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

Annotations already declare it as read-only, idempotent, and non-destructive, so the safety profile is fully covered. The description adds the notion of it being a connectivity check, which is a useful behavioral hint beyond the annotations. However, it doesn't mention potential failure modes or response format, but with annotations this is acceptable.

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, concise sentence that front-loads the main purpose and then specifies the fields. Every word earns its place, and it avoids redundancy. It's appropriately sized for a no-parameter tool.

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?

Given the tool has no parameters, no output schema, and annotations that cover safety, the description is complete enough. It explains what the tool does and when to use it. The only minor gap is not explicitly stating the return type, but the field list suffices for agent expectations.

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 tool has zero parameters, so the schema provides minimal information. The description adds semantic value by enumerating what fields will be returned (name, email, avail_cents, etc.), which helps the agent understand what to expect from the response, even though it's not a parameter explanation. This compensates for the lack of parameter documentation.

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 clearly states the tool returns the signed-in creator's identity details (name, email, balance fields). This is a specific verb-resource pairing ('who am i') that distinguishes it from siblings like split_get_profile and split_get_settings, which are more general or focused on other data.

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 mentions it's useful as a connectivity check and for balance questions, giving concrete usage scenarios. It doesn't explicitly name alternatives, but given the context, it implies when to use this instead of other getters. This is sufficient guidance for an agent.

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