referralhero_get_subscriberOne subscriber by id: contact data, referral code and link, points, position, referrals by level, status, fraud risk level, tags. Only verified subscribers are found. GET /lists/{uuid}/subscribers/{id}.
| Name | Required | Description | Default |
|---|---|---|---|
| uuid | Yes | Campaign (list) uuid, the 12-character id starting with MF (see referralhero_list_campaigns). | |
| subscriber_id | Yes | Subscriber id, e.g. sub_2bad325a25d7 (the id field of a subscriber). |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnlyHint true, destructiveHint false), and the description adds a genuinely useful behavioral constraint: 'Only verified subscribers are found', which tells the agent that unverified records will not be returned. It also discloses the shape of the returned payload, which matters given there is no output schema.
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 opens with the scoping ('One subscriber by id') before the payload enumeration, and the endpoint is appended as a compact identifier. The dense field list is information-bearing rather than padding, though it reads as a run-on.
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 output schema, the description compensates by enumerating the returned fields, and it flags the verified-only visibility rule that governs whether a lookup succeeds. What remains unstated is not-found error behavior and whether the returned referral tree is bounded, but the essentials for correct invocation are present.
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 coverage is 100%, with the uuid parameter documented as the 12-character MF campaign id and subscriber_id given an example format, so the schema carries the parameter semantics. The description adds nothing about the parameters beyond the endpoint path template.
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?
Names a specific verb+resource ('One subscriber by id') and immediately enumerates what the record contains (contact data, referral code/link, points, position, referrals by level, status, fraud risk level, tags). The 'by id' qualifier cleanly separates it from siblings get_subscriber_by_email, get_subscriber_by_referral_code and list_subscribers.
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?
Usage is implied through the 'by id' scoping and the endpoint, so an agent can infer it should pick this over the email/referral-code variants when it holds an id. However, there is no explicit statement of when to use this versus the lookup-by-email/referral-code siblings, or what to do when the id is unknown.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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