list_servers

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, and the description largely restates these ('read-only and idempotent'). It does add one genuine piece of context — that it is a pure in-memory catalog with no external fetch — but adds nothing about catalog scope limits, staleness, or rate behavior.

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 purpose, then usage, then behavior in a clean three-part structure. The enumeration of message families is long but earns its place by defining catalog scope; only the closing 'read-only and idempotent' clause is redundant with annotations.

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 an output schema present, return values need not be described, and the description covers purpose, usage and safety. It does not, however, distinguish itself from the sibling 'list_families', which overlaps with the message-family enumeration it advertises.

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 is nothing for the description to clarify. It correctly avoids inventing filtering options that the empty schema does not support.

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 (the ISO 20022 suite the gateway knows), and enumerates the concrete contents (pain/pacs/camt/acmt families, E&I messages, specialized servers). An agent can tell this is a discovery/catalog tool distinct from action tools without opening a schema.

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 labeled 'When to use' (discover available specialized servers and route cross-cutting workflows) and 'When NOT to use' (operational parsing/generation), naming the alternative tools 'generate', 'parse', 'validate'. This is the full when/when-not/alternatives pattern.

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