list_payment_gateways

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

Annotations already mark readOnlyHint=true, and the description adds meaningful context that gateways are plugin-provided and immutable via API. This explains why there is no create/delete operation and aligns with the read-only annotation, adding value beyond annotations. No contradictions.

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 description is two short sentences, front-loaded with the primary action and resource, followed by a concise but relevant note about plugin-provided gateways. No filler or redundant information.

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 one optional parameter and a read-only annotation, the description is complete. It covers the scope (all gateways), the immutable nature, and is fully supported by the schema. No output schema exists, so return format is not required to be explained.

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 input schema fully documents the single optional 'fields' parameter with a default list of fields. The tool description does not mention parameters, but with 100% schema coverage, the schema carries the semantic burden. Baseline 3 is appropriate.

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 lists all available payment gateways, using a specific verb (list) and resource (payment gateways). It also notes gateways are plugin-provided and cannot be created/deleted via API, which effectively distinguishes it from sibling tools like get_payment_gateway and update_payment_gateway.

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?

The description implies usage by stating it lists all gateways and clarifying they cannot be created/deleted, which tells the agent this is the read-only listing operation. However, it does not explicitly reference alternatives (e.g., 'for a single gateway, use get_payment_gateway'), so it falls short of full explicit guidance.

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