diff --git a/docs/EVIDENCE-ARCHITECTURE.md b/docs/EVIDENCE-ARCHITECTURE.md
index b98042a..f181978 100644
--- a/docs/EVIDENCE-ARCHITECTURE.md
+++ b/docs/EVIDENCE-ARCHITECTURE.md
@@ -29,11 +29,13 @@ Different domains have different platforms:
 | Protocol | Ponder / GraphQL | On-chain state, trades, positions | **Partial** — Live (not yet wired to evidence) |
 | Infrastructure | DigitalOcean / system stats | CPU, RAM, disk, containers | **Planned** — Supervisor monitors, no evidence output yet |
 | User experience | Playwright personas | Conversion, friction, journey completion | **Partial** — Scripts exist (`run-usertest.sh`), no evidence output yet |
+| Engagement | Caddy access logs | Visitors, referral sources, page paths | **Implemented** — `site/collect-engagement.sh` |
 | Funnel | Analytics (future) | Bounce rate, conversion, retention | **Planned** — Not started |
 
 Agents won't need to understand each platform. **Processes act as adapters** — they will read a platform's API and write structured evidence to git.
 
 ```
+[Caddy logs]      ──→ collect-engagement process ──→ evidence/engagement/YYYY-MM-DD.json
 [Google Analytics] ──→ measure-funnel process ──→ evidence/funnel/YYYY-MM-DD.json
 [Ponder GraphQL]  ──→ measure-protocol process ──→ evidence/protocol/YYYY-MM-DD.json
 [System stats]    ──→ measure-resources process ──→ evidence/resources/YYYY-MM-DD.json
@@ -56,6 +58,7 @@ Produce evidence without modifying the project under test. Some sense processes
 | `run-user-test` | UX quality across 5 personas | Playwright + docker stack | Spawns Docker stack (containers + volumes + networks); requires Docker daemon; leaves ephemeral state until torn down | **Implemented** — `run-usertest.sh` exists (harb #978) |
 | `measure-resources` | Infra state (CPU, RAM, disk, containers) | System / DigitalOcean API | Read-only API calls. Safe to run anytime | **Planned** |
 | `measure-protocol` | On-chain health (floor, reserves, volume) | Ponder GraphQL | Read-only API calls. Safe to run anytime | **Planned** |
+| `collect-engagement` | Visitor engagement (visitors, referrers, pages) | Caddy access logs | Read-only log parsing. Safe to run anytime | **Implemented** — `site/collect-engagement.sh` (disinto #718) |
 | `measure-funnel` | User conversion and retention | Analytics API | Read-only API calls. Safe to run anytime | **Planned** |
 
 ### Mutation processes (create change)
@@ -86,6 +89,7 @@ The planner won't need to know this loop exists as a rule. It will emerge from e
 
 ```
 evidence/
+  engagement/       # Visitor counts, referrers, page paths (from Caddy logs)
   evolution/        # Run params, generation stats, best fitness, champion
   red-team/         # Per-attack results, floor held/broken, ETH extracted
   holdout/          # Per-scenario pass/fail, gate decision
diff --git a/docs/OBSERVABLE-DEPLOY.md b/docs/OBSERVABLE-DEPLOY.md
new file mode 100644
index 0000000..3f5e618
--- /dev/null
+++ b/docs/OBSERVABLE-DEPLOY.md
@@ -0,0 +1,88 @@
+# Observable Deploy Pattern
+
+> Every addressable is born observable. It's not shipped until it's measured.
+> — VISION.md
+
+## The pattern
+
+Every deploy formula must verify that the deployed artifact has a **return path**
+before marking the deploy complete. An addressable without measurement is Fold 2
+without Fold 3 — shipped but not learned from.
+
+## How it works
+
+Deploy formulas add a final `verify-observable` step that checks:
+
+1. **Measurement infrastructure exists** — the mechanism that captures engagement
+   data is present and active (log file, analytics endpoint, event stream).
+2. **Collection script is in place** — a process exists to transform raw signals
+   into structured evidence in `evidence/<domain>/YYYY-MM-DD.json`.
+3. **Evidence has been collected** — at least one report exists (or a note that
+   the first collection is pending).
+
+The step is advisory, not blocking — a deploy succeeds even if measurement
+isn't yet active. But the output makes the gap visible to the planner, which
+will file issues to close it.
