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

The description discloses multiple behavioral traits beyond the annotations: random delay, daily/hourly limits, allowed hours, human approval, and the DUPLICATE_RECENT_MESSAGE refusal code with campaign name and date. Annotations only indicate readOnly=false, so this is substantial added value that prepares the agent for real-world constraints.

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?

The description is three sentences with zero fluff. The purpose is front-loaded in the first sentence, the parameter preference and constraints in the second, and the error condition and alternative in the third. Every sentence earns its place and the structure is easy to scan.

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 send tool with no output schema, the description covers the essential context: when to use it, key constraints (limits, approval), how to avoid duplication errors, and the alternative for existing conversations. Nothing an agent needs to invoke it correctly is missing.

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 schema already documents all four parameters. However, the description adds semantic value by stating 'Prefer contact_id; Salesbot resolves the LinkedIn identifier internally,' which clarifies the relationship between contact_id and linkedin_id and gives a clear preference. This goes beyond simple field descriptions.

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?

The description opens with a specific verb and resource: 'Send a one-off LinkedIn message to a specific saved contact outside any campaign.' This clearly distinguishes it from campaign messaging and explicitly names reply_to_chat as the alternative for continuing conversations, so an agent can immediately tell when to use this tool versus its siblings.

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?

It explicitly states 'to continue an existing conversation use reply_to_chat,' giving a concrete alternative and the condition that selects it. The phrase 'outside any campaign' defines the intended scope, and the preference for contact_id over linkedin_id provides practical guidance on parameter selection.

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