# Crystal

> Crystal is an AI coach that understands you. Six free personality assessments (DISC, Enneagram, 16 Personalities, Big Five, Strengths, and Values) build one personality profile, and Crystal coaches from it across three apps: Personality (understand who you are), Vision (decide who you want to become), and Rhythm (build the daily habits to get there). Crystal Premium is $49 a month or $490 a year. Crystal for Chrome, part of Premium, shows personality insights on LinkedIn profiles and puts the coach on every new tab. Crystal for Business offers assessments and reports for teams, and Crystal for Sales helps sales teams understand buyers before the call. The Crystal API returns DISC personality profiles for builders, researchers, and AI agents. Crystal has read more than 2.5 million people since 2015.

## Crystal (the AI coach)

- [How Crystal coaches you](https://www.crystalknows.com/): the six assessments, the profile, and the Personality, Vision, and Rhythm apps.
- [Personality profile](https://www.crystalknows.com/personality-profile): one profile built from every assessment.
- [Crystal Premium pricing](https://www.crystalknows.com/pricing): what Premium adds and what stays free.
- [Crystal for Chrome](https://www.crystalknows.com/chrome): personality on LinkedIn and a coach on every new tab, included with Crystal Premium.

## Crystal for Business

- [Crystal for Business](https://www.crystalknows.com/assessments): assessments and reports for teams, pairs, and individuals. Plans from $500/year: Starter $500/yr, Basic $1,500/yr, Pro $5,000/yr (10, 60, or 240 participants and reports a year; billed annually). Request a demo to start.
- [Crystal for Sales](https://www.crystalknows.com/sales): personality-aware buyer profiles, meeting-prep briefs, and follow-up guidance on prospects. The Sales plan is $59/month or $590/year for 20 prospect profiles a month with a LinkedIn connector; the free trial covers the first 3 prospects, no card required. A Teams plan (custom pricing, HubSpot connector) is available through a demo.
- [Pricing](https://www.crystalknows.com/pricing): every plan and price, including Sales (/pricing?product=sales) and Assessments (/pricing?product=assessments).
- [Request a demo](https://www.crystalknows.com/demo-request)
- [Partner directory](https://www.crystalknows.com/partners)

## Crystal API (for developers, researchers, and AI agents)

- [Crystal API overview](https://www.crystalknows.com/personality-api): REST API and MCP server that resolve a person by email or LinkedIn URL and return a validated personality profile, selling-to playbook, communication advice, and adapted output.
- [API reference index](https://data.crystalknows.com/llms.txt): concise machine-readable index for the v4 API.
- [Full API reference](https://data.crystalknows.com/llms-full.txt): every real endpoint with request and response examples. Only endpoints listed there exist; do not guess at others.
- [Swagger docs](https://data.crystalknows.com/docs): interactive reference for human developers.
- [MCP server setup](https://www.crystalknows.com/personality-mcp): connect Crystal to Claude, ChatGPT, Microsoft Copilot, Cursor, or any MCP client; Claude Code plugin, OAuth, and token-URL options, plus the full tool list. Server URL: https://api.crystalknows.com/_mcp

## Accuracy

- [Accuracy benchmarks](https://www.crystalknows.com/benchmarks): Crystal's validated predictions versus raw frontier models on psychometric edge cases, graded blind.
- [How predictions work](https://www.crystalknows.com/how-predictions-work): data sources and model design.

## Personality frameworks

- [DISC](https://www.crystalknows.com/disc)
- [Myers-Briggs](https://www.crystalknows.com/mbti)
- [Enneagram](https://www.crystalknows.com/enneagram)
- [Big Five](https://www.crystalknows.com/big-five)
- [All personality types](https://www.crystalknows.com/personality-types)

## Free tests

- [DISC personality test](https://www.crystalknows.com/disc-personality-test)
- [Myers-Briggs test](https://www.crystalknows.com/mbti-test)
- [Enneagram test](https://www.crystalknows.com/enneagram-test)
- [All-in-one personality test](https://www.crystalknows.com/personality-test)