Pay: payment options

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the 'Read-only' sentence largely repeats structured data. The description does add real context by framing the result as what a client app will be offered on a given platform/storefront, but says nothing about caching, freshness, or return shape.

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 short enough, but the first two sentences are redundant ('Show available payment providers' immediately followed by 'Shows which payment providers...'). The redundant opening costs a point against otherwise efficient structure.

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 two-parameter read-only lookup with no output schema, the description covers scope, inputs, and intent adequately. It could say more about the shape of the returned provider list, but nothing essential for invocation is missing.

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 both platform values (ios/android/web) and the storefront country code. The description restates the platform enum and the optional storefront without adding syntax or example beyond the schema, so baseline 3 applies.

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 (show) and resource (available payment providers) scoped to a platform/storefront, which is clearly distinct from pay_methods or pay_connect work. It never explicitly differentiates itself from the closest siblings (pay_methods, pay_plans_list), so it stops short of a 5.

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?

Gives a concrete use case: 'use it to see what a client app will be offered', which tells the agent the context (client-facing preview). There is no explicit when-not-to-use or named alternative tool, so it is clear context but not full routing guidance.

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