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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, but the description goes well beyond them: it explains that pricing runs through the same server-side path as a real order, that no order is placed and nothing is charged, and it interprets the shape of the result via payment_methods (connected GrowVib account over OAuth, or x402 with no account). That is exactly the kind of behavioral and auth context annotations cannot express.

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?

It is front-loaded with the key constraint ('call before every order, never total prices yourself'), and each sentence carries distinct information. It is somewhat long and dense, especially the final sentence about payment methods and OAuth endpoints, which could be tightened, but nothing is wasted repetition.

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 pricing-read tool with no output schema, the description is complete: it states what is returned (unit price and total in USD), how pricing is computed, that no side effect occurs, and how the result maps to payment paths. An agent has everything needed to invoke and interpret it 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 100%, so the schema already documents service_id, quantity and service_option_id. The description adds the procedural context of 'quantity bounds and rounding are applied here,' which is meaningful, but it does not clarify parameter syntax, accepted ranges or option-id sourcing beyond what the schema states. Baseline 3 is appropriate when the schema carries the parameter burden.

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 description delivers a precise verb+resource ('Get the exact price that will be charged') and explicitly distinguishes itself from the catalog tools by warning not to total up per-1000 prices yourself. It also frames itself relative to the ordering siblings by defining what it does NOT do ('places no order and charges nothing'). An agent can cleanly separate this from search_catalog and create_paid_order.

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 gives an explicit workflow directive: 'Call this before every order,' states the alternative behavior to avoid ('never total up the per-1000 prices the catalog tools return yourself'), and names the real-order path for conversion (create_paid_order / REST endpoint). This is a strong, actionable when-and-how-when-not statement.

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