Start Telegram login

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

The annotations already mark this as non-read-only and open-world. The description adds important behavior: Telegram sends a login code to the account and the flow continues through auth_code and auth_password when 2FA is enabled. It does not cover failure cases, rate limits, or session side effects, but it provides strong workflow context beyond 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?

The description is short, front-loaded with the action, and every sentence contributes either the side effect or the required follow-up calls. There is no unnecessary wording.

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 login-start tool with annotations and a fully documented single parameter, the description covers the essential action, side effect, and next steps. Because no output schema exists, it could say more about what auth_start returns, but the workflow guidance is otherwise complete.

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%, and the single phoneNumber parameter is fully documented in the schema with an international format example. The description only refers to 'phone-number login' and adds no format or validation detail beyond the schema, so the baseline score of 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 uses a specific verb and resource: 'Start phone-number login.' It also distinguishes this step from the sibling tools auth_code and auth_password by explaining the sequence.

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 states when to use this tool and names the follow-up tools: call auth_code after receiving the code, and auth_password if two-step verification is enabled. This gives clear sequencing with no ambiguity about the next step.

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