diff --git a/Makefile b/Makefile
index fb1c13d93..751825572 100644
--- a/Makefile
+++ b/Makefile
@@ -100,6 +100,7 @@ go-tidy:
 script-test:
 	bash internal/scaffold/fullsend-repo/scripts/post-triage-test.sh
 	bash internal/scaffold/fullsend-repo/scripts/validate-output-schema-test.sh
+	bash internal/scaffold/fullsend-repo/scripts/pre-code-test.sh
 
 test: lint go-vet go-test script-test
 
diff --git a/internal/scaffold/fullsend-repo/scripts/pre-code-test.sh b/internal/scaffold/fullsend-repo/scripts/pre-code-test.sh
new file mode 100644
index 000000000..ff146d4fe
--- /dev/null
+++ b/internal/scaffold/fullsend-repo/scripts/pre-code-test.sh
@@ -0,0 +1,241 @@
+#!/usr/bin/env bash
+# pre-code-test.sh — Test pre-code.sh with mock gh to verify existing-PR check.
+#
+# Uses a mock gh command to capture calls without hitting GitHub.
+# Run from the repo root: bash internal/scaffold/fullsend-repo/scripts/pre-code-test.sh
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+PRE_SCRIPT="${SCRIPT_DIR}/pre-code.sh"
+FAILURES=0
+
+# Create a temp directory for mock state.
+TMPDIR="$(mktemp -d)"
+trap 'rm -rf "${TMPDIR}"' EXIT
+
+# --- Helpers ---
+
+# build_mock creates a mock gh binary that returns preconfigured responses.
+# Arguments:
+#   $1 — output to return for "gh pr list" calls (tab-separated lines
+#         matching what gh --jq would produce, or empty for no PRs)
+build_mock() {
+  local pr_list_output="$1"
+  local mock_bin="${TMPDIR}/bin"
+  local gh_log="${TMPDIR}/gh-calls.log"
+
+  rm -rf "${mock_bin}"
+  mkdir -p "${mock_bin}"
+  > "${gh_log}"
+
+  # Write the pr list output to a file so the mock can read it.
+  printf '%s' "${pr_list_output}" > "${TMPDIR}/pr-list-output.txt"
+
+  cat > "${mock_bin}/gh" <<'MOCKEOF'
+#!/usr/bin/env bash
+CALL_LOG="LOGFILE_PLACEHOLDER"
+PR_OUTPUT="OUTPUT_PLACEHOLDER"
+
+echo "gh $*" >> "${CALL_LOG}"
+
+# Route by subcommand
+if [[ "$1" == "pr" && "$2" == "list" ]]; then
+  cat "${PR_OUTPUT}"
+elif [[ "$1" == "label" ]]; then
+  exit 0
+elif [[ "$1" == "api" ]]; then
+  exit 0
+elif [[ "$1" == "issue" && "$2" == "comment" ]]; then
+  # Consume stdin (body-file reads from stdin)
+  cat > /dev/null
+  exit 0
+fi
+MOCKEOF
+
+  # Patch placeholders with actual paths (avoid sed on source files,
+  # but this is a generated mock — not repo source code).
+  local escaped_log="${gh_log//\//\\/}"
+  local escaped_out="${TMPDIR//\//\\/}\/pr-list-output.txt"
+  perl -pi -e "s/LOGFILE_PLACEHOLDER/${escaped_log}/g" "${mock_bin}/gh"
+  perl -pi -e "s/OUTPUT_PLACEHOLDER/${escaped_out}/g" "${mock_bin}/gh"
+
+  chmod +x "${mock_bin}/gh"
+
+  echo "${mock_bin}"
+}
+
+run_test() {
+  local test_name="$1"
+  local pr_list_output="$2"
+  local expected_pattern="$3"
+  local expect_exit="$4"         # 0 = success, 1 = failure
+  local extra_env="${5:-}"       # additional env vars (KEY=VAL KEY2=VAL2)
+
+  local mock_bin
+  mock_bin="$(build_mock "${pr_list_output}")"
+  local gh_log="${TMPDIR}/gh-calls.log"
+
+  # Set base env vars for the script.
+  local env_cmd=(
+    env
+    PATH="${mock_bin}:${PATH}"
+    ISSUE_NUMBER="42"
+    REPO_FULL_NAME="test-org/test-repo"
+    GITHUB_ISSUE_URL="https://github.com/test-org/test-repo/issues/42"
+    GH_TOKEN="fake-token"
+  )
+
+  # Add extra env vars if provided.
+  if [[ -n "${extra_env}" ]]; then
+    for kv in ${extra_env}; do
+      env_cmd+=("${kv}")
+    done
+  fi
+
+  local exit_code=0
+  "${env_cmd[@]}" bash "${PRE_SCRIPT}" > "${TMPDIR}/stdout.log" 2>&1 || exit_code=$?
+
+  # Check exit code.
