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

Annotations already declare destructiveHint=true, idempotentHint=false, and openWorldHint=true, so the safety profile is covered. The description adds real behavioral value the annotations lack: new conversations return a chat_id for later replies, and InMail is available for non-connections. It doesn't warn about irreversibility or send-permission requirements, keeping it below 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?

Three tight sentences; the core action is front-loaded, followed by the two modes and the return-value note. No filler sentences.

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?

No output schema exists, and the description compensates by stating that a new conversation returns its chat_id. Combined with full schema coverage and annotations, an agent has enough to call it correctly; it could still note failure conditions (e.g. InMail limits or non-connection errors).

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 100%, so the schema already documents all five parameters including mutual exclusivity and the inmail/linkedin_api constraints. The description's parameter references mostly restate that, adding little beyond 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 splits the two supported modes: replying via chat_id vs starting a new conversation via recipient_identifier. This differentiates it from siblings like linkedin_send_connection_request and linkedin_comment_on_post.

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 which parameter path to use for each scenario and notes InMail applies only to non-connections, giving clear context for selection. It does not name alternative tools (e.g. when to prefer a connection request over an InMail), so it stops short of explicit alternatives/exclusions.

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