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

No annotations are provided, so the description carries full behavioral disclosure. It reveals the cart requirement, the checkout-screen visibility, and a critical caveat that SBP won't auto-complete. This is rich behavioral context beyond a simple 'list' tool, effectively warning agents about a potential failure mode.

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?

Three sentences, each earning its place: purpose, prerequisite, and a crucial warning. Front-loaded with the primary action. No filler, no redundancy. The structure aids quick comprehension.

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 simple list tool with no params and no output schema, the description is fully sufficient. It covers what it returns, when it is usable, and why a specific payment method might fail. It also references a sibling tool (place_order) for the payment parameter, providing necessary integration context.

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?

The tool has zero parameters, so the schema is an empty object. Per guidelines, baseline is 4 for zero params. The description doesn't need to elaborate on non-existent parameters, though it adds useful output context (available methods and selected one), which is a minor bonus beyond the baseline.

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 clearly states the tool's function: 'Shows available payment methods (cards, Card Pay, SBP) and the currently selected one.' The verb 'shows' and specific resource ('payment methods') distinguish it from siblings. It also notes the prerequisite of a non-empty cart, adding clarity about when the tool is relevant.

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 states when it can be used: 'A NON-EMPTY cart is required (methods are visible only on the checkout screen).' Provides an important exclusion: SBP requires manual confirmation and will not auto-process; directs users to choose card/Card Pay for auto-ordering via the 'payment' parameter in place_order. This gives clear guidance on when to use the tool and what to avoid.

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