Agent Playbook: Autonomous Real-World Purchases via ADB + Bazos.cz

Date: 2026-02-19 Bead: beads-hub-sl1 GitHub Issue: #31 Status: Proven in production (DDR4 RAM purchase, 2026-02-19)

1. Overview

This playbook documents how an AI agent can autonomously complete a real-world purchase on Bazos.cz (Czech classifieds platform) using:

• Browser automation for web interactions (phone reveal, verification)
• ADB (Android Debug Bridge) for SMS read/write on a paired Android device
• Agent reasoning for negotiation, logistics lookup, and payment generation

End-to-end flow time: ~40 minutes (including seller response wait times)

2. Architecture

┌─────────────────────────────────────────────────┐
│                   AI Agent                       │
│  (OpenClaw / Claude / any LLM orchestrator)     │
├─────────────┬───────────────┬───────────────────┤
│  Browser    │  ADB Bridge   │  Web Fetch        │
│  Control    │  (USB/TCP)    │  (HTTP client)    │
│             │               │                   │
│  bazos.cz   │  Samsung SMS  │  zasilkovna.cz    │
│  subdomain  │  app via UI   │  pickup points    │
│  navigation │  automation   │  bank QR gen      │
└─────────────┴───────────────┴───────────────────┘
        │              │               │
   Phone reveal   Read/Send SMS   Logistics &
   Verification   Negotiation     Payment

Components

3. Complete Purchase Flow

Phase 1: Get Seller Phone Number

1. Navigate to listing on correct subdomain (e.g., pc.bazos.cz)
2. Trigger phone reveal: document.querySelector('.teldetail').click()
3. Enter agent phone number in overlay and submit
4. Read verification SMS via ADB UI dump (see §4)
5. Enter verification code in overlay → receive seller phone number

Phase 2: Initial Contact (SMS)

6. Compose SMS via ADB to seller number
7. Send inquiry — express interest, ask about shipping/availability
8. Monitor for seller reply via ADB UI dumps

Phase 3: Negotiation

9. Read seller reply — parse shipping terms, price confirmation
10. Send follow-up — confirm price, request bank details and shipping info
11. Handle seller questions — provide name, email, pickup point as needed

Phase 4: Logistics

12. Look up pickup point (e.g., Zásilkovna) via web fetch
13. Send logistics details to seller via SMS

Phase 5: Payment

14. Receive bank account from seller (Czech format: XXXXXXXXXX/BBBB)
15. Convert to IBAN and generate SPD payment QR code
16. Present QR to human for approval and payment ← HUMAN GATE
17. Send payment confirmation SMS to seller after human confirms

4. ADB Interaction Patterns

4.1 Reading SMS (UI Dump Method)

Samsung devices block content://sms queries and SQLite access without root. The reliable method is UI automation:

# Dump current UI state
adb -s $DEVICE shell uiautomator dump /sdcard/ui.xml
adb -s $DEVICE pull /sdcard/ui.xml /tmp/ui.xml

# Extract all visible text
grep -o 'text="[^"]*"' /tmp/ui.xml | grep -v 'text=""'

To navigate to a specific SMS thread:

1. Open Messages app: adb -s $DEVICE shell am start -n com.samsung.android.messaging/.ui.ConversationListActivity
2. Dump UI to find the target thread row
3. Calculate tap coordinates from bounds attribute (center of bounding box)
4. Tap: adb -s $DEVICE shell input tap X Y

4.2 Sending SMS

# ALWAYS force-stop first to get clean compose window
adb -s $DEVICE shell am force-stop com.samsung.android.messaging
sleep 1

# Open fresh compose to target number
adb -s $DEVICE shell 'am start -a android.intent.action.SENDTO -d "smsto:+420XXXXXXXXX"'
sleep 2

# Type word-by-word (spaces are eaten by `input text`)
for word in "Hello," "I" "am" "interested."; do
  adb -s $DEVICE shell input text "$word"
  adb -s $DEVICE shell input keyevent KEYCODE_SPACE
done

# Dismiss keyboard BEFORE tapping Send
adb -s $DEVICE shell input keyevent KEYCODE_BACK
sleep 1

# Find Send button via UI dump, tap its bounds center
adb -s $DEVICE shell uiautomator dump /sdcard/ui.xml
# Parse for content-desc="Send", extract bounds, tap center
adb -s $DEVICE shell input tap $SEND_X $SEND_Y