+  if [[ ${exit_code} -ne ${expect_exit} ]]; then
+    echo "FAIL: ${test_name} — expected exit ${expect_exit}, got ${exit_code}"
+    cat "${TMPDIR}/stdout.log"
+    FAILURES=$((FAILURES + 1))
+    return
+  fi
+
+  # Check expected pattern in gh calls (if provided).
+  if [[ -n "${expected_pattern}" ]]; then
+    if ! grep -qF "${expected_pattern}" "${gh_log}" 2>/dev/null; then
+      echo "FAIL: ${test_name} — expected gh call pattern '${expected_pattern}' not found"
+      echo "Actual calls:"
+      cat "${gh_log}" 2>/dev/null || echo "(no calls)"
+      FAILURES=$((FAILURES + 1))
+      return
+    fi
+  fi
+
+  echo "PASS: ${test_name}"
+}
+
+# Check stdout contains a specific string.
+run_test_stdout() {
+  local test_name="$1"
+  local pr_list_output="$2"
+  local expected_stdout="$3"
+  local expect_exit="$4"
+  local extra_env="${5:-}"
+
+  local mock_bin
+  mock_bin="$(build_mock "${pr_list_output}")"
+
+  local env_cmd=(
+    env
+    PATH="${mock_bin}:${PATH}"
+    ISSUE_NUMBER="42"
+    REPO_FULL_NAME="test-org/test-repo"
+    GITHUB_ISSUE_URL="https://github.com/test-org/test-repo/issues/42"
+    GH_TOKEN="fake-token"
+  )
+
+  if [[ -n "${extra_env}" ]]; then
+    for kv in ${extra_env}; do
+      env_cmd+=("${kv}")
+    done
+  fi
+
+  local exit_code=0
+  "${env_cmd[@]}" bash "${PRE_SCRIPT}" > "${TMPDIR}/stdout.log" 2>&1 || exit_code=$?
+
+  if [[ ${exit_code} -ne ${expect_exit} ]]; then
+    echo "FAIL: ${test_name} — expected exit ${expect_exit}, got ${exit_code}"
+    cat "${TMPDIR}/stdout.log"
+    FAILURES=$((FAILURES + 1))
+    return
+  fi
+
+  if ! grep -qF "${expected_stdout}" "${TMPDIR}/stdout.log" 2>/dev/null; then
+    echo "FAIL: ${test_name} — expected stdout '${expected_stdout}' not found"
+    echo "Actual stdout:"
+    cat "${TMPDIR}/stdout.log"
+    FAILURES=$((FAILURES + 1))
+    return
+  fi
+
+  echo "PASS: ${test_name}"
+}
+
+# --- Test cases ---
+
+# Tab character for readability.
+TAB=$'\t'
+
+# No existing PRs → agent proceeds (exit 0, no label/comment).
+run_test_stdout "no-existing-prs-proceeds" \
+  "" \
+  "No existing human PRs found" \
+  0
+
+# Human PR exists → should apply label and comment, then exit 0.
+run_test "human-pr-applies-label" \
+  "99${TAB}human-dev${TAB}https://github.com/test-org/test-repo/pull/99" \
+  "gh api repos/test-org/test-repo/issues/42/labels -f labels[]=pr-open --silent" \
+  0
+
+run_test "human-pr-posts-comment" \
+  "99${TAB}human-dev${TAB}https://github.com/test-org/test-repo/pull/99" \
+  "gh issue comment 42 --repo test-org/test-repo --body-file -" \
+  0
+
+run_test_stdout "human-pr-skips-agent" \
+  "99${TAB}human-dev${TAB}https://github.com/test-org/test-repo/pull/99" \
+  "Skipping code agent" \
+  0
+
+# Bot PR only → gh --jq filters it out, so pr list returns empty → proceeds.
+run_test_stdout "bot-pr-does-not-block" \
+  "" \
+  "No existing human PRs found" \
+  0
+
+# CODE_FORCE=true → should skip check even with human PR.
+run_test_stdout "force-override-skips-check" \
+  "99${TAB}human-dev${TAB}https://github.com/test-org/test-repo/pull/99" \
+  "CODE_FORCE=true" \
+  0 \
+  "CODE_FORCE=true"
+
+# No GH_TOKEN → skips check entirely, exits 0.
+run_test_stdout "no-gh-token-skips-check" \
+  "" \
+  "GH_TOKEN not set" \
+  0 \
+  "GH_TOKEN="
+
+# Multiple human PRs → should block and apply label.
+run_test "multiple-human-prs-block" \
+  "50${TAB}dev-a${TAB}https://github.com/test-org/test-repo/pull/50
+51${TAB}dev-b${TAB}https://github.com/test-org/test-repo/pull/51" \
+  "gh api repos/test-org/test-repo/issues/42/labels -f labels[]=pr-open --silent" \
+  0
+
+run_test_stdout "multiple-human-prs-notice" \
+  "50${TAB}dev-a${TAB}https://github.com/test-org/test-repo/pull/50
+51${TAB}dev-b${TAB}https://github.com/test-org/test-repo/pull/51" \
+  "Found existing human PR #50 by @dev-a" \
+  0
+
+# PR label gets created.
