M6 + M0: hardening, deploy docs, PoC scripts

- Pipeline-down fallback: dialplan plays gogo-fallback after a failed AudioSocket (§15) + script to synthesize the Bosnian prompt via TTS - Voice heartbeat file → /health/voice endpoint + live status in admin panel - Retention job also purges stale call registrations; chat sessions metered; 100%-usage super-admin alert email (GOGO_ADMIN_ALERT_EMAIL) - .env.example, docs/DEPLOY.md (compose stack, GPU node, backups pg_dump, update procedure, security notes) - §16 Definition of Done as an automated test: softphone-style call → fake partner availability → request pushed → webhook confirm → console SMS - M0 PoC scripts: STT accuracy harness (CER/WER + spoken-digit check; dry-run verified with espeak-ng samples + faster-whisper small on CPU — phone number extracted exactly), TTS bake-off (Azure vs ElevenLabs, latency+cost), and end-to-end latency smoke test speaking real AudioSocket to the live pipeline Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-11 11:27:05 +02:00
parent de5a2abdeb
commit fd45ff84dc
16 changed files with 733 additions and 5 deletions
--- a/.env.example
+++ b/.env.example
@@ -0,0 +1,46 @@
+# Gogo Telefon — copy to .env and fill in. All variables are prefixed GOGO_.
+
+# Core
+GOGO_ENV=prod
+GOGO_SECRET_KEY=change-me-long-random-string        # sessions, action links, secret encryption
+GOGO_BASE_URL=https://app.gogotelefon.ba            # public URL (action links, transcripts, widget)
+GOGO_DATABASE_URL=postgresql+psycopg://gogo:gogo@db:5432/gogo
+GOGO_INTERNAL_TOKEN=change-me-dialplan-token        # Asterisk dialplan ↔ backend
+
+# LLM (agent)
+GOGO_ANTHROPIC_API_KEY=sk-ant-...
+GOGO_LLM_MODEL=claude-haiku-4-5-20251001
+
+# TTS — one of the two (default decided by the Phase-0 bake-off)
+GOGO_TTS_PROVIDER=azure                             # azure | elevenlabs
+GOGO_AZURE_SPEECH_KEY=
+GOGO_AZURE_SPEECH_REGION=westeurope
+GOGO_ELEVENLABS_API_KEY=
+
+# STT (voice service)
+GOGO_WHISPER_MODEL=large-v3                         # small for CPU dev
+GOGO_WHISPER_DEVICE=cuda                            # cuda | cpu | auto
+
+# Email (proposal emails to owners)
+GOGO_EMAIL_PROVIDER=smtp                            # console for dev
+GOGO_SMTP_HOST=mail.example.ba
+GOGO_SMTP_PORT=587
+GOGO_SMTP_USER=
+GOGO_SMTP_PASSWORD=
+GOGO_EMAIL_FROM="Gogo Telefon <noreply@gogotelefon.ba>"
+GOGO_ADMIN_ALERT_EMAIL=                             # super-admin alerts (100% usage)
+
+# SMS (via GSM gateway, M5; console logs SMS in dev)
+GOGO_SMS_PROVIDER=console                           # console | gsm_gateway
+GOGO_GSM_GATEWAY_URL=http://192.168.1.50
+GOGO_GSM_GATEWAY_USER=admin
+GOGO_GSM_GATEWAY_PASSWORD=
+
+# Google Calendar OAuth (free/busy read-only, §8.1)
+GOGO_GOOGLE_CLIENT_ID=
+GOGO_GOOGLE_CLIENT_SECRET=
+
+# Voice pipeline
+GOGO_VOICE_PORT=9092
+GOGO_RECORDINGS_DIR=/data/recordings
+GOGO_AUDIO_RETENTION_DAYS=90
--- a/README.md
+++ b/README.md
@@ -53,3 +53,22 @@ the **reference implementation of Appendix B** for partner IT teams:
 | `tests/fake_partner.py` | Appendix B reference implementation |

 All code/comments in English; all client- and owner-facing text in Bosnian (Latin).
+
+## Status (software phase complete)
+
+| Milestone | State |
+|---|---|
+| M0 PoC scripts (STT/TTS/latency) | ✅ written + dry-run; real numbers need founder recordings + API keys |
+| M1 backend core + proposal engine | ✅ |
+| M2 agent in text mode | ✅ (Appendix-A acceptance tests run when an Anthropic key is set) |
+| M3 widget + dashboard + super-admin | ✅ verified live in browser |
+| M4 voice pipeline (softphone path) | ✅ incl. real-Asterisk config validation |
+| M5 hardware layer (GSM/SMS/forwarding) | ✅ written + mock-tested; live runbook in `docs/HARDWARE_TESTING.md` |
+| M6 hardening + deploy | ✅ `docs/DEPLOY.md` |
+
+The §16 Definition of Done is an automated test: `tests/test_definition_of_done.py`.