+
+## Artifact types and their return paths
+
+| Artifact type | Addressable | Measurement source | Evidence path |
+|---------------|-------------|-------------------|---------------|
+| Static site | URL (disinto.ai) | Caddy access logs | `evidence/engagement/` |
+| npm package | Registry name | Download counts API | `evidence/package/` |
+| Smart contract | Contract address | On-chain events (Ponder) | `evidence/protocol/` |
+| Docker image | Registry tag | Pull counts API | `evidence/container/` |
+
+## Adding observable verification to a deploy formula
+
+Add a `[[steps]]` block after the deploy verification step:
+
+```toml
+[[steps]]
+id          = "verify-observable"
+title       = "Verify engagement measurement is active"
+description = """
+Check that measurement infrastructure is active for this artifact.
+
+1. Verify the data source exists and is recent
+2. Verify the collection script is present
+3. Report latest evidence if available
+
+Observable status summary:
+  addressable=<what was deployed>
+  measurement=<data source>
+  evidence=<path to evidence directory>
+  consumer=planner (gap analysis)
+"""
+needs       = ["verify"]
+```
+
+## Evidence format
+
+Each evidence file is dated JSON committed to `evidence/<domain>/YYYY-MM-DD.json`.
+The planner reads these during gap analysis. The predictor challenges staleness.
+
+Minimum fields for engagement evidence:
+
+```json
+{
+  "date": "2026-03-26",
+  "period_hours": 24,
+  "unique_visitors": 42,
+  "page_views": 156,
+  "top_pages": [{"path": "/", "views": 89}],
+  "top_referrers": [{"source": "news.ycombinator.com", "visits": 12}]
+}
+```
+
+## The loop
+
+```
+deploy formula
+  → verify-observable step confirms measurement is active
+    → collect-engagement.sh (cron) parses logs → evidence/engagement/
+      → planner reads evidence → identifies gaps → creates issues
+        → dev-agent implements → deploy formula runs again
+```
+
+This is the bridge from Fold 2 (ship) to Fold 3 (learn).
diff --git a/evidence/engagement/.gitkeep b/evidence/engagement/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/formulas/run-publish-site.toml b/formulas/run-publish-site.toml
index 8c57a85..cd3624f 100644
--- a/formulas/run-publish-site.toml
+++ b/formulas/run-publish-site.toml
@@ -178,3 +178,51 @@ Clean up temp files:
   rm -f /tmp/publish-site-deploy-sha /tmp/publish-site-deploy-target
 """
 needs       = ["prune-old-deploys"]
+
+[[steps]]
+id          = "verify-observable"
+title       = "Verify engagement measurement is active"
+description = """
+Every deploy must confirm that the addressable has a return path (observable).
+This is the bridge from Ship (Fold 2) to Learn (Fold 3).
+
+Check 1 — Caddy access log exists and is being written:
+  CADDY_LOG="${CADDY_ACCESS_LOG:-/var/log/caddy/access.log}"
+  if [ ! -f "$CADDY_LOG" ]; then
+    echo "WARNING: Caddy access log not found at $CADDY_LOG"
+    echo "Engagement measurement is NOT active — set CADDY_ACCESS_LOG if the path differs."
+  else
+    AGE_MIN=$(( ($(date +%s) - $(stat -c %Y "$CADDY_LOG" 2>/dev/null || echo 0)) / 60 ))
+    if [ "$AGE_MIN" -gt 60 ]; then
+      echo "WARNING: Caddy access log is ${AGE_MIN} minutes old — may not be active"
+    else
+      echo "OK: Caddy access log is active (last written ${AGE_MIN}m ago)"
+    fi
+  fi
+
+Check 2 — collect-engagement.sh is present in the repo:
+  FACTORY_ROOT="${FACTORY_ROOT:-/home/debian/dark-factory}"
+  if [ -x "$FACTORY_ROOT/site/collect-engagement.sh" ]; then
+    echo "OK: collect-engagement.sh is present and executable"
+  else
+    echo "WARNING: collect-engagement.sh not found or not executable"
+  fi
+
+Check 3 — engagement evidence has been collected at least once:
+  EVIDENCE_DIR="$FACTORY_ROOT/evidence/engagement"
+  LATEST=$(ls -1t "$EVIDENCE_DIR"/*.json 2>/dev/null | head -1 || true)
+  if [ -n "$LATEST" ]; then
+    echo "OK: Latest engagement report: $LATEST"
+    jq -r '"  visitors=\(.unique_visitors) pages=\(.page_views) referrals=\(.referred_visitors)"' "$LATEST" 2>/dev/null || true
+  else
+    echo "NOTE: No engagement reports yet — run: bash site/collect-engagement.sh"
+    echo "The first report will appear after the cron job runs (daily at 23:55 UTC)."
