check_user_exists_by_email

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

The annotations already declare readOnlyHint=true, destructiveHint=false, and the description's phrasing ("Check whether... exists") implies a read-only operation without contradicting annotations. It adds no additional behavioral details like return format or error conditions, which is acceptable given the annotation coverage.

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 two concise sentences with no redundant wording. It front-loads the primary purpose and adds the workspace_id clarification without unnecessary detail.

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 existence-check tool, the description is complete: it states what the tool does and which parameter is needed. The return format is not mentioned, but since an output schema exists, that omission is mitigated.

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 schema coverage is 0%, but the description explains workspace_id as the target workspace ID with a pointer to list_workspaces(), and the 'email' parameter is explicitly referenced as the given email address. Both parameters receive sufficient semantic context, though email could be slightly more detailed.

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's purpose: checking whether a user account exists for a given email address. It uses a specific verb ('check') and resource ('user account'), distinguishing it from sibling tools like check_user_exists_by_phone or get_user.

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 includes a usage hint by explaining that workspace_id is the target workspace ID and directing users to list_workspaces() for obtaining valid IDs. It does not explicitly compare with alternative tools, but the name and description make the primary use case obvious.

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