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

Annotations already cover the safety profile (readOnly, non-destructive, openWorld). The description adds ordering (newest first), the fact that each message carries its conversation id, and an explicit prompt-injection warning that message/post text is authored by others and must be treated as data — real behavioral context beyond the annotations.

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?

Compact and information-dense: the bracketed id-in/id-out notation is terse but useful, and the prose sentence leads with the operation and scope. Slightly unorthodox formatting (id notation ahead of the purpose sentence) costs a point on front-loading.

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 responsibly covers the return shape via the id-out mapping and ordering, and the cursor parameter is documented in the schema for pagination. An agent has enough to call it correctly, though filtering and pagination behavior could be spelled out further.

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%, so the baseline is 3, but the description adds provenance the schema lacks: senderId is an attendee id obtained from list_chat_attendees → attendees[].id, which the schema only calls 'this participant id.' It also maps outgoing ids (message, chat, sender attendee, member, attachment).

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, plus scope: 'Read your LinkedIn messages across ALL conversations, newest first.' The 'ALL conversations' scope implicitly separates it from per-chat siblings like list_chat_messages and list_attendee_messages, but no sibling is named explicitly.

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?

Provides one concrete use case ('what came in since yesterday') and the after/before parameters support it. However it never states when to prefer it over get_message, list_chat_messages, list_attendee_messages, or list_inmail, so the agent must infer routing from scope alone.

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