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

With no annotations, the description carries the full burden and does disclose the most important trait: it sends nothing, it only shows recipient, subject and body as they would be sent. It does not mention whether the lead must exist, whether validation errors are raised, or any permission requirements, but the critical safety profile is stated clearly.

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, front-loaded with the dry-run framing and ending with the imperative workflow rule. No filler.

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?

There is no output schema, but the description compensates by saying the preview shows recipient, subject and body exactly as they would be sent. Combined with the safety statement, an agent has everything needed to call and interpret this 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 description coverage is 75% and the schema already documents id, to (with its default) and body. The description only restates that recipient, subject and body are echoed, adding little beyond the schema and nothing about the one undescribed parameter (subject). Baseline 3 is appropriate.

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 (dry-run preview of an email to a lead) and explicitly frames it as the non-sending counterpart to crm_send_email_to_lead. An agent can distinguish it from the send tool and from the many other preview_* siblings without opening the schema.

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?

Gives an explicit directive — 'ALWAYS call first and show the draft to the human' — plus the alternative it precedes (crm_send_email_to_lead). The when-to-use condition is unambiguous and even encodes the required human-in-the-loop step.

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