diff --git a/.woodpecker/agent-smoke.sh b/.woodpecker/agent-smoke.sh
index 40d95b8..a6a1bda 100644
--- a/.woodpecker/agent-smoke.sh
+++ b/.woodpecker/agent-smoke.sh
@@ -91,7 +91,7 @@ echo "=== 2/2  Function resolution ==="
 
 # Functions provided by shared lib files (available to all agent scripts via source)
 LIB_FUNS=$(
-  for f in lib/agent-session.sh lib/env.sh lib/ci-helpers.sh lib/load-project.sh lib/file-action-issue.sh; do
+  for f in lib/agent-session.sh lib/env.sh lib/ci-helpers.sh lib/load-project.sh lib/file-action-issue.sh lib/formula-session.sh; do
     if [ -f "$f" ]; then get_fns "$f"; fi
   done | sort -u
 )
@@ -162,7 +162,7 @@ check_script gardener/gardener-poll.sh
 check_script gardener/gardener-run.sh
 check_script review/review-pr.sh
 check_script review/review-poll.sh
-check_script planner/planner-poll.sh
+check_script planner/planner-run.sh
 check_script supervisor/supervisor-poll.sh
 check_script supervisor/update-prompt.sh
 check_script vault/vault-agent.sh
diff --git a/AGENTS.md b/AGENTS.md
index 646752e..d9d9249 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -291,6 +291,7 @@ sourced as needed.
 | `lib/load-project.sh` | Parses a `projects/*.toml` file into env vars (`PROJECT_NAME`, `CODEBERG_REPO`, `WOODPECKER_REPO_ID`, monitoring toggles, Matrix config, etc.). | env.sh (when `PROJECT_TOML` is set), supervisor-poll (per-project iteration) |
 | `lib/parse-deps.sh` | Extracts dependency issue numbers from an issue body (stdin → stdout, one number per line). Matches `## Dependencies` / `## Depends on` / `## Blocked by` sections and inline `depends on #N` patterns. Not sourced — executed via `bash lib/parse-deps.sh`. | dev-poll, supervisor-poll |
 | `lib/matrix_listener.sh` | Long-poll Matrix sync daemon. Dispatches thread replies to the correct agent via well-known files (`/tmp/{agent}-escalation-reply`). Handles supervisor, gardener, dev, review, vault, and action reply routing. Run as systemd service. | Standalone daemon |
+| `lib/formula-session.sh` | `acquire_cron_lock()`, `check_memory()`, `load_formula()`, `build_context_block()`, `start_formula_session()`, `formula_phase_callback()` — shared helpers for formula-driven cron agents (lock, memory guard, formula loading, tmux session, crash recovery). | planner-run.sh |
 | `lib/file-action-issue.sh` | `file_action_issue()` — dedup check, label lookup, and issue creation for formula-driven cron wrappers. Sets `FILED_ISSUE_NUM` on success. | gardener-run.sh |
 | `lib/agent-session.sh` | Shared tmux + Claude session helpers: `create_agent_session()`, `inject_formula()`, `agent_wait_for_claude_ready()`, `agent_inject_into_session()`, `agent_kill_session()`, `monitor_phase_loop()`, `read_phase()`. `create_agent_session(session, workdir, [phase_file])` optionally installs a PostToolUse hook (matcher `Bash\|Write`) that detects phase file writes in real-time — when Claude writes to the phase file, the hook writes a marker so `monitor_phase_loop` reacts on the next poll instead of waiting for mtime changes. Also installs a StopFailure hook (matcher `rate_limit\|server_error\|authentication_failed\|billing_error`) that writes `PHASE:failed` with an `api_error` reason to the phase file and touches the phase-changed marker, so the orchestrator discovers API errors within one poll cycle instead of waiting for idle timeout. When `MATRIX_THREAD_ID` is exported, also installs a Stop hook (`on-stop-matrix.sh`) that streams each Claude response to the Matrix thread. `monitor_phase_loop` sets `_MONITOR_LOOP_EXIT` to one of: `done`, `idle_timeout`, `idle_prompt` (Claude returned to `❯` for 3 consecutive polls without writing any phase — callback invoked with `PHASE:failed`, session already dead), `crashed`, or a `PHASE:*` string. Agents must handle `idle_prompt` in both their callback and their post-loop exit handler. | dev-agent.sh, gardener-agent.sh, action-agent.sh |
 
diff --git a/gardener/gardener-agent.sh b/gardener/gardener-agent.sh
index 3a3f658..699e8be 100644
--- a/gardener/gardener-agent.sh
+++ b/gardener/gardener-agent.sh
@@ -29,6 +29,8 @@ export PROJECT_TOML="${1:-}"
 source "$FACTORY_ROOT/lib/env.sh"
 # shellcheck source=../lib/agent-session.sh
 source "$FACTORY_ROOT/lib/agent-session.sh"
+# shellcheck source=../lib/formula-session.sh
+source "$FACTORY_ROOT/lib/formula-session.sh"
 
