docs(mobile-phone-waterfall): add plan availability note (Launch+ required)

[george-dilthey]

What changed

Added a Plan availability note to docs/mobile-phone-waterfall.md stating that the Mobile Phone waterfall requires the Launch plan or above and is not available on the Free plan or during the free trial period.

Why

Intercom conversation #215475554762503 — a customer at an executive search firm (Ransom Group) asked how to find cell phone numbers for candidates. Fin incorrectly refused ("I'm sorry, but that's not something I'm able to help with under my policy"), triggering escalation. Human agent Aamish Samotra then provided two key answers:

1. The correct workflow: name + company → Enrich Person → resolve LinkedIn → Phone Number waterfall under Add enrichment > Phone Number > Waterfalls
2. "Phone number enrichment isn't included in the free trial or the Free plan. It unlocks on Launch and above."

The mobile-phone-waterfall.md doc had zero mention of plan availability. This means Fin had no way to answer "can I use phone enrichment on a free trial?" when retrieving content from that doc — it correctly describes the waterfall mechanics but was silent on who can access it. The building-a-data-waterfall.md covers trial plan restrictions for phone providers in its "Trial plan and provider restrictions" section, but the dedicated phone waterfall doc had nothing.

Source link(s)

• Intercom conversation: https://app.intercom.com/a/inbox/w28k1kwz/inbox/conversation/215475554762503
• Verifier sub-agent PASS: clay-base/libs/shared/src/billing/Billing.ts:92-93 — getNewBillingPlanGate(BillingFeatureCategoryType.PHONE_NUMBER) returns BillingPlanType.Launch; plan.ts:82-131 — Free and all Trial plan variants do not override EnablePhoneNumberIntegrations from its false default; plan.ts:160,182,228,249,270,291,318 — Launch and above all set EnablePhoneNumberIntegrations: true
• Slack: Stefan Kollenberg in #feedback-and-requests (Jan 2025): "all phone number integrations should be paid-plan only"; Clay Support bot in #support-testing (March 2026): "phone number enrichments are not included in the free plan"; #dust-support (Aug 2026): "Phone number enrichments are not available during the trial period"

Uncertainties

None. The claim is confirmed by code (plan-level feature flag, not an Eppo gate) and corroborated by multiple Slack messages and the human support agent's direct reply.

Related observations

• docs/find-people-overview.md and docs/finding-companies-and-people-in-clay.md both mention adding the phone waterfall as an enrichment step without noting the plan restriction. These are not contradictory (they don't say phone enrichment works on all plans), but adding a parenthetical plan note there could further help Fin. Out of scope for this PR.
• Fin initially refused to help the customer at all with finding phone numbers, apparently treating it as a policy violation rather than a legitimate enrichment question. This may be a Fin policy/training issue separate from the docs gap.

Closes DOC-2032

[linear-code]

DOC-2032