+
+Still needed from the founder: Anthropic API key, TTS key (Azure/ElevenLabs
+bake-off via `scripts/poc/tts_bakeoff.py`), speech samples for
+`scripts/poc/stt_test.py`, GSM gateway hardware + SIMs, Google OAuth client
+(for Calendar tenants), SMTP account.
--- a/docs/DEPLOY.md
+++ b/docs/DEPLOY.md
@@ -0,0 +1,95 @@
+# Deploy — founder's DC (Docker Compose, §3/§16 M6)
+
+## Layout
+
+| Service | What | Where |
+|---|---|---|
+| `db` | PostgreSQL 16 | any node |
+| `app` | FastAPI backend (dashboard, admin, widget, webhooks, action links) | any node |
+| `voice` | AudioSocket server + Whisper STT | **GPU node** |
+| `asterisk` | SIP server (softphones, GSM gateway) | host networking, reachable by the gateway |
+
+## First install
+
+```bash
+git clone <repo> && cd gogotelefon
+cp .env.example .env            # fill everything in; strong GOGO_SECRET_KEY!
+docker compose build
+docker compose up -d db app     # app runs alembic upgrade head on start
+docker compose --profile voice up -d voice
+
+# Asterisk config comes from the DB:
+docker compose exec app python -m gogo.telephony.asterisk --out ./asterisk/conf \
+    --backend http://app:8000 --voice voice:9092
+python scripts/generate_fallback_audio.py ./asterisk/sounds   # needs a TTS key
+docker compose --profile voice up -d asterisk
+
+# seed the first admin (or python -m gogo.seed for a full demo tenant):
+docker compose exec app python - <<'EOF'
+import asyncio
+from gogo.auth import hash_password
+from gogo.db import get_sessionmaker
+from gogo.models import Admin
+async def main():
+    async with get_sessionmaker()() as s:
+        s.add(Admin(email="you@gogotelefon.ba", password_hash=hash_password("CHANGE-ME")))
+        await s.commit()
+asyncio.run(main())
+EOF
+```
+
+Put a TLS reverse proxy (caddy/nginx) in front of `app:8000` for
+`GOGO_BASE_URL` — action links and the widget are public.
+
+## GPU node for Whisper
+
+`Dockerfile.voice` installs CPU wheels by default. On the GPU node use the
+NVIDIA runtime and set `GOGO_WHISPER_DEVICE=cuda`, `GOGO_WHISPER_MODEL=large-v3`
+(one RTX 4090/L4 handles 10–15 concurrent calls, §3). Scale by adding voice
+containers and pointing different tenants' Asterisk `GOGO_VOICE` at them.
+
+## Operational jobs (built-in, APScheduler in `app`)
+
+- proposal expiry + owner reminders — every 5 min
+- partner polling fallback — every 5 min
+- retention: delete call audio older than `GOGO_AUDIO_RETENTION_DAYS`
+  (transcripts kept, §5.4), purge stale call registrations — daily 04:00
+
+## Monitoring
+
+- `GET /health` (app), `GET /health/db`, `GET /health/voice` (heartbeat age)
+- admin panel → *Sistem*: DB, LLM key, email/SMS mode, voice heartbeat,
+  delivery errors from `sms_log`/`email_log`
+- per-call latency breakdown: `calls.trace.turns[].{stt_ms,llm_ms}`
+
+## Backups
+
+```bash
+# nightly dump (cron on the DB node) — keep 14 days
+docker compose exec -T db pg_dump -U gogo gogo | gzip > /backup/gogo-$(date +%F).sql.gz
+find /backup -name 'gogo-*.sql.gz' -mtime +14 -delete
+```
+
+Recordings volume: rsync `/data/recordings` if call audio must survive node
+loss (transcripts are in the DB either way; audio expires after 90 days).
+
+Restore: `gunzip -c dump.sql.gz | docker compose exec -T db psql -U gogo gogo`.
+
+## Update procedure
+
+```bash
+git pull
+docker compose build app voice
+docker compose up -d app voice        # alembic migrates on app start
+# if workers/tenants changed the SIP layout:
+docker compose exec app python -m gogo.telephony.asterisk --out ./asterisk/conf ...
+docker compose exec asterisk asterisk -rx 'core reload'
+```
+
+## Security notes
+
+- OAuth tokens + partner API keys are encrypted at rest (Fernet from
+  `GOGO_SECRET_KEY`) — changing the key orphans them (reconnect/re-enter).
+- `/internal/*` must not be exposed publicly (compose keeps it on the
+  internal network; the reverse proxy should only forward what's needed).
