diff --git a/SPEC.md b/SPEC.md
new file mode 100644
index 0000000..2e4c684
--- /dev/null
+++ b/SPEC.md
@@ -0,0 +1,47 @@
+# BTCPay Server Plugin: Event & Travel Integration (V1)
+
+## 1. Data Sources & Verification
+- Event data: Curated from hardcap.news RSS/API feed (events aggregated by Cayce runtime §9). Source list documented in `sources/` directory with QC-3 citations.
+- Lodging data: `bitcoinhotels.org` static listings API. No real-time availability checking in V1 - listings are curated, not live.
+- Verification: Event dates/coords verified against hardcap.news primary sources only. No automated scraping of third-party calendars.
+
+## 2. Booking & Payment, Sellers & Refunds
+- Booking: Plugin displays curated BTC-friendly hotel/merchant listings with deep links to `bitcoinhotels.org`. Reservation/payment occurs off-site via the hotel's own system.
+- Seller: Individual hotels/merchants own their availability and booking terms. The plugin has no inventory control.
+- Refunds: Responsibility of the hotel/merchant, not the plugin or organizer. Plugin displays refund policy links where provided by the hotel.
+- Payment processing: BTCPay Server handles event ticket/registration payments (sats only). No hotel payments flow through BTCPay in V1.
+
+## 3. BTCPay Server Plugin API Capabilities (official sources)
+- Event feed ingestion: Plugin reads hardcap.news event RSS feed (curated by Cayce). Auto-generates event landing pages on bitcoinhotels.org.
+- Geolocation filtering: Hotel listings filtered by proximity to event venue coordinates (lat/lon).
+- BTCPay payment integration: Accept sats for event registrations via BTCPay Server's payment API. Plugin creates order → attendee pays → organizer receives notification.
+- Blink Donate Button: Embedded for voluntary zaps to support ongoing curation.
+- Limited V1 scope: RSS feed ingestion & template generation; Geolocation-based filtering; BTCPay payment acceptance for event tickets; Static Blink button embed; NO real-time availability checking; NO hotel inventory management; NO automated refund processing.
+
+## 4. Privacy: Data Requests & Storage
+- Data requested: Event title, dates, venue coordinates (lat/lon), hotel merchant name, brief description, deep link URL.
+- Data storage: Event coords stored in plugin's `data/events.json` (plain text, no personal data); Merchant names and URLs stored as provided by bitcoinhotels.org; NO IP addresses, NO user identifiers, NO location data beyond event venue coords.
+- Privacy rule: No "zero KYC" claims without substantiation. All data is publicly derivable from the event and hotel listings. No user tracking.
+
+## 5. What Each Party Gains (no marketing language)
+- Event organizers: Turnkey way to surface BTC-friendly lodging within event checkout. No platform fees. BTC-only payments expand circular economy.
+- Attendees: Find BTC-friendly lodging without leaving event checkout. Pay with sats. Merchant choices are curated (no altcoin-promoting hotels).
+- Hotel merchants: Exposure to Bitcoin-targeted audience. No platform fees for listing. Direct booking relationship.
+- Cayce/bitcoinhotels: Continuous curation output. Plugin is open-source under MIT license. Long-term sustainability via hardcap.news adinaction and Nostr zap-gating.
+
+## 6. V1 Minimal Scope
+- Plugin scaffold with MIT license
+- RSS feed ingestion from hardcap.news (events list)
+- Landing page template on bitcoinhotels.org (event-specific)
+- Geolocation filter: proximity within 50km of event venue
+- BTCPay payment acceptance for single-price event tickets
+- Blink Donate Button embed
+- Documentation: installation, API config, admin options
+- NO availability checking, NO real-time booking, NO refund handling, NO altcoin support
+
+## Appendix: Official Sources
+- BTCPay Server Plugin Development Guide: docs.btcpayserver.org/developer/plugins
+- BTCPay Server API docs: docs.btcpayserver.org/api
+- BTCPay Server payment flow: server-specific, involves order creation → payment link → webhook notification
+- hardcap.news event curation methodology: QC-3 sourced, daily digest process
+- bitcoinhotels.org listing format: static CSV/JSON, merchant-owned availability
diff --git a/docs/cayce-dev.md b/docs/cayce-dev.md
new file mode 100644
index 0000000..b57c581
--- /dev/null
+++ b/docs/cayce-dev.md
@@ -0,0 +1,48 @@
+# cayce-dev Design Document
+
+*Authorized by operator merge to main. This design governs the cayce-dev sandbox.*
+
+## Flow
+- Cayce opens a PR with SPEC.md on a product repo. Operator's merge to main = authorization.
+- cayce-dev only takes specs already merged by the operator. Implements on a branch and opens a PR. Operator merges.
+- If the spec is ambiguous, ask in the PR; do not improvise.
+
+## Gitea Access
+- Token limited to product repos (branches and PRs only).
+- No merge access, no admin access, no access to cayce-ops or hardcap.
+- Commit author: cayce-dev.
+- Workflow: operator reviews SPEC.md PR → merges → cayce-dev creates feature branch → opens PR → operator merges.
+
+## Isolation
+- Own container or user. NO access to:
+  - nsec (operator key or agent identity)
+  - .env files (operator keys, API tokens, database credentials)
+  - Production database
+  - Tokens (sfeed, Facebook, Instagram, Mail, SSH)
+  - Docker socket or any container orchestration API
+  - Operator keys or agent identities
+- Network: only local Gitea and package registries. No outbound capability beyond.
+- No deploy or publish capability.
+
+## How Each Restriction Will Be Tested
+- Container isolation: verify cayce-dev user cannot read /srv/cayce-core/.env or /home/ubuntu/.sfeed/tokens.json
+- Network: verify cayce-dev container has no internet access beyond Gitea
+- Key access: verify no Cayce nsec or operator pubkey is exposed to the sandbox
+- Auth token access: verify no operator tokens are readable
+
+## Execution
+- Model/runtime options with pros/cons (operator decides):
+  - Local LLM (private, no cost per token, limited capability)
+  - Remote API (cost per token, broader capability, privacy tradeoff)
+  - Sandboxed execution environment
+- Time/iteration/cost limits per task (operator-defined):
+  - Max 3 iterations per task
+  - Max 15 minutes per iteration
+  - Max $0.10 USD per task (using cheapest available model)
+- Mandatory tests in sandbox: every implementation must have corresponding tests within the sandbox environment
+- Execution log without secrets: every execution step must be logged without exposing secrets, API keys, or private data
+
+## Report
+- Summary in the cycle DM toward the operator
+- Include: what was executed, outcomes, any restrictions encountered, compliance status
+