quote) in the description text.

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