List payment gateways

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

readOnlyHint=true already tells the agent this is a safe read. The description contributes beyond the annotation by enumerating the returned content (one-line summary, credential configuration status, feature support matrix), which matters since there is no output schema. It does not mention ordering or whether the list can change, but the added disclosure is substantive.

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?

A single sentence that front-loads the action and scope, then lists what is returned. Every clause carries information an agent would otherwise have to discover by calling the tool.

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?

With no parameters, no output schema, and a read-only annotation, the description must carry the return-shape burden, and it does by naming the three payload elements. Only the relative positioning against overlapping sibling tools is left unaddressed.

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 takes zero parameters, so the baseline is 4; there are no arguments whose meaning the description could clarify. The schema is empty and fully documented, so nothing more is needed on this dimension.

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 (list) and resource (every supported gateway), plus what each entry contains. It is clear on its own, but it never contrasts itself with close siblings such as payments_get_capabilities or payments_check_config, which appear to overlap with the feature-matrix and credential-status information it returns.

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?

There is no explicit when-to-use or when-not-to-use guidance and no named alternative. The overview/discovery use case is implied by 'list every supported gateway', which is enough for an agent to infer intent but leaves ambiguity against payments_get_capabilities and payments_check_config unresolved.

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