diff --git a/docs/contract-ops-runbook.md b/docs/contract-ops-runbook.md
index 6bd52d4..e83fa7d 100644
--- a/docs/contract-ops-runbook.md
+++ b/docs/contract-ops-runbook.md
@@ -250,3 +250,28 @@ Everything in Section 4–5 is identical on mainnet except:
 - The cold recovery key actually lives in a safe; the daily signers are you + co-founder.
 - After rotation, **destroy the initial deploy key** (`shred -u`); it has no power post-rotation but leave nothing lying around.
 - The enumerable token index is complete **from genesis** — register USDC at deploy time and state enumeration is authoritative forever (no import-by-address needed, unlike the in-place-upgraded testnet contract).
+
+
+---
+
+## 5. Fee account trustline verification & event alerting (DoS.15)
+
+**Context:**
+As identified in threat model finding **DoS.15**, `set_fee_account` performs no pre-flight verification, and `deposit_with_fee_at` / `release_with_fee_at` transfer protocol fees directly to `fee_account`. If the fee account lacks an active, authorized trustline for a supported token, user transactions (`create_event`, `add_funds`, and crowdfunding `claim_milestone`) will revert.
+
+### Pre-flight Verification Runbook
+Before executing `register_supported_token` or `set_fee_account`:
+
+1. Run the trustline verification script against the fee account:
+   ```bash
+   ./scripts/admin/verify-fee-trustline.sh <FEE_ACCOUNT_G_ADDRESS> <network> <ASSET_CODE:ISSUER ...>
+   ```
+2. Verify all checks pass:
+   - Account exists on target network.
+   - Trustline exists in `.balances[]` for each registered/target token.
+   - `is_authorized` is `true`.
+
+### Event Alerting & Monitoring
+- Configure monitoring alerts on the indexer / event listener for:
+  - `FeeAccountUpdated`: Triggers automated check to verify the new fee account holds trustlines for all active supported tokens.
+  - `TokenRegistered`: Triggers verification that the current fee account holds a trustline for the newly registered token.
diff --git a/docs/multisig-preflight.md b/docs/multisig-preflight.md
index 3372b7b..aec0fbf 100644
--- a/docs/multisig-preflight.md
+++ b/docs/multisig-preflight.md
@@ -89,6 +89,20 @@ Before touching mainnet:
 
 The same procedure is required quarterly per policy §5.3; this just exercises it under realistic conditions before mainnet.
 
+
+---
+
+## 4.B Fee account & token trustline pre-flight (DoS.15 mitigation)
+
+Before calling `register_supported_token` or rotating the fee account with `set_fee_account`:
+
+- [ ] Confirm the candidate `fee_account` G-address is funded and active on the target network.
+- [ ] For every token already supported or proposed for registration, verify that `fee_account` holds an active, authorized trustline:
+  ```bash
+  ./scripts/admin/verify-fee-trustline.sh <FEE_ACCOUNT_G_ADDRESS> <testnet|mainnet> <ASSET_CODE:ISSUER>
+  ```
+- [ ] Verify that no un-trustlined or unauthorized token is registered, preventing contract fee collection reverts in `deposit_with_fee_at` / `release_with_fee_at`.
+
 ## 5. Rotate admin authority
 