+  fi
+
+Summary:
+  echo ""
+  echo "Observable status: addressable=disinto.ai measurement=caddy-access-logs"
+  echo "Evidence path: evidence/engagement/YYYY-MM-DD.json"
+  echo "Consumer: planner reads evidence/engagement/ during gap analysis"
+"""
+needs       = ["verify"]
diff --git a/site/collect-engagement.sh b/site/collect-engagement.sh
new file mode 100644
index 0000000..c5975c6
--- /dev/null
+++ b/site/collect-engagement.sh
@@ -0,0 +1,192 @@
+#!/usr/bin/env bash
+# =============================================================================
+# collect-engagement.sh — Parse Caddy access logs into engagement evidence
+#
+# Reads Caddy's structured JSON access log, extracts visitor engagement data
+# for the last 24 hours, and writes a dated JSON report to evidence/engagement/.
+#
+# The planner consumes these reports to close the build→ship→learn loop:
+# an addressable (disinto.ai) becomes observable when engagement data flows back.
+#
+# Usage:
+#   bash site/collect-engagement.sh
+#
+# Cron: 55 23 * * * cd /home/debian/dark-factory && bash site/collect-engagement.sh
+# =============================================================================
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+FACTORY_ROOT="$(dirname "$SCRIPT_DIR")"
+
+# shellcheck source=../lib/env.sh
+source "$FACTORY_ROOT/lib/env.sh"
+
+LOGFILE="${FACTORY_ROOT}/site/collect-engagement.log"
+log() {
+  printf '[%s] collect-engagement: %s\n' \
+    "$(date -u '+%Y-%m-%d %H:%M:%S UTC')" "$*" >> "$LOGFILE"
+}
+
+# ── Configuration ────────────────────────────────────────────────────────────
+
+# Caddy structured access log (JSON lines)
+CADDY_LOG="${CADDY_ACCESS_LOG:-/var/log/caddy/access.log}"
+
+# Evidence output directory (committed to git)
+EVIDENCE_DIR="${FACTORY_ROOT}/evidence/engagement"
+
+# Report date — defaults to today
+REPORT_DATE=$(date -u +%Y-%m-%d)
+
+# Cutoff: only process entries from the last 24 hours
+CUTOFF_TS=$(date -u -d '24 hours ago' +%s 2>/dev/null \
+  || date -u -v-24H +%s 2>/dev/null \
+  || echo 0)
+
+# ── Preflight checks ────────────────────────────────────────────────────────
+
+if [ ! -f "$CADDY_LOG" ]; then
+  log "ERROR: Caddy access log not found at ${CADDY_LOG}"
+  echo "ERROR: Caddy access log not found at ${CADDY_LOG}" >&2
+  echo "Set CADDY_ACCESS_LOG to the correct path." >&2
+  exit 1
+fi
+
+if ! command -v jq &>/dev/null; then
+  log "ERROR: jq is required but not installed"
+  exit 1
+fi
+
+mkdir -p "$EVIDENCE_DIR"
+
+# ── Parse access log ────────────────────────────────────────────────────────
+
+log "Parsing ${CADDY_LOG} for entries since $(date -u -d "@${CUTOFF_TS}" +%Y-%m-%dT%H:%M:%SZ 2>/dev/null || echo "${CUTOFF_TS}")"
+
+# Extract relevant fields from Caddy JSON log lines.
+# Caddy v2 structured log format:
+#   ts (float epoch), request.uri, request.remote_ip, request.headers.Referer,
+#   request.headers.User-Agent, status, size, duration
+#
+# Filter to last 24h, exclude assets/bots, produce a clean JSONL stream.
+PARSED=$(jq -c --argjson cutoff "$CUTOFF_TS" '
+  select(.ts >= $cutoff)
+  | select(.request.uri != null)
+  | {
+      ts: .ts,
+      ip: (.request.remote_ip // .request.remote_addr // "unknown"
+           | split(":")[0]),
+      uri: .request.uri,
+      status: .status,
+      size: .size,
+      duration: .duration,
+      referer: (.request.headers.Referer[0] // .request.headers.referer[0]
+                // "direct"),
+      ua: (.request.headers["User-Agent"][0]
+           // .request.headers["user-agent"][0] // "unknown")
+    }
+' "$CADDY_LOG" 2>/dev/null || echo "")
+
+if [ -z "$PARSED" ]; then
+  log "No entries found in the last 24 hours"
+  jq -nc \
+    --arg date "$REPORT_DATE" \
+    --arg source "$CADDY_LOG" \
+    '{
+      date: $date,
+      source: $source,
+      period_hours: 24,
+      total_requests: 0,
+      unique_visitors: 0,
+      page_views: 0,
+      top_pages: [],
+      top_referrers: [],
+      note: "no entries in period"
+    }' > "${EVIDENCE_DIR}/${REPORT_DATE}.json"
+  log "Empty report written to ${EVIDENCE_DIR}/${REPORT_DATE}.json"
+  exit 0
+fi
+
+# ── Compute engagement metrics ──────────────────────────────────────────────
+
+# Filter out static assets and known bots for page-view metrics
+PAGES=$(printf '%s\n' "$PARSED" | jq -c '
+  select(
+    (.uri | test("\\.(css|js|png|jpg|jpeg|webp|ico|svg|woff2?|ttf|map)$") | not)
+    and (.ua | test("bot|crawler|spider|slurp|Googlebot|Bingbot|YandexBot"; "i") | not)
+    and (.status >= 200 and .status < 400)
+  )
+')
+
+TOTAL_REQUESTS=$(printf '%s\n' "$PARSED" | wc -l | tr -d ' ')
+PAGE_VIEWS=$(printf '%s\n' "$PAGES" | grep -c . || echo 0)
+UNIQUE_VISITORS=$(printf '%s\n' "$PAGES" | jq -r '.ip' | sort -u | wc -l | tr -d ' ')
+
+# Top pages by hit count
+TOP_PAGES=$(printf '%s\n' "$PAGES" | jq -r '.uri' \
+  | sort | uniq -c | sort -rn | head -10 \
+  | awk '{printf "{\"path\":\"%s\",\"views\":%d}\n", $2, $1}' \
+  | jq -sc '.')
