horizon_signup_emailCreate a new horizOn user account using email, password, and display name. Provide the required credentials to register a user and enable backend access in game and app projects.
Creates a new user account on horizOn with email and password.
| Name | Required | Description | Default |
|---|---|---|---|
| Yes | Email address (max 40 characters) | ||
| password | Yes | Password (4-32 characters) | |
| displayName | Yes | Display name (max 30 characters) |
Changes observed during successful MCP inspections.
v1.5.4Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden. 'Creates' flags a mutation, but nothing is said about duplicate-email handling, password policy enforcement, whether a session token is returned, or what a failure looks like.
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?
A single front-loaded sentence with no filler. It is efficient, though its brevity is partly the reason usage and behavior context are missing.
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 an unannotated account-creation mutation with no output schema, this one-liner leaves out error outcomes, session/return behavior, and signup-path routing. An agent could call it, but not confidently handle the result.
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 constraints (lengths, email pattern) are already documented. The description names email and password but omits displayName, a required parameter, so it adds no information beyond the schema baseline.
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?
States a specific verb and resource ('Creates a new user account') plus the credential mode ('with email and password'), which implicitly separates it from horizon_signup_anonymous. It stops short of explicitly naming that sibling, so an agent must still infer the routing.
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?
No when-to-use context, no prerequisites, and no mention of the sibling alternatives horizon_signup_anonymous or horizon_signin_email. The agent gets no guidance on which signup path to pick.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.