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

The description goes beyond the annotations by warning that sent messages cannot be recalled and that the normal notification, webhook, and broadcast pipeline will run. This makes side effects and irreversibility explicit.

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 compact and well-structured: three sentences cover purpose, requirements, defaults, side effects, and irreversibility without unnecessary filler or repetition.

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 simple write tool with no output schema and no nested objects, the description includes the necessary purpose, inputs, defaults, and side effects. It does not address error conditions or return behavior, but these are not critical given the tool's simplicity.

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?

The schema already covers all four parameters with descriptions, and the tool description adds meaningful context around order_number, message, and staff_only behavior. It does not add validation details, but the provided semantics are sufficient for basic usage.

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 clearly states the action: 'Post a message to an order.' It identifies the resource, the operation, and the required inputs, leaving no ambiguity about the tool's primary purpose.

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 provides practical usage details such as requiring order_number and message, the staff_only default, and the client-notification behavior when set to false. It does not explicitly contrast with read-only alternatives, but the write-oriented purpose is clear enough.

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