+- Action links are signed + single-use; widget is rate-limited per IP.
--- a/gogo/admin/router.py
+++ b/gogo/admin/router.py
@@ -772,8 +772,20 @@ async def health_page(
            {"at": row.at, "kind": f"SMS/{row.kind}", "to": row.to_msisdn, "error": row.error}
        )

-    # voice pipeline heartbeat (written by the M4 pipeline service)
-    voice_status, voice_badge = "nije pokrenut (M4)", "pending"
+    # voice pipeline heartbeat (written by the voice service, M6)
+    import os
+    import time as time_mod
+
+    from gogo.voice.server import heartbeat_path
+
+    try:
+        age = time_mod.time() - os.path.getmtime(heartbeat_path())
+        if age <= 60:
+            voice_status, voice_badge = f"radi (heartbeat prije {int(age)}s)", "confirmed"
+        else:
+            voice_status, voice_badge = f"NE RADI (heartbeat star {int(age)}s)", "rejected"
+    except OSError:
+        voice_status, voice_badge = "nije pokrenut", "pending"

    return templates.TemplateResponse(
        request,
--- a/gogo/api/health.py
+++ b/gogo/api/health.py
@@ -21,3 +21,21 @@ async def health():
 async def health_db(session: AsyncSession = Depends(get_session)):
    await session.execute(text("SELECT 1"))
    return {"status": "ok"}
+
+
+@router.get("/health/voice")
+async def health_voice():
+    """Voice pipeline liveness via its heartbeat file (shared volume)."""
+    import os
+    import time
+
+    from gogo.voice.server import heartbeat_path
+
+    path = heartbeat_path()
+    try:
+        age = time.time() - os.path.getmtime(path)
+    except OSError:
+        return {"status": "down", "detail": "no heartbeat file"}
+    if age > 60:
+        return {"status": "down", "detail": f"heartbeat {int(age)}s old"}
+    return {"status": "ok", "heartbeat_age_s": int(age)}
--- a/gogo/chat/router.py
+++ b/gogo/chat/router.py
@@ -191,5 +191,8 @@ async def _resume_or_create(
        outcome="abandoned",  # upgraded as the conversation progresses
    )
    session.add(chat)
+    from gogo.metering import record_chat_session
+
+    await record_chat_session(session, tenant.id)
    await session.commit()
    return chat, []
--- a/gogo/config.py
+++ b/gogo/config.py
@@ -22,6 +22,7 @@ class Settings(BaseSettings):
    smtp_password: str = ""
    smtp_starttls: bool = True
    email_from: str = "Gogo Telefon <noreply@gogotelefon.ba>"
+    admin_alert_email: str = ""  # super-admin alerts (100% usage etc.), empty = off

    # SMS. provider=console logs instead of sending (GSM gateway impl in M5).
    sms_provider: str = "console"  # console | gsm_gateway
--- a/gogo/jobs.py
+++ b/gogo/jobs.py
@@ -97,6 +97,16 @@ async def run_retention_job() -> None:
                    log.exception("failed to delete recording %s", path)
                    continue
            call.recording_path = None
+
+        # drop stale dialplan handoff rows (they are only needed for minutes)
+        from sqlalchemy import delete
+
+        from gogo.models import CallRegistration
+
+        reg_cutoff = datetime.now(UTC) - timedelta(days=7)
+        await session.execute(
+            delete(CallRegistration).where(CallRegistration.created_at < reg_cutoff)
+        )
        await session.commit()
        if rows:
            log.info("retention: cleared %d recordings", len(rows))
--- a/gogo/metering.py
+++ b/gogo/metering.py
@@ -61,6 +61,7 @@ async def record_agent_call(
            tenant.slug, used // 60, tenant.included_minutes,
        )
        await _send_warning(session, tenant, used // 60, 100)
+        await _alert_admin(tenant, used // 60)
    elif used >= included_s * 0.8 and not counter.warned_80:
        counter.warned_80 = True
        await _send_warning(session, tenant, used // 60, 80)
@@ -75,6 +76,28 @@ async def _send_warning(session: AsyncSession, tenant: Tenant, used_minutes: int
        log.exception("usage warning email failed (tenant %s)", tenant.slug)


+async def _alert_admin(tenant: Tenant, used_minutes: int) -> None:
+    """100% soft-limit hit → alert the super-admin for an upsell conversation (§12)."""
