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

With no annotations provided, the description fully discloses behavior: how identity is resolved (business_guid claim first, email otherwise via identity_resolve), the guest-trial flag and associated fields, and the specific error case with the exact 401 code and required action. This goes well beyond a basic tool description and covers edge cases.

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 multi-paragraph but every sentence carries necessary information: the core purpose, resolution mechanism, guest-trial instructions, and error handling. It is front-loaded with the primary purpose and then provides detailed behavioral rules. While it is longer than average, the complexity of the guest-trial logic justifies the length. It could be slightly tighter, but it is not verbose.

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?

Even though an output schema exists, the description already explains the return fields (email, business_guid, plan, is_guest) and adds valuable context about guest trial and error handling. It covers all necessary scenarios an agent would need to handle when invoking this tool, including when to surface claim_url and how to react to the specific 401 error. Nothing essential 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?

The tool has zero parameters and the schema is empty, so there is nothing to add. The baseline for 0 parameters is 4. The description focuses on output and behavior rather than inputs, which is appropriate here.

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?

Clearly states the tool returns the caller's account with specific fields (email, business_guid, plan, guest status). The verb 'Return' and the resource are explicit, and it distinguishes itself from all sibling tools that deal with site/domain operations. The mention of 'Phase 0 end-to-end gate' adds context.

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 gives clear context about when the tool is used (as an identity gate) and what to do with the results (e.g., guest trial handling). It doesn't explicitly name alternatives, but there are no obvious sibling tools for identity resolution, so it's clear enough. The guest-trial instructions effectively say when to give claim_url vs not, which is a form of usage guidance.

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