start_login

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

With no annotations, the description carries the behavioral burden. It discloses that the code is delivered out of band (email, SMS, or flash call), implying the agent must await user input. It also implies the operation is non-destructive by nature of being a login initiation. However, it does not mention potential errors, rate limits, or idempotency, which would strengthen transparency further.

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?

Two sentences, front-loaded with the purpose, then the usage condition and next step. No filler; every sentence earns its place.

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?

The tool is part of a login flow with session_status and submit_login_code. The description covers when to use, what it does, and what to do next. An output schema exists to describe the return value, so nothing critical is missing for an agent to call 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?

The schema already covers the parameter fully: 'The account's email or phone, as registered with Ozon.' The description repeats this ('account email or phone') without adding new syntax or format details, so it adds no value beyond the schema. With 100% coverage, 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?

The description states a specific verb and resource: 'Ask Ozon to send a one-time login code to `login`'. It clearly distinguishes this from sibling tools like submit_login_code (which submits the code) and session_status (which checks status), so an agent can tell them apart without reading schemas.

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 explicitly gives the condition for use: 'Use this when session_status() reports signed_in=false and the kept profile copy did not recover it.' It also instructs the agent to ask the user for the code and pass it to submit_login_code(), providing clear routing to the next step.

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