+    from gogo.config import get_settings
+    from gogo.email import EmailMessage, send_email
+
+    to = get_settings().admin_alert_email
+    if not to:
+        return
+    try:
+        await send_email(
+            EmailMessage(
+                [to],
+                f"[Gogo] {tenant.name} prešao 100% minuta ({used_minutes} min)",
+                f"Salon {tenant.name} ({tenant.slug}) je prešao uključene minute "
+                f"({used_minutes}/{tenant.included_minutes}). Asistent i dalje odgovara "
+                "(hard cutoff je isključen) — vrijeme za razgovor o većem paketu.",
+            )
+        )
+    except Exception:  # noqa: BLE001
+        log.exception("admin alert email failed")
+
+
 async def record_sms(session: AsyncSession, tenant_id: uuid.UUID) -> None:
    counter = await get_counter(session, tenant_id)
    counter.sms_sent += 1
--- a/gogo/telephony/asterisk.py
+++ b/gogo/telephony/asterisk.py
@@ -156,6 +156,9 @@ exten => _[+0-9].,1,NoOp(Gogo inbound ${{EXTEN}} for {slug})
 same => n,Dial(${{TARGETS}},${{RINGTIME}})
 same => n,GotoIf($["${{DIALSTATUS}}"="ANSWER"]?answered)
 same => n(agent),AudioSocket(${{GOGO_UUID}},${{GOGO_VOICE}})
+ ; if the voice pipeline is down AudioSocket fails instantly → fallback (§15);
+ ; after a normal agent call the caller is gone and Playback is a no-op
+ same => n,Playback(gogo-fallback)
 same => n,Hangup()
 same => n(answered),Set(RES=${{CURL(${{GOGO_BACKEND}}/internal/calls/${{GOGO_UUID}}/answered?token=${{GOGO_TOKEN}}&duration=${{CDR(billsec)}})}})
 same => n,Hangup()
--- a/gogo/voice/server.py
+++ b/gogo/voice/server.py
@@ -94,14 +94,38 @@ async def handle_connection(reader: asyncio.StreamReader, writer: asyncio.Stream
    await session.run()


+async def _heartbeat() -> None:
+    """Touch a heartbeat file every 15 s; /health/voice + admin panel read its age (M6)."""
+    import os
+
+    path = heartbeat_path()
+    os.makedirs(os.path.dirname(path), exist_ok=True)
+    while True:
+        try:
+            with open(path, "w") as f:
+                f.write(str(int(asyncio.get_running_loop().time())))
+        except OSError:
+            log.exception("cannot write heartbeat %s", path)
+        await asyncio.sleep(15)
+
+
+def heartbeat_path() -> str:
+    import os
+
+    return os.path.join(get_settings().recordings_dir, ".voice-heartbeat")
+
+
 async def serve() -> None:
    s = get_settings()
    server = await asyncio.start_server(handle_connection, s.voice_host, s.voice_port)
    addrs = ", ".join(str(sock.getsockname()) for sock in server.sockets)
    log.info("AudioSocket server listening on %s", addrs)
-    # health heartbeat file for the admin panel / monitoring (M6)
-    async with server:
-        await server.serve_forever()
+    heartbeat = asyncio.create_task(_heartbeat())
+    try:
+        async with server:
+            await server.serve_forever()
+    finally:
+        heartbeat.cancel()


 def main() -> None:
--- a/scripts/generate_fallback_audio.py
+++ b/scripts/generate_fallback_audio.py
@@ -0,0 +1,36 @@
+"""Generate the Asterisk fallback prompt 'gogo-fallback' (§15) — played when the
+voice pipeline is unreachable. Uses the configured TTS provider.
+
+Run:  python scripts/generate_fallback_audio.py [asterisk-sounds-dir]
+Then place gogo-fallback.wav into Asterisk's sounds dir (or mount it in compose).
+"""
+
+from __future__ import annotations
+
+import asyncio
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+
+from gogo.voice.audio import pcm_to_wav  # noqa: E402
+from gogo.voice.tts import make_tts  # noqa: E402
+
+TEXT = (
+    "Poštovani, trenutno nismo u mogućnosti primiti vaš poziv. "
+    "Molimo pozovite kasnije, ili posjetite našu web stranicu. Hvala i prijatno!"
+)
+
+
+async def main() -> None:
+    out_dir = Path(sys.argv[1] if len(sys.argv) > 1 else "./asterisk/sounds")
+    out_dir.mkdir(parents=True, exist_ok=True)
+    tts, voice = make_tts()
+    pcm = await tts.synthesize(TEXT, voice)
+    path = out_dir / "gogo-fallback.wav"
+    path.write_bytes(pcm_to_wav(pcm))
+    print(f"wrote {path} ({len(pcm) // 16} ms)")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())
--- a/scripts/poc/latency_smoke.py
+++ b/scripts/poc/latency_smoke.py
@@ -0,0 +1,127 @@
+"""M0 PoC #3 — end-to-end latency smoke test (§14 Phase 0).
