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

Annotations already establish read-only, non-destructive, closed-world behavior. The description adds valuable caveats: limit capped at 25 and unavailable legs are reported as not_seen or not_indexed rather than pending or failed.

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 resource and then covers lookup, filters, and index limitations with little waste. The middle sentence is dense and could be split, but overall it is appropriately sized.

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 output schema, the description still says what a message record includes: source and destination legs, apps, payload, Storeman group, and failed delivery attempts. All six optional parameters and the index limitation are covered.

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 0%, so the description carries the parameter burden and does so well: key can be a message id or any message transaction, chain accepts a captured chain key or XPort chain id, app is 0x hex, limit is up to 25, and cursor is mentioned.

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 resource, XPort (Wanchain Message Bridge) messages, and scopes it to OrbitWan's own index while enumerating what each record contains. It does not explicitly contrast itself with nearby cross-chain siblings such as get_address_crosschain or get_bridge_activity, so 4 rather than 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?

The description explains lookup behavior: key answers a specific message, otherwise newest-first with filters. That implies when to use it but gives no explicit when-not-to-use guidance or named alternatives among the many cross-chain/bridge siblings.

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