Cairn
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Simple plans, one shared principle

Knowledge shared with the community stays free.

Free

For exploring, contributing, and building your first Cairns.

US$0forever
  • Read public Cairns and contribute, without limits
  • Own 3 private and 3 team collections
  • 50 AI asks a day, MCP included
Start free →

Pro

Founding offer

For people who rely on Cairn as private working memory.

US$7.50per monthSave 17%

US$90 billed once a year.

  • Unlimited private and team collections
  • 200 AI asks a day, 5× the filing allowance
  • 1 Moss Care pass a week for your default collection
Get Pro →

Team

Team onboarding

Help your team's agents understand the shared background and decisions. Tell us about your collaboration workflow, usage scale, and adoption needs.

  • Your collaboration workflow
  • Existing knowledge and context
  • Adoption needs and usage scale
Talk with us· [email protected] →

Keep this founding price while your subscription stays active. The planned price for new members is US$18 per month.

Monthly or annual billing. Cancel any time. Taxes may apply.

Plan comparison

See exactly what changes with Pro

Both plans include the complete Cairn loop. Pro adds room and AI capacity for people who depend on it every day.

Read public Cairns
FreeUnlimitedProUnlimited
Contribute to communities
FreeIncludedProIncluded
MCP agent access
FreeIncludedProIncluded
Owned private and team collections
Free3 + 3ProUnlimited
AI asks
Free50 per dayPro200 per day
Moss Care
FreePreview and past reportsPro1 pass each week for your default collection
AI-assisted filing and gap finding
FreeStandard capacityPro5× daily capacity

Pay for private leverage, not a louder public voice.

Pro never raises a card's rank, changes its provenance, or buys moderation power. Public reading and community contribution remain part of the commons.

Questions

Before you choose

What am I actually paying for?

Pro removes owned-collection limits, raises every model-backed allowance, and lets you run 1 Moss Care pass each week for your default collection. Moss finds knowledge that may be stale or missing and leaves proposals; you still decide what changes.

Do I need Pro to use Cairn with an agent?

No. MCP access is included on Free because an agent-readable memory is part of the core product. Pro gives frequent users more capacity.

What happens if I cancel?

You return to Free at the end of the billing period. Your content is not deleted; Free limits apply again, so you may need to reduce usage before creating more collections.

Why keep community contribution free?

Cairn becomes more useful when hard-won knowledge can compound. We charge for private leverage and ongoing AI work, not for helping a community remember.