horizon_signin_anonymousAuthenticates an anonymous user on horizOn using a provided anonymous token of up to 32 characters, returning a signed-in session for backend access.
Signs in an anonymous user on horizOn using their anonymous token.
| Name | Required | Description | Default |
|---|---|---|---|
| anonymousToken | Yes | Anonymous token (max 32 characters) |
Changes observed during successful MCP inspections.
v1.5.4Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full behavioral burden but discloses almost nothing beyond the mechanics. It does not say whether this establishes a persistent session, what happens on an invalid/expired token, or whether the operation has side effects, which is important for an auth operation.
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 compact sentence with the action front-loaded and no filler. It is appropriately sized, though the brevity is also the source of the missing guidance.
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 auth entry point with no annotations and no output schema, the description should explain the token's origin, the resulting session state, and failure behavior. None of that is present, leaving the agent unable to reason about post-conditions.
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%, and the single anonymousToken parameter is fully documented in the schema including its max length. The description merely restates the token's role, so baseline 3 applies.
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 (signs in) and resource (anonymous user) with the mechanism (anonymous token). However, it does not distinguish itself from the sibling horizon_signup_anonymous, which is the closest alternative and the likely source of the token, so sibling differentiation is left to inference.
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 guidance is offered. It never states the prerequisite that an anonymous token must first be obtained via horizon_signup_anonymous, nor when an agent should prefer this over horizon_signin_email or horizon_check_auth.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.