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

Beyond the destructiveHint annotation, the description discloses the concrete effect: the chatbot stops sending on the next page open, and past message-log entries are retained. That tells the agent what is actually lost vs preserved, which annotations cannot express.

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, each carrying distinct information: the operation, the runtime effect plus retention behavior, and the non-destructive alternative. Front-loaded and free of 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?

For a two-parameter destructive delete with full schema coverage and no output schema, the description covers effect, data retention, and alternatives. It stops short of stating failure behavior (e.g., nonexistent rule_id) or whether the deletion is reversible, which would make it fully complete.

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%, and the schema already explains rule_id sourcing from list_proactive_messages and website_id fallback behavior. The description adds no syntax or format detail beyond that, so the baseline 3 applies.

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 ("Delete one Proactive Messages rule") and immediately follows with the observable consequence, so the agent knows exactly what changes. It is clearly distinguishable from siblings like list_proactive_messages and save_proactive_message.

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?

Names the alternative explicitly ("To pause a rule instead, use save_proactive_message with enabled false") and gives the condition that selects it, which is the most common confusion point for a delete tool. Nothing 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.