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

The description discloses substantial behavior beyond the sparse annotations: duplicate persons are not re-created, repeat requests become notes on the open deal, and the Idempotency-Key header guards against double submission. This is exactly the kind of non-obvious behavior an agent needs, and it does not contradict the annotations.

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 sentences with no filler: the main action, the required contact condition, duplicate handling, and idempotency are each front-loaded in compact form.

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?

Despite 11 parameters and no output schema, the description omits parameter semantics for most fields and says nothing about the response shape. The duplicate/idempotency logic is valuable, but the tool is not fully specified for an agent to call it with confidence.

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?

With 0% schema description coverage and 11 parameters, the description must compensate, but it only explains the contact triad (email/phone/telegram) and the semantic requirement that at least one be present. It provides no meaning for course_id or the six UTM parameters, leaving most parameters semantically opaque.

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 uses a specific verb 'Завести' and defines the resource as a lead ('заявку') with a unique scope: creating a person and a deal in one request. This clearly distinguishes it from sibling creation tools like create_course or create_lesson, even without naming them.

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 establishes the key precondition that email, phone, or Telegram must be provided, and explains what happens with duplicate persons. It does not explicitly say 'use this instead of X' or list when not to use it, but the context is clear enough for an agent to select it for lead creation.

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