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

Annotations already declare it is a non-idempotent, open-world write (readOnlyHint=false, idempotentHint=false), so the safety profile is covered. The description adds genuinely useful behavior: InMail works for non-connections, and a new conversation returns a chat_id for later replies. Permissions and rate-limit behavior are unstated.

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?

Three short sentences, the core action front-loaded, and the return-value note placed last. Every sentence carries distinct 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 usefully discloses that a new conversation yields a chat_id. It covers the main call paths, though it omits permission requirements or error behavior for a write tool.

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 meaning beyond the schema by framing chat_id and recipient_identifier as a reply-vs-new-conversation choice and tying InMail to the recipient path. It restates the mutual exclusivity the schema already documents, so it does not fully exceed the baseline.

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 ('Send a LinkedIn message') and immediately branches into the two modes of operation (reply vs. new conversation), plus the InMail capability. No sibling tool sends messages, so the scope is unambiguous.

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?

Explains the two entry paths clearly: use chat_id to reply, recipient_identifier to start new, and InMail only for non-connections. It stops short of naming when to prefer this over e.g. linkedin_send_connection_request, but the in-tool routing is explicit.

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