+run_test "pr-label-created" \
+  "99${TAB}human-dev${TAB}https://github.com/test-org/test-repo/pull/99" \
+  "gh label create pr-open --repo test-org/test-repo" \
+  0
+
+# --- Summary ---
+
+echo ""
+if [[ ${FAILURES} -gt 0 ]]; then
+  echo "${FAILURES} test(s) failed"
+  exit 1
+fi
+echo "All tests passed"
diff --git a/internal/scaffold/fullsend-repo/scripts/pre-code.sh b/internal/scaffold/fullsend-repo/scripts/pre-code.sh
index eae9c65bd..4ff5bc8da 100755
--- a/internal/scaffold/fullsend-repo/scripts/pre-code.sh
+++ b/internal/scaffold/fullsend-repo/scripts/pre-code.sh
@@ -50,3 +50,68 @@ echo "Input validation passed:"
 echo "  ISSUE_NUMBER=${ISSUE_NUMBER}"
 echo "  REPO_FULL_NAME=${REPO_FULL_NAME}"
 echo "  GITHUB_ISSUE_URL=${GITHUB_ISSUE_URL}"
+
+# ---------------------------------------------------------------------------
+# Check for existing human PRs linked to this issue
+# ---------------------------------------------------------------------------
+# Skip if GH_TOKEN is not available (best-effort check).
+if [[ -z "${GH_TOKEN:-}" ]]; then
+  echo "GH_TOKEN not set — skipping existing-PR check"
+  exit 0
+fi
+
+# Allow override via CODE_FORCE (set when /code --force is used).
+if [[ "${CODE_FORCE:-}" == "true" ]]; then
+  echo "CODE_FORCE=true — skipping existing-PR check"
+  exit 0
+fi
+
+BOT_LOGIN="${FULLSEND_BOT_LOGIN:-fullsend-ai[bot]}"
+
+echo "Checking for existing open PRs linked to issue #${ISSUE_NUMBER}..."
+
+# Search for open PRs in the repo that mention the issue number.
+# This catches PRs with "Closes #N", "Fixes #N", or "#N" in the body/title.
+# Use gh's built-in --jq to filter out bot-authored PRs in one call.
+HUMAN_PR_LINES="$(gh pr list --repo "${REPO_FULL_NAME}" --state open \
+  --search "${ISSUE_NUMBER} in:body,title" \
+  --json number,url,author \
+  --jq "[.[] | select(.author.login != \"${BOT_LOGIN}\")] | .[] | \"\(.number)\t\(.author.login)\t\(.url)\"" \
+  2>/dev/null || true)"
+
+if [[ -n "${HUMAN_PR_LINES}" ]]; then
+  # Parse the first PR for the notice.
+  FIRST_PR_NUM="$(echo "${HUMAN_PR_LINES}" | head -1 | cut -f1)"
+  FIRST_PR_AUTHOR="$(echo "${HUMAN_PR_LINES}" | head -1 | cut -f2)"
+
+  echo "::notice::Found existing human PR #${FIRST_PR_NUM} by @${FIRST_PR_AUTHOR}"
+
+  # Apply pr-open label to signal work is already underway.
+  gh label create "pr-open" --repo "${REPO_FULL_NAME}" \
+    --description "An open PR already addresses this issue" --color "D4C5F9" \
+    --force 2>/dev/null || true
+  gh api "repos/${REPO_FULL_NAME}/issues/${ISSUE_NUMBER}/labels" \
+    -f "labels[]=pr-open" --silent 2>/dev/null || true
+
+  # Build a markdown list of existing PRs.
+  PR_LIST_MD=""
+  while IFS=$'\t' read -r pr_num pr_author pr_url; do
+    PR_LIST_MD="${PR_LIST_MD}
+- #${pr_num} by @${pr_author}"
+  done <<< "${HUMAN_PR_LINES}"
+
+  COMMENT_BODY="An open PR already addresses this issue — skipping automated implementation.
+${PR_LIST_MD}
+
+To override, comment \`/code --force\` on this issue.
+
+<sub>Posted by <a href=\"https://github.com/fullsend-ai/fullsend\">fullsend</a> pre-code check</sub>"
+
+  printf '%s' "${COMMENT_BODY}" | gh issue comment "${ISSUE_NUMBER}" \
+    --repo "${REPO_FULL_NAME}" --body-file - 2>/dev/null || true
+
+  echo "Skipping code agent — existing PR(s) found for issue #${ISSUE_NUMBER}"
+  exit 0
+fi
+
+echo "No existing human PRs found — proceeding with code agent"