+
+# Top referrers (exclude direct/self)
+TOP_REFERRERS=$(printf '%s\n' "$PAGES" | jq -r '.referer' \
+  | grep -v '^direct$' \
+  | grep -v '^-$' \
+  | grep -v 'disinto\.ai' \
+  | sort | uniq -c | sort -rn | head -10 \
+  | awk '{printf "{\"source\":\"%s\",\"visits\":%d}\n", $2, $1}' \
+  | jq -sc '.' 2>/dev/null || echo '[]')
+
+# Unique visitors who came from external referrers
+REFERRED_VISITORS=$(printf '%s\n' "$PAGES" | jq -r 'select(.referer != "direct" and .referer != "-" and (.referer | test("disinto\\.ai") | not)) | .ip' \
+  | sort -u | wc -l | tr -d ' ')
+
+# Response time stats (p50, p95, p99 in ms)
+RESPONSE_TIMES=$(printf '%s\n' "$PAGES" | jq -r '.duration // 0' | sort -n)
+RT_COUNT=$(printf '%s\n' "$RESPONSE_TIMES" | wc -l | tr -d ' ')
+if [ "$RT_COUNT" -gt 0 ]; then
+  P50_IDX=$(( (RT_COUNT * 50 + 99) / 100 ))
+  P95_IDX=$(( (RT_COUNT * 95 + 99) / 100 ))
+  P99_IDX=$(( (RT_COUNT * 99 + 99) / 100 ))
+  P50=$(printf '%s\n' "$RESPONSE_TIMES" | sed -n "${P50_IDX}p")
+  P95=$(printf '%s\n' "$RESPONSE_TIMES" | sed -n "${P95_IDX}p")
+  P99=$(printf '%s\n' "$RESPONSE_TIMES" | sed -n "${P99_IDX}p")
+else
+  P50=0; P95=0; P99=0
+fi
+
+# ── Write evidence ──────────────────────────────────────────────────────────
+
+OUTPUT="${EVIDENCE_DIR}/${REPORT_DATE}.json"
+
+jq -nc \
+  --arg date "$REPORT_DATE" \
+  --arg source "$CADDY_LOG" \
+  --argjson total_requests "$TOTAL_REQUESTS" \
+  --argjson page_views "$PAGE_VIEWS" \
+  --argjson unique_visitors "$UNIQUE_VISITORS" \
+  --argjson referred_visitors "$REFERRED_VISITORS" \
+  --argjson top_pages "$TOP_PAGES" \
+  --argjson top_referrers "$TOP_REFERRERS" \
+  --argjson p50 "${P50:-0}" \
+  --argjson p95 "${P95:-0}" \
+  --argjson p99 "${P99:-0}" \
+  '{
+    date: $date,
+    source: $source,
+    period_hours: 24,
+    total_requests: $total_requests,
+    page_views: $page_views,
+    unique_visitors: $unique_visitors,
+    referred_visitors: $referred_visitors,
+    top_pages: $top_pages,
+    top_referrers: $top_referrers,
+    response_time: {
+      p50_seconds: $p50,
+      p95_seconds: $p95,
+      p99_seconds: $p99
+    }
+  }' > "$OUTPUT"
+
+log "Engagement report written to ${OUTPUT}: ${UNIQUE_VISITORS} visitors, ${PAGE_VIEWS} page views"
+echo "Engagement report: ${UNIQUE_VISITORS} unique visitors, ${PAGE_VIEWS} page views → ${OUTPUT}"