+
+Measures mouth-to-ear response time through the REAL pipeline: connects to the
+running AudioSocket voice server exactly like Asterisk would, plays a recorded
+utterance (or a tone with --fake providers), and measures the gap between
+end-of-utterance and the first agent audio frame of the reply.
+
+Target (§15): < 1.5 s, worst case < 2.5 s. GATE: > 2.5 s → rethink providers.
+
+Setup:
+    1. backend + voice server running (see docs/VOICE_TESTING.md)
+    2. a CallRegistration for the demo tenant is created automatically here
+
+Run:  python scripts/poc/latency_smoke.py [utterance.wav] [--host 127.0.0.1] [--port 9092]
+"""
+
+from __future__ import annotations
+
+import asyncio
+import sys
+import time
+import wave
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[2]))
+
+from sqlalchemy import select  # noqa: E402
+
+from gogo.db import get_sessionmaker  # noqa: E402
+from gogo.models import CallRegistration, Tenant  # noqa: E402
+from gogo.voice.audio import FRAME_BYTES, FRAME_MS, resample, silence, tone  # noqa: E402
+
+KIND_TERMINATE, KIND_UUID, KIND_AUDIO = 0x00, 0x01, 0x10
+
+
+def load_utterance(path: str | None) -> bytes:
+    if path:
+        with wave.open(path, "rb") as w:
+            pcm = w.readframes(w.getnframes())
+            if w.getframerate() != 8000:
+                pcm = resample(pcm, w.getframerate(), 8000)
+            return pcm
+    print("(no wav given — using a 1s tone; STT will hear nothing useful, "
+          "use a real recording for a true number)")
+    return tone(440, 1000)
+
+
+async def register_call() -> str:
+    async with get_sessionmaker()() as session:
+        tenant = (
+            await session.execute(select(Tenant).where(Tenant.slug == "salon-merima"))
+        ).scalar_one_or_none()
+        if tenant is None:
+            print("run `python -m gogo.seed` first")
+            sys.exit(1)
+        reg = CallRegistration(tenant_id=tenant.id, caller_msisdn="+38765123456")
+        session.add(reg)
+        await session.commit()
+        return str(reg.id)
+
+
+async def main() -> None:
+    args = [a for a in sys.argv[1:] if not a.startswith("--")]
+    host = sys.argv[sys.argv.index("--host") + 1] if "--host" in sys.argv else "127.0.0.1"
+    port = int(sys.argv[sys.argv.index("--port") + 1]) if "--port" in sys.argv else 9092
+
+    import uuid as uuid_mod
+
+    reg_id = uuid_mod.UUID(await register_call())
+    utterance = load_utterance(args[0] if args else None) + silence(800)
+
+    reader, writer = await asyncio.open_connection(host, port)
+    writer.write(bytes([KIND_UUID, 0, 16]) + reg_id.bytes)
+    await writer.drain()
+
+    async def read_msg():
+        header = await reader.readexactly(3)
+        length = int.from_bytes(header[1:3], "big")
+        payload = await reader.readexactly(length) if length else b""
+        return header[0], payload
+
+    # 1) greeting: time from handshake to first audio frame
+    t_start = time.monotonic()
+    kind, _ = await read_msg()
+    greeting_first_audio = time.monotonic() - t_start
+    print(f"greeting first audio after {greeting_first_audio * 1000:.0f} ms")
+
+    # drain the greeting while it plays (send silence like a real caller)
+    async def drain_audio(quiet_ms_needed: int = 600) -> None:
+        last_audio = time.monotonic()
+        while (time.monotonic() - last_audio) * 1000 < quiet_ms_needed:
+            try:
+                kind, _ = await asyncio.wait_for(read_msg(), timeout=0.05)
+                if kind == KIND_AUDIO:
+                    last_audio = time.monotonic()
+            except TimeoutError:
+                pass
+            writer.write(bytes([KIND_AUDIO]) + FRAME_BYTES.to_bytes(2, "big") + silence(FRAME_MS))
+            await writer.drain()
+            await asyncio.sleep(FRAME_MS / 1000)
+
+    await drain_audio()
+
+    # 2) speak the utterance paced like a phone, then measure to first reply frame
+    for i in range(0, len(utterance), FRAME_BYTES):
+        frame = utterance[i : i + FRAME_BYTES].ljust(FRAME_BYTES, b"\x00")
+        writer.write(bytes([KIND_AUDIO]) + len(frame).to_bytes(2, "big") + frame)
+        await writer.drain()
+        await asyncio.sleep(FRAME_MS / 1000)
+    t_end_of_speech = time.monotonic()
+
+    while True:
+        kind, payload = await read_msg()
+        if kind == KIND_AUDIO and payload.strip(b"\x00"):
+            break
+        if kind == KIND_TERMINATE:
+            print("server hung up before replying")
+            return
+    response_latency = time.monotonic() - t_end_of_speech
+    print(f"\nmouth-to-ear response latency: {response_latency * 1000:.0f} ms")
+    verdict = "OK ✓" if response_latency < 1.5 else ("worst-case ⚠" if response_latency < 2.5 else "FAIL ✗ — rethink providers (§14)")
+    print(f"target <1500 ms, worst case <2500 ms → {verdict}")
+    writer.close()
+
+
+if __name__ == "__main__":
+    asyncio.run(main())
--- a/scripts/poc/stt_test.py
+++ b/scripts/poc/stt_test.py
@@ -0,0 +1,112 @@
+"""M0 PoC #1 — STT accuracy on local speech samples (§14 Phase 0).
