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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the core side effect (an email is sent) but discloses nothing else: no mention that OTPs expire, that sending may be rate-limited, that a previous OTP may be invalidated, or that this step does not itself authenticate the user.

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 a single tight sentence with no wasted words and the core action front-loaded. It is appropriately lean for a one-parameter tool, though it errs slightly toward under-specification rather than optimal sizing since a second sentence about the follow-up verify step would add high value without bloat.

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?

Complexity is low (one required parameter, no nested objects), but the surrounding structured context is also thin: no annotations and no output schema. The description leaves the agent without essential flow context — there is no indication that authentication is a two-step process, no mention of what the tool returns (request ID, status, etc.), and no error conditions described. For a tool named auth_start, this is a meaningful gap.

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%, so the schema already documents the email parameter as 'Login email'. The description adds marginal meaning by clarifying that the OTP is delivered to this address, but this is largely redundant with the tool's own purpose. Baseline 3 is appropriate given the schema carries the heavy lifting.

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 has a specific verb ('Send'), a clear resource ('an OTP'), and a destination ('to an email address'). It clearly states the action. However, it does not differentiate itself from the closely related sibling commsharbor_auth_verify, and it never mentions that this is the first step of a two-step authentication flow.

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?

There is no guidance about when to use this tool. It does not state that this initiates an auth flow that must be completed via commsharbor_auth_verify, does not mention prerequisites (e.g., whether the email must belong to an existing user), and gives no hints about when this is or isn't the right tool relative to its siblings.

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