@5301/Fvg Delta Crypto Engine

FVG-Delta Crypto Signal Engine — Agent / Maintainer Guide (v5.5)

This is the single source of truth for any AI agent or engineer taking over this project. Read it fully before touching app.py. It explains the strategy, the code workflow, every bug that was fixed in this revision, the current state, and the rules for updating the app and its docs safely.

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1. What the app is

A production-style FastAPI service that scans MEXC UST-M perpetual futures on closed 15-minute candles, runs a strict Smart-Money-Concept (SMC) staged state machine, draws annotated chart screenshots, sends Telegram alerts for the late stages, and serves a live auto-updating dashboard with an in-memory Trade History. It is hosted on Hugging Face Spaces (Docker SDK).

Single file does almost everything: app.py. Everything else is config/docs/entrypoints.

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2. The strategy (must preserve)

The engine hunts the classic SMC continuation sequence. A setup walks forward through five stages and is never allowed to skip or silently regress:

Key rules baked into the code (do not weaken without explicit user request):

• Closed candles only. bars[-1] (forming) is never used for decisions. The

most recent closed candle is bars[-2] (last_closed = len(bars) - 2).

• FVG must be clean for Stage 1 & 2. If any candle enters the FVG before the

liquidity sweep, the textbook order is broken → invalidate. Only Stage 3 & 4 involve FVG interaction.

• Close through the FVG against the setup = invalidation. This applies before

Stage 1 (waiting), during Stage 1–3, and specifically at Stage 3 a close back through the FVG (a "Stage-3 invalidation") means the setup must never be promoted to Stage 4.

• Only NEW opportunities. A confirmation whose SL/TP have already played out

in history is discarded (freshness gate) — it is not surfaced and not recorded.

• Lock-forward indices. Each transition's bar index is searched once and

stored on the SetupState (bos_break_idx, stage2_break_idx, fvg_interaction_idx, locked liquidity/BoS). Subsequent cycles only look for the next transition, so stages don't flicker on transient empty scans.

Dynamic SL / TP (v5.5)

• SL sits a little past the FVG far edge (z.low for LONG, z.high for

SHORT) plus SL_FVG_BUFFER_ATR. If a recent order-block / body swing sits just beyond the FVG within OB_MAX_DISTANCE_ATR (default 1.0×ATR), the SL anchors to that instead — but it is never placed far from the FVG. Floors (MIN_STOP_ATR_MULT, MIN_STOP_PCT) stop a single candle from instant-stopping.

• Risk R = max(structural, MIN_STOP_ATR_MULT·ATR, entry·MIN_STOP_PCT/100).
• TP2 = farther of TP2_RR·R (default 3R) and the nearest resting liquidity /

opposing swing beyond entry (TP_SWING_LOOKBACK). target_source records which.

• TP1 = midpoint between entry and TP2 (50% of the target distance).
• Breakeven is a real outcome: once TP1 prints, the user moves SL to entry, so

if price returns to entry after TP1 the trade resolves as Breakeven (TP1 then entry) (see _sequential_outcome).

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3. Code workflow (how a scan cycle flows)

scanner_loop()                      # every SCAN_INTERVAL_SECONDS
  └─ picks = shard rotation + every active (stage>=1) symbol
       └─ process_symbol(symbol)
            ├─ load_bars()                      # MEXC kline (gzip/deflate; brotli installed)
            ├─ evaluate_stages(st)              # THE state machine (see below)
            ├─ record_stage4_open()             # when a FRESH stage 4 first appears
            ├─ _stage4_expired() -> close_stage4_trade()   # SL/TP2/breakeven -> history
            └─ maybe_send_stage_alerts()        # Stage 3 & 4 Telegram (photo first, then text)

evaluate_stages(st) order of operations: 1. Acquire a zone via detect_latest_zone() if none (impulse + FVG quality gates). 2. TTL / max-age expiry. 3. Hard invalidation: close through FVG against the setup (stages 1–3). 4. _lock_first_liquidity() — locks first retracement liquidity + immutable BoS level (impulse wick extreme) once. 5. Stage 1 (BoS close), Stage 2 (liquidity sweep, with premature-FVG-touch invalidation), Stage 3 (FVG interaction), Stage 4 (confirmation candle). 6. Stage-3 close-through invalidation guard before any Stage-4 promotion. 7. Freshness gate: discard already-played-out confirmations. 8. final_stage = desired_stage (sequential, monotonic via locked indices).

Charts: draw_chart() (live state) and draw_trade_chart() (closed-trade snapshot from a stored history row). BoS is drawn as a horizontal line at the impulse wick extreme from the anchor candle to the breaking candle, with a diamond on the anchor and an arrow on the break candle. FVG box is anchored to the gap candle (fvg_idx - 1).