+
+Kill-the-risk test: can faster-whisper (language hint 'sr') reliably transcribe
+service names, personal names and PHONE NUMBERS SPOKEN ALOUD over phone-quality
+audio?
+
+Prepare a directory of WAV/MP3/OGG samples recorded by the founder + a
+manifest.csv with two columns:  filename,expected_text
+
+Run:
+    python scripts/poc/stt_test.py <samples_dir> [--model large-v3] [--device cuda]
+
+Outputs per-file transcript vs expected, character error rate (CER), word error
+rate (WER), digit accuracy (for phone numbers) and timing.
+GATE (§14): if phone numbers/names are unusable → stop and rethink providers.
+"""
+
+from __future__ import annotations
+
+import csv
+import re
+import sys
+import time
+from pathlib import Path
+
+
+def levenshtein(a: list, b: list) -> int:
+    prev = list(range(len(b) + 1))
+    for i, ca in enumerate(a, 1):
+        cur = [i]
+        for j, cb in enumerate(b, 1):
+            cur.append(min(prev[j] + 1, cur[j - 1] + 1, prev[j - 1] + (ca != cb)))
+        prev = cur
+    return prev[-1]
+
+
+def normalize(s: str) -> str:
+    return re.sub(r"[^\wšđčćž ]", "", s.lower()).strip()
+
+
+def digits(s: str) -> str:
+    words = {
+        "nula": "0", "jedan": "1", "dva": "2", "tri": "3", "četiri": "4",
+        "pet": "5", "šest": "6", "sedam": "7", "osam": "8", "devet": "9",
+    }
+    out = []
+    for token in normalize(s).split():
+        if token.isdigit():
+            out.append(token)
+        elif token in words:
+            out.append(words[token])
+    return "".join(out)
+
+
+def main() -> None:
+    if len(sys.argv) < 2:
+        print(__doc__)
+        sys.exit(1)
+    samples_dir = Path(sys.argv[1])
+    model_name = sys.argv[sys.argv.index("--model") + 1] if "--model" in sys.argv else "large-v3"
+    device = sys.argv[sys.argv.index("--device") + 1] if "--device" in sys.argv else "auto"
+
+    manifest = samples_dir / "manifest.csv"
+    if not manifest.exists():
+        print(f"missing {manifest} (columns: filename,expected_text)")
+        sys.exit(1)
+
+    from faster_whisper import WhisperModel
+
+    print(f"loading {model_name} on {device}…")
+    t0 = time.monotonic()
+    model = WhisperModel(model_name, device=device,
+                         compute_type="float16" if device == "cuda" else "int8")
+    print(f"model loaded in {time.monotonic() - t0:.1f}s\n")
+
+    rows = list(csv.DictReader(manifest.open()))
+    total_cer = total_wer = 0.0
+    digit_ok = digit_total = 0
+    for row in rows:
+        path = samples_dir / row["filename"]
+        expected = row["expected_text"]
+        t0 = time.monotonic()
+        segments, info = model.transcribe(str(path), language="sr", beam_size=5, vad_filter=True)
+        got = " ".join(s.text.strip() for s in segments).strip()
+        elapsed = time.monotonic() - t0
+
+        exp_n, got_n = normalize(expected), normalize(got)
+        cer = levenshtein(list(exp_n), list(got_n)) / max(1, len(exp_n))
+        wer = levenshtein(exp_n.split(), got_n.split()) / max(1, len(exp_n.split()))
+        total_cer += cer
+        total_wer += wer
+
+        exp_digits = digits(expected)
+        if exp_digits:
+            digit_total += 1
+            digit_ok += exp_digits == digits(got)
+
+        flag = "✓" if wer < 0.2 else ("~" if wer < 0.5 else "✗")
+        print(f"{flag} {row['filename']}  ({elapsed:.1f}s, audio {info.duration:.1f}s)")
+        print(f"   očekivano: {expected}")
+        print(f"   dobijeno : {got}\n")
+
+    n = max(1, len(rows))
+    print("=" * 60)
+    print(f"samples: {len(rows)}  avg CER: {total_cer / n:.1%}  avg WER: {total_wer / n:.1%}")
+    if digit_total:
+        print(f"phone-number samples exactly right: {digit_ok}/{digit_total}")
+    print("GATE: WER > 50% on names or wrong digits on most numbers → rethink STT (§14)")
+
+
+if __name__ == "__main__":
+    main()
--- a/scripts/poc/tts_bakeoff.py
+++ b/scripts/poc/tts_bakeoff.py
@@ -0,0 +1,82 @@
+"""M0 PoC #2 — TTS bake-off: Azure Neural vs ElevenLabs Flash (§14 Phase 0).