 LOG_FILE="$SCRIPT_DIR/gardener.log"
 SESSION_NAME="gardener-${PROJECT_NAME}"
@@ -275,32 +277,15 @@ matrix_send "gardener" "🌱 Gardener session started for ${CODEBERG_REPO}" 2>/d
 
 # ── Phase monitoring loop ─────────────────────────────────────────────────
 log "Monitoring phase file: ${PHASE_FILE}"
-GARDENER_CRASH_COUNT=0
+_FORMULA_CRASH_COUNT=0
 
 gardener_phase_callback() {
-  local phase="$1"
-  log "phase: ${phase}"
-  case "$phase" in
-    PHASE:crashed)
-      if [ "$GARDENER_CRASH_COUNT" -gt 0 ]; then
-        log "ERROR: session crashed again after recovery — giving up"
-        return 0
-      fi
-      GARDENER_CRASH_COUNT=$((GARDENER_CRASH_COUNT + 1))
-      log "WARNING: tmux session died unexpectedly — attempting recovery"
-      rm -f "$RESULT_FILE"
-      touch "$RESULT_FILE"
-      if create_agent_session "${_MONITOR_SESSION:-$SESSION_NAME}" "$PROJECT_REPO_ROOT" "$PHASE_FILE" 2>/dev/null; then
-        agent_inject_into_session "${_MONITOR_SESSION:-$SESSION_NAME}" "$PROMPT"
-        log "Recovery session started"
-      else
-        log "ERROR: could not restart session after crash"
-      fi
-      ;;
-    PHASE:done|PHASE:failed|PHASE:needs_human|PHASE:merged)
-      agent_kill_session "${_MONITOR_SESSION:-$SESSION_NAME}"
-      ;;
-  esac
+  # Gardener-specific cleanup before shared crash recovery
+  if [ "$1" = "PHASE:crashed" ]; then
+    rm -f "$RESULT_FILE"
+    touch "$RESULT_FILE"
+  fi
+  formula_phase_callback "$1"
 }
 
