login_start

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

With no annotations, the description carries the behavioral burden, and it does disclose the key side effect: an SMS is sent to the user's phone. It also reveals the stateful handoff via sessionId. It could add error or rate-limit caveats, but the core behavior is transparent.

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 short sentences with no filler. The primary action is front-loaded, and the required follow-up with login_complete is stated in sequence.

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 simple one-parameter tool with no output schema, the description covers what happens, what is returned, and the next call to make. Nothing needed for correct invocation 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 0%, but the description compensates by identifying the parameter as an Iranian mobile number and indicating it receives the SMS code. Combined with the regex pattern in the schema, the agent has enough semantic meaning to supply the correct value.

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 names a specific action ('Start Sheypoor login'), the mechanism ('sends an SMS code'), and the return contract ('returns a sessionId'). It clearly distinguishes login_start from the sibling login_complete by defining this as the initiating step.

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?

The description explicitly instructs that the returned sessionId must be passed to login_complete along with the user's code. This tells the agent when to use this tool and what to do next, effectively differentiating it from the completion step without ambiguity.

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