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

Annotations only declare destructiveHint=true; the description goes well beyond that by disclosing the side effect on any pending scheduled call, the all-or-nothing atomicity ('Nothing is deleted unless every lead is found'), the 100-item cap, and the confirmation requirement. These are the exact behavioral facts an agent needs before invoking a destructive tool.

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, front-loaded with the action and scope, then the side effect, then the guardrail. No filler or redundancy.

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 destructive batch tool with no output schema and full schema coverage, the description supplies everything else needed: cascade effect, atomicity semantics, batch limit, and a user-confirmation requirement. Nothing material 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 description coverage is 100%, so the properties already document lead_id, lead_ids, and phone_number, including the 100-item limit. The description restates the one-of selection model but adds no format, syntax, or precedence detail beyond the schema. 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 ('Delete a lead'), and immediately quantifies scope ('or up to 100 leads at once'), which distinguishes it from sibling update_lead, get_lead, and delete_note. The cascade behavior is also named up front.

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 clear triggering conditions: use one identifier (lead_id or phone_number) for a single lead, or lead_ids for a batch, and explicitly instructs 'Confirm with the user first.' It does not name sibling alternatives (e.g., delete_number_item or update_lead) or state when not to use it, so it falls short of a 5.

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