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4. What was broken and what this revision fixed

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5. Current state

• Engine: rebuilt, lock-forward, sequential. Verified against live MEXC data:

zones detected, stages advance, fresh Stage-4 setups produce correct FVG-anchored SL and 3R/liquidity TP2, and resolve to SL / TP2 / breakeven in Trade History.

• Stage-4 is intentionally selective: at any single instant a brand-new

confirmation (entry candle = latest closed candle, nothing played out yet) is rare, so a static snapshot may show few/none. Over a continuous live session the engine accumulates them and writes Trade History on expiry.

• Trade History is in-memory only (TRADE_HISTORY deque, session-scoped,

wiped on restart). No disk persistence — the HF Spaces FS is ephemeral/read-only.

• Dashboard redesigned: animated gradient/grid background, radar logo with sweep,

minimal header (logo, title, one-line description, tags, "Version 5.5 Active"), compact metric cards, compact tables that fit to width on desktop and scroll on mobile, in-place live refresh via /api/state (no page reload).

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6. Important code map

app.py
  CFG (env config)                 ~line 48   ← all tunables; add new ones here
  Candle / Zone / SetupState / Stats          dataclasses
  _sequential_outcome()                       ← order-aware SL/TP2/breakeven
  _stage4_expired()                           ← terminal resolution (SL/TP2/BE)
  record_stage4_open / close_stage4_trade     ← Trade History lifecycle
  detect_latest_zone()                        ← impulse + FVG quality gates
  _lock_first_liquidity()                     ← locks liquidity + BoS extreme
  build_trade_levels()                        ← dynamic SL/TP (FVG-anchored)
  _levels_already_hit()                       ← freshness gate
  evaluate_stages()                           ← THE state machine
  draw_chart / draw_trade_chart()             ← matplotlib overlays
  maybe_send_stage_alerts()                   ← Telegram (stage 3 & 4 only)
  process_symbol / scanner_loop()             ← orchestration
  api_state()  ~line 1515                     ← live JSON (sends ALL active states)
  dashboard() ~line 1607                      ← HTML/CSS/JS (f-string)

Other files: preflight_check.py, requirements.txt, start.sh, run_one_shot.sh, README.md (HF metadata block is immutable), STRATEGY_DETAILED_SPEC.txt, VARIABLES_AND_SECRETS_GUIDE.txt.

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7. Rules for updating the app (do not break it)

1. Never alter the README metadata block (first --- … second ---). Hugging Face uses it for hosting. Copy it byte-for-byte on any rewrite. 2. The dashboard HTML is a Python f-string. Every literal { or } in CSS/JS must be doubled ({{ / }}). After editing, run python3 -c "import ast; ast.parse(open('app.py').read())" and grep the rendered HTML for stray single braces / typos before shipping. 3. Keep element IDs stable. The live JS targets last-scan, m-symbols, m-scanned, m-zones, m-stage1-count…m-stage4-count, m-invalidations, c-stage1…c-stage4, c-trades, rows-stage1…rows-stage4, rows-trades, rows-alerts, rows-events. Removing an ID is safe (JS guards with if(el)), but renaming a still-referenced one breaks live update. 4. `/api/state` must keep returning every stage≥1 symbol. Do not re-introduce a small slice cap on states or live rows will disappear again. 5. Closed candles only. Use bars[-2] / last_closed. Never decide on bars[-1]. 6. Don't add disk persistence for Trade History (HF FS is ephemeral/read-only). 7. Preserve stage strictness: sequential, no skipping, FVG clean for 1&2, close-through = invalidation, freshness gate for stage 4. If you must tune sensitivity, prefer CFG env vars over hard-coding. 8. Add new tunables to `CFG` (with an env override and a sane default) and document them in VARIABLES_AND_SECRETS_GUIDE.txt. 9. Test before shipping: python preflight_check.py, then a short live boot (uvicorn app:app) and hit /health, /api/state, /, /api/chart.png.

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8. Rules for updating the docs

Whenever you change behavior, update all of these in the same change so they never drift:

• AGENT.md (this file) — add the symptom→cause→fix row and any new rule.
• STRATEGY_DETAILED_SPEC.txt — exact strategy/stage/level behavior.
• VARIABLES_AND_SECRETS_GUIDE.txt — any new/changed env var, with example values.
• README.md — user-facing summary (never touch the metadata block).

Write explanations with concrete examples (worked numbers / a sample symbol), matching the style already in those files.

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9. Deploy notes (Hugging Face Spaces)

• Docker SDK. Container runs start.sh → preflight_check.py → uvicorn app:app

on $PORT (default 7860).

• Required secrets: TELEGRAM_BOT_TOKEN, TELEGRAM_CHAT_ID. Without them the UI

still runs; Telegram alerts are skipped and logged.

• Tunables are all env vars (see the variables guide). Defaults are production-safe.