List messages

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds the non-obvious ordering fact ('newest first') and that both sent and received are returned, but says nothing about pagination limits or result volume beyond what the cursor/limit schema already implies.

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?

Two compact sentences with the resource and ordering front-loaded, and the sibling pointer last. Slight awkwardness in the opening ('Messages wuapi stored') but no filler or redundancy.

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 paginated read-only list tool whose annotations carry the safety profile and whose schema covers 83% of parameters, the description says enough to call it correctly. Only return-shape/pagination expectations beyond the cursor field are left implicit.

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 description coverage is 83% (above the 80% threshold), so the baseline is 3. The description echoes three filter dimensions (account, chat, direction) that the schema already documents, and adds no syntax or format detail for limit, cursor, or projectId.

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+resource ('Messages ... stored') with scope ('newest first: sent and received'), and names a sibling (list_chats) to clarify what it is not. It stops short of distinguishing itself from get_message, but an agent can still tell the general purpose 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?

'Filter by account, chat and direction to read a conversation' gives a clear use context, and 'Use list_chats to see which conversations an account has' points to the prerequisite/alternative source of chat ids. There is no explicit when-not guidance, so it falls short of a 5.

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