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Castles
Structured memory for LLMs, accessed via MCP
MCPFree tier
Audited by Jack Phillips · Updated June 2026
Overall score
2.8/ 5
SME fit4/5
flat pricing + free tier · technical setup
JTBD4/5
solid named JTBD
Integration3/5
MCP
Trust1/5
new (<12mo), founded 2025
Quality1/5
no public rating
Compliance2/5
compliance unknown
About
Castles is a structured knowledge base for teams whose workflows live inside Claude or other MCP-compatible clients. Workspaces are 'castles' containing 'rooms' with artifacts; an MCP server exposes search and retrieval tools so an agent can read the right document mid-conversation. Read-only, OAuth 2.1 + PKCE auth.
Best for: Teams already using Claude or another MCP client who want their internal knowledge accessible inside the chat — no copy-paste.
Pricing
Free
- Monthly
- Free
- Annual /mo
- Free
- Billing
- flat
- Notes
- MCP server access; castles / rooms / artifacts; OAuth or Bearer auth · Only publicly documented tier. Vendor states MCP is included on every plan including Free.
| Tier | Monthly | Annual /mo | Billing | Notes |
|---|---|---|---|---|
| Free | Free | Free | flat | MCP server access; castles / rooms / artifacts; OAuth or Bearer auth · Only publicly documented tier. Vendor states MCP is included on every plan including Free. |
Key features
- Streamable HTTP MCP server
- OAuth 2.1 with PKCE plus static Bearer tokens
- Castles / rooms / artifacts workspace model
- Full-text search across artifacts (search_artefacts)
- Tier-based access controls (internal / shared / public)
- Read-only retrieval (no writes from MCP)
Trust & compliance
- Stage range
- MVP → Growth
- Founded
- 2025
- Status
- active
- SOC 2
- unknown
- GDPR
- unknown
- Data residency
- us
- External rating
- n/a
- Last verified
- Jun 2026
Reviews
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