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

Annotations cover the safety flags (readOnlyHint=false, idempotentHint=false, openWorldHint=true), but the description adds material context beyond them: the message reaches a real person, it cannot be unsent, and the preview-then-confirm safeguard. This is genuinely useful disclosure for an irreversible action.

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?

Four short sentences, front-loaded with the single-contact scope and the irreversibility warning, then the workflow. Every sentence earns its place; nothing is 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?

With no output schema, the description explicitly notes the preview shows 'exactly who would receive what,' covering the return behavior. For a mutation tool it supplies the safety, workflow, and scope details an agent needs to invoke it correctly.

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 67% and the schema already documents confirm, contact_id, subject, and message. The description reinforces the confirm workflow but adds little parameter syntax/format detail beyond what the schema provides, so the 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 with explicit scope: 'Send ONE email or SMS to ONE existing HighLevel contact.' It also negates the bulk case ('There is no bulk send'), which clearly separates it from the many sibling tools like highlevel_read_conversation and highlevel_conversations.

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 two-step workflow: call first WITHOUT confirm to preview, show the human, then call again with confirm: true. It names the condition that selects the confirm path and rules out bulk sending, leaving nothing to inference.

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