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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds genuinely new behavioral context: page size bounds, the fact that the oldest returned message is not the conversation start when has_more is true, and the loop termination condition. It omits auth/permission or rate-limit notes, keeping it just short of 5.

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?

Four sentences, front-loaded with what the tool does and what it returns, then prerequisite, then pagination. Every sentence carries distinct operational information with no padding.

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 compensates by naming returned fields (text, timestamp, sender ID, read status, attachments) and fully specifying the pagination contract. An agent has everything needed to make a correct single call and to page correctly.

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 and the schema already documents chat_id, limit and cursor. The description goes beyond that by wiring cursor to next_cursor in an explicit multi-call loop, which clarifies intended usage of the parameter rather than restating it.

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 ('Get messages from a LinkedIn DM conversation') plus ordering ('newest first'), which cleanly distinguishes it from the sibling linkedin_list_conversations. An agent can tell exactly what this returns 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?

Gives the explicit prerequisite alternative ('Use linkedin_list_conversations first to get the chat_id') and a full when-to-repeat rule tied to has_more/next_cursor. Nothing about selecting or continuing this tool is left to inference.

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