+
+Synthesizes typical agent sentences with every candidate voice, saves WAVs for
+the founder to listen to, and prints latency + rough per-character cost.
+
+Env: GOGO_AZURE_SPEECH_KEY / GOGO_AZURE_SPEECH_REGION and/or GOGO_ELEVENLABS_API_KEY.
+Run:  python scripts/poc/tts_bakeoff.py [out_dir]
+"""
+
+from __future__ import annotations
+
+import asyncio
+import sys
+import time
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[2]))
+
+from gogo.config import get_settings  # noqa: E402
+from gogo.voice.audio import pcm_to_wav  # noqa: E402
+from gogo.voice.tts import AzureTTS, ElevenLabsTTS  # noqa: E402
+
+SENTENCES = [
+    "Dobar dan, dobili ste salon Merima. Ja sam Gogo, virtuelni asistent — razgovor se snima. Kako vam mogu pomoći?",
+    "U srijedu poslijepodne slobodno je u dva i trideset ili u pet. Šta vam više odgovara?",
+    "Farbanje cijele dužine je od šezdeset do devedeset maraka, zavisno od dužine kose.",
+    "Važi. Na koje ime da zavedem zahtjev?",
+    "Prosljeđujem salonu zahtjev: šišanje i feniranje, srijeda u pet. Kontaktiraće vas u najkraćem roku radi potvrde. Hvala na pozivu i prijatno!",
+    "Izvinite, nisam vas dobro razumio. Možete li ponoviti?",
+]
+
+AZURE_VOICES = ["sr-RS-SophieNeural", "sr-RS-NicholasNeural", "hr-HR-GabrijelaNeural", "hr-HR-SreckoNeural"]
+ELEVEN_VOICES = ["JBFqnCBsd6RMkjVDRZzb"]  # replace with shortlisted hr/sr voices
+
+# rough public prices (2026): Azure Neural ~$15/1M chars, ElevenLabs Flash ~$50/1M chars
+COST_PER_CHAR_USD = {"azure": 15 / 1_000_000, "elevenlabs": 50 / 1_000_000}
+
+
+async def bake(provider_name: str, provider, voices: list[str], out: Path) -> None:
+    for voice in voices:
+        total_chars = total_ms = 0
+        for i, sentence in enumerate(SENTENCES, 1):
+            t0 = time.monotonic()
+            try:
+                pcm = await provider.synthesize(sentence, voice)
+            except Exception as e:  # noqa: BLE001
+                print(f"  {voice} #{i}: FAILED — {e}")
+                continue
+            ms = int((time.monotonic() - t0) * 1000)
+            total_chars += len(sentence)
+            total_ms += ms
+            path = out / f"{provider_name}-{voice.replace(':', '_')}-{i}.wav"
+            path.write_bytes(pcm_to_wav(pcm))
+            print(f"  {voice} #{i}: {ms} ms, {len(pcm) // 16} ms audio → {path.name}")
+        if total_chars:
+            cost = total_chars * COST_PER_CHAR_USD[provider_name]
+            print(
+                f"  {voice}: avg latency {total_ms // len(SENTENCES)} ms, "
+                f"~${cost:.4f} for all {total_chars} chars "
+                f"(~${cost / len(SENTENCES) * 1000:.3f} per 1000-char call)\n"
+            )
+
+
+async def main() -> None:
+    out = Path(sys.argv[1] if len(sys.argv) > 1 else "./poc-tts-out")
+    out.mkdir(parents=True, exist_ok=True)
+    s = get_settings()
+    if s.azure_speech_key:
+        print("== Azure Neural ==")
+        await bake("azure", AzureTTS(), AZURE_VOICES, out)
+    else:
+        print("(GOGO_AZURE_SPEECH_KEY not set — skipping Azure)")
+    if s.elevenlabs_api_key:
+        print("== ElevenLabs Flash ==")
+        await bake("elevenlabs", ElevenLabsTTS(), ELEVEN_VOICES, out)
+    else:
+        print("(GOGO_ELEVENLABS_API_KEY not set — skipping ElevenLabs)")
+    print(f"\nListen to the WAVs in {out}/ and pick 2–3 voices for the dashboard (§6.1).")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())
--- a/tests/test_definition_of_done.py
+++ b/tests/test_definition_of_done.py
@@ -0,0 +1,117 @@
+"""§16 Definition of Done, software phase:
+
+'a demo where a softphone call books a request end-to-end (agent conversation →
+availability from fake partner API → request pushed → webhook outcome →
+console-SMS logged) … all without any hardware present.'
