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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: MT103 and pacs.008 responses include a `tracing_note` explaining UETR recovery, which tells the agent something about return content it would not otherwise know.

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-loaded with the core purpose, then the two usage modes, then concrete examples. Every sentence adds distinct information (domain coverage, field-location use case, response detail) with no filler.

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?

An output schema exists so return values need not be documented, yet the description still flags the tracing_note behavior. With one optional parameter fully documented and clear usage modes, nothing an agent needs to invoke this correctly 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 coverage is 100% and the parameter's description already covers the case-insensitive/omit behavior, so the baseline is 3. The description goes further by naming concrete valid values (MT103, pacs.008, MT202, MT700, MT760, MT940, camt.053, pacs.002) and showing call examples, which is valuable given there is no enum on the parameter.

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 and resource ('Look up SWIFT message types — MT (FIN) and MX (ISO 20022)') and immediately enumerates the domains covered, so an agent can distinguish it from siblings like swift_lookup or gpi_status_codes without opening the 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 gives both modes of use ('Pass a specific type to get full details, or omit to list all types') and adds a second legitimate use case (field-location questions). It does not, however, state when to prefer a sibling such as swift_lookup or gpi_status_codes instead, so no exclusion guidance is present.

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