diff --git a/.env.example b/.env.example
new file mode 100644
index 0000000..a208d84
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,86 @@
+# PromptPipe environment configuration
+# Copy this file to .env and edit as needed:
+#   cp .env.example .env
+#
+# Precedence: CLI flags > environment variables (.env) > defaults
+# See docs/configuration.md for the full reference.
+
+# --- Core ---
+
+# Base directory for SQLite files, debug logs, and lock file.
+# Default: /var/lib/promptpipe
+# PROMPTPIPE_STATE_DIR=/var/lib/promptpipe
+
+# HTTP server listen address.
+# Default: :8080
+# API_ADDR=:8080
+
+# --- Database ---
+
+# Application database DSN (SQLite or PostgreSQL).
+# Default: file:{STATE_DIR}/state.db?_foreign_keys=on
+# DATABASE_DSN=file:/var/lib/promptpipe/state.db?_foreign_keys=on
+# DATABASE_DSN=postgres://user:pass@localhost:5432/promptpipe?sslmode=disable
+
+# Legacy fallback for DATABASE_DSN (used only when DATABASE_DSN is unset).
+# DATABASE_URL=
+
+# WhatsApp/whatsmeow session database DSN.
+# Default: file:{STATE_DIR}/whatsmeow.db?_foreign_keys=on
+# WHATSAPP_DB_DSN=file:/var/lib/promptpipe/whatsmeow.db?_foreign_keys=on
+
+# --- GenAI (OpenAI) ---
+
+# Required for conversation flow and genai prompts.
+# OPENAI_API_KEY=
+
+# OpenAI model name.
+# Default: gpt-4o-mini
+# GENAI_MODEL=gpt-4o-mini
+
+# OpenAI temperature (0.0–1.0). Lower = more consistent.
+# Default: 0.1
+# GENAI_TEMPERATURE=0.1
+
+# --- Scheduling ---
+
+# Default cron string for /schedule when no schedule object is provided.
+# Five-field format: minute hour day month weekday
+# DEFAULT_SCHEDULE=
+
+# Minutes before scheduled habit time to send preparation message.
+# Default: 10
+# SCHEDULER_PREP_TIME_MINUTES=10
+
+# --- Conversation flow ---
+
+# System prompt file paths.
+# INTAKE_BOT_PROMPT_FILE=prompts/intake_bot_system.txt
+# PROMPT_GENERATOR_PROMPT_FILE=prompts/prompt_generator_system.txt
+# FEEDBACK_TRACKER_PROMPT_FILE=prompts/feedback_tracker_system.txt
+
+# Number of history messages sent to bot tools (-1=unlimited, 0=none).
+# Default: -1
+# CHAT_HISTORY_LIMIT=-1
+
+# Timeout for initial feedback response (e.g. "15m").
+# Default: 15m
+# FEEDBACK_INITIAL_TIMEOUT=15m
+
+# Delay before follow-up feedback session (e.g. "3h").
+# Default: 3h
+# FEEDBACK_FOLLOWUP_DELAY=3h
+
+# Auto-enter feedback mode after scheduled prompt inactivity.
+# Default: true
+# AUTO_FEEDBACK_AFTER_PROMPT_ENABLED=true
+
+# Auto-enroll unknown phone numbers on first message.
+# Default: false
+# AUTO_ENROLL_NEW_USERS=false
+
+# --- Debug ---
+
+# Enable debug messages and GenAI call logging.
+# Default: false
+# PROMPTPIPE_DEBUG=false
diff --git a/.jules/atlas.md b/.jules/atlas.md
new file mode 100644
index 0000000..3449938
--- /dev/null
+++ b/.jules/atlas.md
@@ -0,0 +1,5 @@
+## 2026-02-27 - Env var drift is the #1 documentation risk
+
+**Learning:** All 19 environment variables in `cmd/PromptPipe/main.go` were already correctly documented in `docs/configuration.md`, but there was no `.env.example` and no automated check to prevent future drift. Env vars are added via `os.Getenv`, `ParseBoolEnv`, `ParseIntEnv`, `ParseFloatEnv`, and `GetEnvWithDefault` — all easily grep-able.
+
+**Action:** Always run `make check-docs` (or `scripts/check-env-docs.sh`) after adding new env vars. The script extracts var names from main.go and verifies they appear in both `.env.example` and `docs/configuration.md`.
diff --git a/Makefile b/Makefile
index c8e6c04..38ee2cf 100644
--- a/Makefile
+++ b/Makefile
@@ -9,4 +9,7 @@ test-postgres:
 	@echo "Run with: POSTGRES_DSN_TEST='postgres://user:pass@host:5432/dbname?sslmode=disable' make test-postgres"
 	POSTGRES_DSN_TEST="$${POSTGRES_DSN_TEST}" go test ./internal/store/... -v -count=1
 