 Only after every box above is checked:
diff --git a/scripts/admin/verify-fee-trustline.sh b/scripts/admin/verify-fee-trustline.sh
new file mode 100755
index 0000000..8325281
--- /dev/null
+++ b/scripts/admin/verify-fee-trustline.sh
@@ -0,0 +1,112 @@
+#!/bin/bash
+#
+# verify-fee-trustline.sh: verify that the fee account holds active, authorized
+# trustlines for all supported/candidate tokens before `register_supported_token`
+# or `set_fee_account` is executed.
+#
+# Threat Model Reference: DoS.15 (Process control for unverified fee trustlines).
+# Without a valid trustline, fee collection in `deposit_with_fee_at` /
+# `release_with_fee_at` will revert, causing `create_event`, `add_funds`, and
+# crowdfunding `claim_milestone` to fail.
+#
+# Usage:
+#   ./scripts/admin/verify-fee-trustline.sh <FEE_ACCOUNT_G_ADDRESS> [testnet|mainnet] [ASSET_CODE:ISSUER ...]
+#
+# Example:
+#   ./scripts/admin/verify-fee-trustline.sh GA... testnet USDC:GB...
+
+set -euo pipefail
+
+if ! command -v curl &>/dev/null; then
+    echo "Error: curl is required." >&2
+    exit 1
+fi
+if ! command -v jq &>/dev/null; then
+    echo "Error: jq is required (e.g., brew install jq or apt install jq)." >&2
+    exit 1
+fi
+
+FEE_ACCOUNT=${1:-""}
+NETWORK=${2:-"testnet"}
+shift 2 || true
+ASSETS=("$@")
+
+if [[ -z "$FEE_ACCOUNT" ]]; then
+    echo "Usage: $0 <FEE_ACCOUNT_G_ADDRESS> [testnet|mainnet] [ASSET_CODE:ISSUER ...]" >&2
+    exit 1
+fi
+
+case "$NETWORK" in
+    testnet) HORIZON="https://horizon-testnet.stellar.org" ;;
+    mainnet) HORIZON="https://horizon.stellar.org" ;;
+    *)       echo "Unknown network '$NETWORK'." >&2; exit 1 ;;
+esac
+
+GREEN='\033[0;32m'; RED='\033[0;31m'; YELLOW='\033[1;33m'; NC='\033[0m'
+
+echo -e "${YELLOW}Verifying fee account ${FEE_ACCOUNT} on ${NETWORK}...${NC}"
+
+ACCOUNT_JSON=$(curl -sf "$HORIZON/accounts/$FEE_ACCOUNT" || true)
+if [[ -z "$ACCOUNT_JSON" ]]; then
+    echo -e "${RED}Error: Fee account ${FEE_ACCOUNT} not found on ${NETWORK}.${NC}" >&2
+    exit 1
+fi
+
+PASS=0
+FAIL=0
+
+echo -e "  ${GREEN}✓${NC} Account exists on ${NETWORK}"
+PASS=$((PASS + 1))
+
+# Inspect active balances on the fee account
+BALANCES=$(echo "$ACCOUNT_JSON" | jq -r '.balances')
+
+if [[ ${#ASSETS[@]} -eq 0 ]]; then
+    echo -e "\n${YELLOW}Discovered trustlines/balances on fee account:${NC}"
+    echo "$BALANCES" | jq -r '.[] | "  - " + (if .asset_type == "native" then "XLM (native)" else (.asset_code + ":" + .asset_issuer) end) + " (balance: " + .balance + ", authorized: " + (.is_authorized // true | tostring) + ")"'
+else
+    echo -e "\n${YELLOW}Asserting required trustlines:${NC}"
+    for ASSET in "${ASSETS[@]}"; do
+        if [[ "$ASSET" == "XLM" || "$ASSET" == "native" ]]; then
+            HAS_NATIVE=$(echo "$BALANCES" | jq -r '[.[] | select(.asset_type == "native")] | length')
+            if [[ "$HAS_NATIVE" -gt 0 ]]; then
+                echo -e "  ${GREEN}✓${NC} XLM (native balance available)"
+                PASS=$((PASS + 1))
+            else
+                echo -e "  ${RED}✗${NC} Missing native XLM balance on fee account"
+                FAIL=$((FAIL + 1))
+            fi
+            continue
+        fi
+
+        CODE="${ASSET%%:*}"
+        ISSUER="${ASSET##*:}"
+
+        # Match either exact code+issuer or asset code
+        MATCH=$(echo "$BALANCES" | jq -r --arg code "$CODE" --arg issuer "$ISSUER" \
+            '[.[] | select(.asset_code == $code and .asset_issuer == $issuer)] | .[0]')
+
+        if [[ -n "$MATCH" && "$MATCH" != "null" ]]; then
+            IS_AUTH=$(echo "$MATCH" | jq -r '.is_authorized // false')
+            if [[ "$IS_AUTH" == "true" ]]; then
+                echo -e "  ${GREEN}✓${NC} Trustline active & authorized: ${ASSET}"
+                PASS=$((PASS + 1))
+            else
+                echo -e "  ${RED}✗${NC} Trustline exists but is NOT authorized: ${ASSET}"
+                FAIL=$((FAIL + 1))
+            fi
+        else
+            echo -e "  ${RED}✗${NC} Missing trustline for: ${ASSET}"
+            FAIL=$((FAIL + 1))
+        fi
+    done
+fi
+
+echo
+if [[ $FAIL -gt 0 ]]; then
+    echo -e "${RED}FAIL: $FAIL check(s) failed; $PASS passed.${NC}" >&2
+    echo "Do NOT register this token or rotate fee account until trustlines are established and authorized." >&2
+    exit 1
+fi
+
+echo -e "${GREEN}PASS: Fee account trustline verification successful.${NC}"
diff --git a/scripts/admin/verify-multisig.sh b/scripts/admin/verify-multisig.sh
index 4dbcab5..46fb8a3 100755
--- a/scripts/admin/verify-multisig.sh
+++ b/scripts/admin/verify-multisig.sh
@@ -105,4 +105,5 @@ echo
 echo "Next steps:"
 echo "  1. Compare the printed signer addresses against the founder's roster."
 echo "  2. Confirm each signer can sign a test transaction (drill)."
-echo "  3. Only then run set_admin per docs/mainnet-deploy-runbook.md §2.7."
+echo "  3. Verify fee account trustlines via ./scripts/admin/verify-fee-trustline.sh (DoS.15)."
+echo "  4. Only then run set_admin per docs/mainnet-deploy-runbook.md §2.7."