+
+(The chat-widget + mock-tenant half lives in tests/test_chat_widget.py.)
+"""
+
+from sqlalchemy import select
+
+from gogo.agent.llm import LLMResponse, ScriptedLLM, ToolUse, set_llm
+from gogo.domain import BookingStatus
+from gogo.models import BookingRequest, Call, CallRegistration, Service
+from gogo.voice.call import CallLimits, CallSession
+from tests.fake_partner import staff_resolve
+from tests.test_voice import UTTERANCE, FakeCallerTransport, frames, voice_fakes  # noqa: F401
+
+SLOT = {"start": "2026-07-15T17:00:00+02:00", "end": "2026-07-15T17:45:00+02:00"}
+
+
+async def test_definition_of_done_voice_partner_flow(
+    session, partner_tenant, wire_fake_partner, gogo_client, emails, sms, voice_fakes  # noqa: F811
+):
+    stt, tts = voice_fakes
+    wire_fake_partner.slots["SRV-12"] = [SLOT]
+
+    svc = (
+        await session.execute(select(Service).where(Service.tenant_id == partner_tenant.id))
+    ).scalar_one()
+
+    # the "softphone caller" asks for a manicure; the agent checks availability
+    # against the partner API and pushes the booking request into it
+    stt.texts = ["Htjela bih manikir u srijedu, Amra Hodžić, broj s kojeg zovem."]
+    set_llm(
+        ScriptedLLM(
+            [
+                LLMResponse(
+                    text="",
+                    tool_uses=[
+                        ToolUse(
+                            id="t1",
+                            name="check_availability",
+                            input={
+                                "service_id": str(svc.id),
+                                "date_from": "2026-07-15",
+                                "date_to": "2026-07-15",
+                            },
+                        )
+                    ],
+                    stop_reason="tool_use",
+                ),
+                LLMResponse(
+                    text="",
+                    tool_uses=[
+                        ToolUse(
+                            id="t2",
+                            name="submit_booking_request",
+                            input={
+                                "service_id": str(svc.id),
+                                "service_name_raw": "manikir",
+                                "client_name": "Amra Hodžić",
+                                "client_phone": "+38765123456",
+                                "slots": [SLOT],
+                                "summary": "Manikir, srijeda u 17.",
+                            },
+                        )
+                    ],
+                    stop_reason="tool_use",
+                ),
+                LLMResponse(
+                    text="Prosljeđujem zahtjev salonu — kontaktiraće vas. Hvala i prijatno!"
+                ),
+            ]
+        )
+    )
+
+    reg = CallRegistration(tenant_id=partner_tenant.id, caller_msisdn="+38765123456")
+    session.add(reg)
+    await session.commit()
+    reg_id = reg.id
+
+    transport = FakeCallerTransport(UTTERANCE)
+    await CallSession(
+        transport, reg_id, pace=0, limits=CallLimits(inactivity_s=5, max_call_s=60)
+    ).run()
+    set_llm(None)
+
+    # 1) availability came from the fake partner, request was PUSHED into it
+    assert "REQ-0001" in wire_fake_partner.requests
+    pushed = wire_fake_partner.requests["REQ-0001"]
+    assert pushed["client"]["name"] == "Amra Hodžić"
+    assert pushed["service_id"] == "SRV-12"
+    assert pushed["source"] == "voice"
+    # partner tenants get no owner email by default (§8.2)
+    assert emails == []
+
+    # 2) salon staff confirm in their own software → webhook → Gogo closes + SMS
+    resp = await staff_resolve(
+        gogo_client, str(partner_tenant.id), "REQ-0001", "confirmed", confirmed_slot=SLOT
+    )
+    assert resp.status_code == 200
+
+    session.expire_all()
+    req = (await session.execute(select(BookingRequest))).scalar_one()
+    assert req.status == BookingStatus.confirmed.value
+
+    # 3) console-SMS logged to the client
+    assert len(sms) == 1
+    to, body = sms[0]
+    assert to == "+38765123456"
+    assert "Potvrđen termin" in body and "srijeda" in body
+
+    # 4) the call itself is fully accounted for
+    call = (await session.execute(select(Call))).scalar_one()
+    assert call.outcome == "request_created"
+    assert call.transcript and call.recording_path