-.PHONY: build test test-postgres
+check-docs:
+	@bash scripts/check-env-docs.sh
+
+.PHONY: build test test-postgres check-docs
diff --git a/docs/configuration.md b/docs/configuration.md
index 2c478bb..79c68f6 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -6,6 +6,8 @@ PromptPipe loads configuration from environment variables and command-line flags
 2. `../.env`
 3. `../../.env`
 
+A ready-to-use template is available at [`.env.example`](../.env.example). Copy it to `.env` and uncomment the variables you need.
+
 ## Precedence
 
 1. **CLI flags**
diff --git a/docs/development.md b/docs/development.md
index cae1e87..9c5a105 100644
--- a/docs/development.md
+++ b/docs/development.md
@@ -4,6 +4,7 @@
 
 - Go **1.24.3+** (see `go.mod`)
 - Make (optional)
+- Docker & Docker Compose (optional, for running with PostgreSQL)
 
 ## Build
 
@@ -16,14 +17,69 @@ go build -o build/promptpipe cmd/PromptPipe/main.go
 ## Test
 
 ```bash
+make test
+# or
 go test ./...
+```
+
+Additional checks:
+
+```bash
 go vet ./...
+gofmt -d .
+```
+
+To run tests against PostgreSQL (requires a running Postgres instance):
+
+```bash
+POSTGRES_DSN_TEST='postgres://user:pass@localhost:5432/dbname?sslmode=disable' make test-postgres
+```
+
+## Configure
+
+Copy the example environment file and edit it:
+
+```bash
+cp .env.example .env
 ```
 
+At minimum, set `OPENAI_API_KEY` if you want GenAI / conversation features.
+See [`.env.example`](../.env.example) for all available variables and their defaults, or
+[Configuration](configuration.md) for the full reference.
+
+PromptPipe searches for `.env` files in `./.env`, `../.env`, and `../../.env` (first match wins).
+
 ## Run locally
 
+### Standalone (SQLite)
+
 ```bash
 ./build/promptpipe
 ```
 
-The server loads `.env` files from the repository root or parent directories if present (see [Configuration](configuration.md)).
+The API listens on `:8080` by default. Verify with:
+
+```bash
+curl http://localhost:8080/health
+```
+
+### With Docker Compose (PostgreSQL)
+
+The repository includes a `docker-compose.yml` that starts PromptPipe alongside PostgreSQL 16:
+
+```bash
+docker compose up -d
+```
+
+This exposes the API on the host port defined by `API_PORT` (default `8080`).
+To tear down while keeping data: `docker compose down`.
+To also remove volumes: `docker compose down -v`.
+
+## Verify documentation
+
+A drift-check script ensures `.env.example` and `docs/configuration.md` stay in sync with the
+environment variables actually read in `cmd/PromptPipe/main.go`:
+
+```bash
+make check-docs
+```
diff --git a/scripts/check-env-docs.sh b/scripts/check-env-docs.sh
new file mode 100755
index 0000000..0b975cc
--- /dev/null
+++ b/scripts/check-env-docs.sh
@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+# check-env-docs.sh — verify that every environment variable read in
+# cmd/PromptPipe/main.go is documented in .env.example and docs/configuration.md.
+#
+# Usage:  ./scripts/check-env-docs.sh          (run from repo root)
+#         make check-docs                       (via Makefile target)
+#
+# Exit code 0 = all env vars are documented.  Non-zero = drift detected.
+
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+MAIN_GO="$REPO_ROOT/cmd/PromptPipe/main.go"
+ENV_EXAMPLE="$REPO_ROOT/.env.example"
+CONFIG_DOC="$REPO_ROOT/docs/configuration.md"
+
+errors=0
+
+# Extract environment variable names from main.go.
+# Matches os.Getenv("VAR"), ParseBoolEnv("VAR", ...), ParseIntEnv("VAR", ...),
+# ParseFloatEnv("VAR", ...), and GetEnvWithDefault("VAR", ...).
+env_vars=$(grep -oP '(?:os\.Getenv|ParseBoolEnv|ParseIntEnv|ParseFloatEnv|GetEnvWithDefault)\(\s*"([A-Z_]+)"' "$MAIN_GO" \
+    | grep -oP '"[A-Z_]+"' \
+    | tr -d '"' \
+    | sort -u)
+
+echo "Env vars found in $MAIN_GO:"
+echo "$env_vars"
+echo ""
+
+for var in $env_vars; do
+    # Check .env.example
+    if ! grep -q "$var" "$ENV_EXAMPLE" 2>/dev/null; then
+        echo "DRIFT: $var is used in main.go but missing from .env.example"
+        errors=$((errors + 1))
+    fi
+    # Check docs/configuration.md
+    if ! grep -q "$var" "$CONFIG_DOC" 2>/dev/null; then
+        echo "DRIFT: $var is used in main.go but missing from docs/configuration.md"
+        errors=$((errors + 1))
+    fi
+done
+
+if [ "$errors" -gt 0 ]; then
+    echo ""
+    echo "❌ Found $errors documentation drift issue(s)."
+    echo "   Update .env.example and/or docs/configuration.md to match main.go."
+    exit 1
+fi
+
+echo "✅ All environment variables are documented."