 monitor_phase_loop "$PHASE_FILE" 7200 "gardener_phase_callback"
diff --git a/lib/formula-session.sh b/lib/formula-session.sh
new file mode 100644
index 0000000..3d73983
--- /dev/null
+++ b/lib/formula-session.sh
@@ -0,0 +1,125 @@
+#!/usr/bin/env bash
+# formula-session.sh — Shared helpers for formula-driven cron agents
+#
+# Provides reusable functions for the common cron-wrapper + tmux-session
+# pattern used by planner-run.sh and gardener-agent.sh.
+#
+# Functions:
+#   acquire_cron_lock   LOCK_FILE          — PID lock with stale cleanup
+#   check_memory        [MIN_MB]           — skip if available RAM too low
+#   load_formula        FORMULA_FILE       — sets FORMULA_CONTENT
+#   build_context_block FILE [FILE ...]    — sets CONTEXT_BLOCK
+#   start_formula_session SESSION WORKDIR PHASE_FILE — create tmux + claude
+#   formula_phase_callback PHASE           — standard crash-recovery callback
+#
+# Requires: lib/agent-session.sh sourced first (for create_agent_session,
+# agent_kill_session, agent_inject_into_session).
+# Globals used by formula_phase_callback: SESSION_NAME, PHASE_FILE,
+# PROJECT_REPO_ROOT, PROMPT (set by the calling script).
+
+# ── Cron guards ──────────────────────────────────────────────────────────
+
+# acquire_cron_lock LOCK_FILE
+# Acquires a PID lock. Exits 0 if another instance is running.
+# Sets an EXIT trap to clean up the lock file.
+acquire_cron_lock() {
+  _CRON_LOCK_FILE="$1"
+  if [ -f "$_CRON_LOCK_FILE" ]; then
+    local lock_pid
+    lock_pid=$(cat "$_CRON_LOCK_FILE" 2>/dev/null || true)
+    if [ -n "$lock_pid" ] && kill -0 "$lock_pid" 2>/dev/null; then
+      log "run: already running (PID $lock_pid)"
+      exit 0
+    fi
+    rm -f "$_CRON_LOCK_FILE"
+  fi
+  echo $$ > "$_CRON_LOCK_FILE"
+  trap 'rm -f "$_CRON_LOCK_FILE"' EXIT
+}
+
+# check_memory [MIN_MB]
+# Exits 0 (skip) if available memory is below MIN_MB (default 2000).
+check_memory() {
+  local min_mb="${1:-2000}"
+  local avail_mb
+  avail_mb=$(free -m | awk '/Mem:/{print $7}')
+  if [ "${avail_mb:-0}" -lt "$min_mb" ]; then
+    log "run: skipping — only ${avail_mb}MB available (need ${min_mb})"
+    exit 0
+  fi
+}
+
+# ── Formula loading ──────────────────────────────────────────────────────
+
+# load_formula FORMULA_FILE
+# Reads formula TOML into FORMULA_CONTENT. Exits 1 if missing.
+load_formula() {
+  local formula_file="$1"
+  if [ ! -f "$formula_file" ]; then
+    log "ERROR: formula not found: $formula_file"
+    exit 1
+  fi
+  # shellcheck disable=SC2034  # consumed by the calling script
+  FORMULA_CONTENT=$(cat "$formula_file")
+}
+
+# build_context_block FILE [FILE ...]
+# Reads each file from $PROJECT_REPO_ROOT and builds CONTEXT_BLOCK.
+build_context_block() {
+  CONTEXT_BLOCK=""
+  local ctx ctx_path
+  for ctx in "$@"; do
+    ctx_path="${PROJECT_REPO_ROOT}/${ctx}"
+    if [ -f "$ctx_path" ]; then
+      CONTEXT_BLOCK="${CONTEXT_BLOCK}
+### ${ctx}
+$(cat "$ctx_path")
+"
+    fi
+  done
+}
+
+# ── Session management ───────────────────────────────────────────────────
+
+# start_formula_session SESSION WORKDIR PHASE_FILE
+# Kills stale session, resets phase file, creates new tmux + claude session.
+# Returns 0 on success, 1 on failure.
+start_formula_session() {
+  local session="$1" workdir="$2" phase_file="$3"
+  agent_kill_session "$session"
+  rm -f "$phase_file"
+  log "Creating tmux session: ${session}"
+  if ! create_agent_session "$session" "$workdir" "$phase_file"; then
+    log "ERROR: failed to create tmux session ${session}"
+    return 1
+  fi
+}
+
+# formula_phase_callback PHASE
+# Standard crash-recovery phase callback for formula sessions.
+# Requires globals: SESSION_NAME, PHASE_FILE, PROJECT_REPO_ROOT, PROMPT.
+# Uses _FORMULA_CRASH_COUNT (auto-initialized) for single-retry limit.
+# shellcheck disable=SC2154  # SESSION_NAME, PHASE_FILE, PROJECT_REPO_ROOT, PROMPT set by caller
+formula_phase_callback() {
+  local phase="$1"
+  log "phase: ${phase}"
+  case "$phase" in
+    PHASE:crashed)
+      if [ "${_FORMULA_CRASH_COUNT:-0}" -gt 0 ]; then
+        log "ERROR: session crashed again after recovery — giving up"
+        return 0
+      fi
+      _FORMULA_CRASH_COUNT=$(( ${_FORMULA_CRASH_COUNT:-0} + 1 ))
+      log "WARNING: tmux session died unexpectedly — attempting recovery"
+      if create_agent_session "${_MONITOR_SESSION:-$SESSION_NAME}" "$PROJECT_REPO_ROOT" "$PHASE_FILE" 2>/dev/null; then
+        agent_inject_into_session "${_MONITOR_SESSION:-$SESSION_NAME}" "$PROMPT"
+        log "Recovery session started"
+      else
+        log "ERROR: could not restart session after crash"
+      fi
+      ;;
+    PHASE:done|PHASE:failed|PHASE:needs_human|PHASE:merged)
+      agent_kill_session "${_MONITOR_SESSION:-$SESSION_NAME}"
+      ;;
+  esac
+}
diff --git a/planner/planner-run.sh b/planner/planner-run.sh
index dbc913f..2ad01cc 100755
--- a/planner/planner-run.sh
+++ b/planner/planner-run.sh
@@ -20,9 +20,10 @@ export PROJECT_TOML="$FACTORY_ROOT/projects/disinto.toml"
 source "$FACTORY_ROOT/lib/env.sh"
 # shellcheck source=../lib/agent-session.sh
 source "$FACTORY_ROOT/lib/agent-session.sh"
+# shellcheck source=../lib/formula-session.sh
+source "$FACTORY_ROOT/lib/formula-session.sh"
 
 LOG_FILE="$SCRIPT_DIR/planner.log"
-LOCK_FILE="/tmp/planner-run.lock"
 SESSION_NAME="planner-${PROJECT_NAME}"
 PHASE_FILE="/tmp/planner-session-${PROJECT_NAME}.phase"
 