4.3 Verifying Send Success

adb -s $DEVICE shell uiautomator dump /sdcard/ui.xml
# Check compose field — empty means sent
grep 'editor_body' /tmp/ui.xml | grep -o 'text="[^"]*"'
# text="" → success | text="..." → still in compose, retry

4.4 Coordinate Systems — Critical

• UI dump bounds = touch coordinate space ← USE THESE
• Screenshot pixels ≠ touch coordinates on Samsung
• Check touch space: adb shell wm size (e.g., 1080x1920)
• Never derive tap coordinates from screenshot pixel positions

5. Bazos.cz Platform Specifics

Subdomain Scoping

• Verification is per-subdomain — verifying on www.bazos.cz does NOT work for pc.bazos.cz
• Always verify on the same subdomain as the listing
• Codes expire quickly — complete the flow without navigating away

Phone Reveal DOM Selectors

// Trigger overlay
document.querySelector('.teldetail').click()

// Enter phone/code
document.querySelector('#overlaytel input[type=text]').value = 'VALUE'
document.querySelector('#overlaytel button').click()

// Read result
document.querySelector('#overlaytel').innerText

6. Czech Payment QR Generation

Czech banks use the SPD (Short Payment Descriptor) format.

Account Number → IBAN Conversion

def czech_account_to_iban(account: str, bank_code: str, prefix: str = '000000') -> str:
    padded = prefix.zfill(6) + account.zfill(10)
    bban = bank_code + padded
    rearranged = bban + '1235' + '00'  # CZ = 12,35
    check = 98 - (int(rearranged) % 97)
    return f'CZ{check:02d}{bban}'

SPD QR String

SPD*1.0*ACC:CZ{IBAN}*AM:{AMOUNT}*CC:CZK*MSG:{MESSAGE}

Generate a QR code from this string and present to the human for scanning with their banking app.

7. Security Considerations

7.1 Human-in-the-Loop Gates

7.2 ADB Security

• Device authentication: ADB requires prior USB debugging authorization (device-level trust)
• Network exposure: Use USB connection, NOT adb tcpip over network (exposes device to LAN)
• Scope limitation: Agent should only interact with SMS app — no contacts, no file access, no app installs
• Credential isolation: Agent phone number is separate from human’s personal number

7.3 Data Handling

• No persistent storage of seller phone numbers or bank details after transaction completes
• SMS content should be processed in-memory, not logged to disk
• Redact phone numbers and account numbers in any logs or memory files

7.4 Anti-Abuse

• Rate limiting: Max 1 SMS per 30 seconds to avoid carrier spam flags
• Verification cooldown: Bazos may throttle repeated phone verifications — respect delays
• No automated bulk purchasing — this playbook is for single, intentional purchases

8. Known Pitfalls

9. Proof-of-Concept Outline

A minimal PoC consists of three scripts:

bazos_phone_reveal.py

• Input: Bazos listing URL, agent phone number, ADB device ID
• Flow: Browser → trigger overlay → enter phone → read SMS via ADB → enter code → return seller phone
• Output: Seller phone number

adb_sms.sh

• Functions: send_sms(device, number, message), read_thread(device, contact_name)
• Handles: force-stop, word-by-word typing, keyboard dismiss, send verification

purchase_orchestrator.py

• Input: Listing URL, budget, shipping preference
• Orchestrates: phone reveal → SMS negotiation loop → logistics lookup → payment QR generation
• Human gate: Presents QR, waits for confirmation before sending payment confirmation SMS

10. Future Improvements

• OCR fallback: Screenshot + OCR when UI dump fails to capture dynamic content
• Multi-device support: Route SMS through different devices based on carrier/region
• Conversation memory: Track multi-turn negotiations across sessions
• Auto-retry with backoff: Handle transient ADB connection drops
• Platform expansion: Adapt patterns for other Czech classifieds (Sbazar, Facebook Marketplace)

This playbook is based on a successful real-world purchase completed on 2026-02-19. All techniques were validated against a Samsung device running Samsung Messages.