horizon_validate_gift_codeChecks whether a gift code is valid for a specific user on horizOn before redemption, without consuming or redeeming it.
Validates a gift code on horizOn without redeeming it. Checks if the code is valid for the given user.
| Name | Required | Description | Default |
|---|---|---|---|
| code | Yes | Gift code to validate (max 50 characters) | |
| userId | Yes | User ID (UUID) |
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 burden. It usefully discloses that the operation is non-mutating ('without redeeming it'), but says nothing about what an invalid code yields, error behavior, auth requirements, or rate limits for a 2-required-param live service call.
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?
Two short sentences with the non-redemption constraint front-loaded in the first; every clause earns its place and nothing is padded.
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?
With no annotations and no output schema, the description should at least hint at the return shape (boolean validity vs. error object) for a validation call. It covers purpose well but leaves the response contract entirely unspecified.
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%, with both code (max 50 chars) and userId (UUID) documented in the schema, so the baseline is 3. The description only adds that validity is evaluated 'for the given user,' a marginal clarification over the schema.
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 (validates), resource (gift code), and scope. The clause 'without redeeming it' directly distinguishes it from the sibling horizon_redeem_gift_code, so an agent can route between the two without opening either schema.
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 a clear use context (checking validity of a code for a user) and implicitly separates it from redemption, but it never names the alternative tool or states when a check is preferable to just redeeming.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.