@@ -31,46 +32,15 @@ PHASE_POLL_INTERVAL=15
 
 log() { echo "[$(date -u +%Y-%m-%dT%H:%M:%S)Z] $*" >> "$LOG_FILE"; }
 
-# ── Lock ──────────────────────────────────────────────────────────────────
-if [ -f "$LOCK_FILE" ]; then
-  LOCK_PID=$(cat "$LOCK_FILE" 2>/dev/null || true)
-  if [ -n "$LOCK_PID" ] && kill -0 "$LOCK_PID" 2>/dev/null; then
-    log "run: planner running (PID $LOCK_PID)"
-    exit 0
-  fi
-  rm -f "$LOCK_FILE"
-fi
-echo $$ > "$LOCK_FILE"
-trap 'rm -f "$LOCK_FILE"' EXIT
-
-# ── Memory guard ──────────────────────────────────────────────────────────
-AVAIL_MB=$(free -m | awk '/Mem:/{print $7}')
-if [ "${AVAIL_MB:-0}" -lt 2000 ]; then
-  log "run: skipping — only ${AVAIL_MB}MB available (need 2000)"
-  exit 0
-fi
+# ── Guards ────────────────────────────────────────────────────────────────
+acquire_cron_lock "/tmp/planner-run.lock"
+check_memory 2000
 
 log "--- Planner run start ---"
 
-# ── Load formula ─────────────────────────────────────────────────────────
-FORMULA_FILE="$FACTORY_ROOT/formulas/run-planner.toml"
-if [ ! -f "$FORMULA_FILE" ]; then
-  log "ERROR: formula not found: $FORMULA_FILE"
-  exit 1
-fi
-FORMULA_CONTENT=$(cat "$FORMULA_FILE")
-
-# ── Read context files ───────────────────────────────────────────────────
-CONTEXT_BLOCK=""
-for ctx in VISION.md AGENTS.md RESOURCES.md; do
-  ctx_path="${PROJECT_REPO_ROOT}/${ctx}"
-  if [ -f "$ctx_path" ]; then
-    CONTEXT_BLOCK="${CONTEXT_BLOCK}
-### ${ctx}
-$(cat "$ctx_path")
-"
-  fi
-done
+# ── Load formula + context ───────────────────────────────────────────────
+load_formula "$FACTORY_ROOT/formulas/run-planner.toml"
+build_context_block VISION.md AGENTS.md RESOURCES.md
 
 # ── Read planner memory ─────────────────────────────────────────────────
 MEMORY_BLOCK=""
@@ -113,15 +83,9 @@ When all work is done:
 On unrecoverable error:
   printf 'PHASE:failed\nReason: %s\n' 'describe error' > '${PHASE_FILE}'"
 
-# ── Reset phase file + kill stale session ────────────────────────────────
-agent_kill_session "$SESSION_NAME"
-rm -f "$PHASE_FILE"
-
 # ── Create tmux session ─────────────────────────────────────────────────
-log "Creating tmux session: ${SESSION_NAME}"
 export CLAUDE_MODEL="opus"
-if ! create_agent_session "$SESSION_NAME" "$PROJECT_REPO_ROOT" "$PHASE_FILE"; then
-  log "ERROR: failed to create tmux session ${SESSION_NAME}"
+if ! start_formula_session "$SESSION_NAME" "$PROJECT_REPO_ROOT" "$PHASE_FILE"; then
   exit 1
 fi
 
@@ -131,33 +95,9 @@ matrix_send "planner" "Planner session started for ${CODEBERG_REPO}" 2>/dev/null
 
 # ── Phase monitoring loop ────────────────────────────────────────────────
 log "Monitoring phase file: ${PHASE_FILE}"
-PLANNER_CRASH_COUNT=0
+_FORMULA_CRASH_COUNT=0
 
-planner_phase_callback() {
-  local phase="$1"
-  log "phase: ${phase}"
-  case "$phase" in
-    PHASE:crashed)
-      if [ "$PLANNER_CRASH_COUNT" -gt 0 ]; then
-        log "ERROR: session crashed again after recovery — giving up"
-        return 0
-      fi
-      PLANNER_CRASH_COUNT=$((PLANNER_CRASH_COUNT + 1))
-      log "WARNING: tmux session died unexpectedly — attempting recovery"
-      if create_agent_session "${_MONITOR_SESSION:-$SESSION_NAME}" "$PROJECT_REPO_ROOT" "$PHASE_FILE" 2>/dev/null; then
-        agent_inject_into_session "${_MONITOR_SESSION:-$SESSION_NAME}" "$PROMPT"
-        log "Recovery session started"
-      else
-        log "ERROR: could not restart session after crash"
-      fi
-      ;;
-    PHASE:done|PHASE:failed|PHASE:needs_human|PHASE:merged)
-      agent_kill_session "${_MONITOR_SESSION:-$SESSION_NAME}"
-      ;;
-  esac
-}
-
-monitor_phase_loop "$PHASE_FILE" 7200 "planner_phase_callback"
+monitor_phase_loop "$PHASE_FILE" 7200 "formula_phase_callback"
 
 FINAL_PHASE=$(read_phase "$PHASE_FILE")
 log "Final phase: ${FINAL_PHASE:-none}"