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

Annotations only supply destructiveHint=true, so the description carries most of the behavioral weight and does it well by hammering the money-movement and charge semantics. It stops short of disclosing auth/permission requirements, what a capture=false authorization leaves behind, or error/decline behavior, so it is strong but not complete.

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 highest-stakes fact (money movement) before mechanics, and every sentence carries information. The capitalized emphasis is slightly heavy-handed and the source-object examples echo the schema, so it is efficient but not maximally tight.

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 11-parameter, nested-object, money-moving tool with no output schema, the description leaves the agent without any picture of the response (payment id, status, authorization outcome) or of idempotent-retry behavior beyond the schema's one-line hint. The required core is covered, but the gaps matter at this complexity level.

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 description coverage is 100%, so the schema already documents all 11 parameters, including the minor-units convention and idempotency key. The description restates `amount`/`currency` and gives `source` object examples that largely duplicate the schema, adding marginal value only. Baseline 3 applies when the schema does the heavy lifting.

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 ('CREATES a payment') and immediately disambiguates the two modes (authorization vs. immediate capture) plus the underlying API call (POST /payments). The 'MOVES MONEY: charges a card' framing separates it cleanly from siblings like checkout_capture_payment, checkout_refund_payment, and checkout_void_payment.

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 implies when to use the tool (new payment, either authorize-only or immediate capture), which is useful context, but it never names alternatives or exclusions — nothing tells the agent to prefer checkout_capture_payment for an already-authorized payment or checkout_refund_payment to reverse one. Usage is inferable rather than explicit.

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