Files
watermarks-remover/service/scripts
Guillaume Meyer (The Opinionated Man)andGitHub 8318d4df79 feat: iterative detection-guided Layer B rewriting (--candidates x --max-loops) (#153)
* feat: add reproducible SynthID-text removal benchmark

bench_synthid_text.py orchestrates the existing Layer B machinery into a
controlled, shareable experiment: generate watermarked + unwatermarked
samples with the MarkLLM SynthID scheme, run removal variants (strength x
candidates) plus controls (no-removal, Layer-A-only, optional re-stamp),
and report clear rate, score suppression, quality, and cost (tokens,
wall time, USD) with a clears-per-MTok efficiency ratio.

Emits report.md / results.json / results.csv with the exact reproduction
command and pinned commits; optional Gemini official-detector tier when
WATERMARKS_GEMINI_API_KEY is set. Mock-based tests, no torch in CI.

* docs: add README section on running the SynthID-text benchmark

Explains what LLM performs the Layer B rewrite (an external model configured
via WATERMARKS_REWRITE_* env vars or --rewrite-* flags; MarkLLM's opt-1.3b is
only the watermark generator/detector) and how to run a benchmark with Ollama
or an OpenAI-compatible endpoint, plus the non-origin-model re-stamp caveat.

* fix: honor WATERMARKS_REWRITE_ALLOW_REMOTE in the SynthID-text benchmark

The --rewrite-allow-remote flag now defaults from the env var (matching
rewrite_text.py and the other WATERMARKS_REWRITE_* settings), so a
non-loopback rewrite endpoint works after sourcing .env without an extra
flag.

* fix: MarkLLM sparse checkout and deps for the SynthID harness

- setup_markllm.sh sparse-checkout omitted '/visualize/', which
  watermark/base.py imports at module load — every scheme (incl. SynthID)
  failed with 'No module named visualize' during generation/detection.
- requirements-markllm.txt omitted scikit-learn, imported by the SynthID
  detector (watermark/synthid/detector_bayesian_torch.py).

Both broke the MarkLLM harness at runtime; the benchmark's sanity gate then
excluded every sample, producing empty per-variant results.

* fix: drop 4 GiB RLIMIT_AS on benchmark subprocesses

_run_cmd applied the common child RLIMIT_AS (default 4 GiB) via
subprocess_preexec_fn to every MarkLLM/rewrite child. torch needs a much
larger address space: CUDA init failed with 'out of memory' at
cudaGetDeviceCount and the 5.2 GB fp32 opt-1.3b could not load, so every
sample was excluded at generation. text_detectors.py already applies no
address-space cap to MarkLLM by default; the benchmark now matches.

* perf: keep MarkLLM resident via a serve worker (624 cold starts -> 1)

The benchmark spawned a fresh torch + opt-1.3b process per operation
(~60-90s each); a full run needs ~624 of them. detect_text_watermark.py
gains a 'serve' mode (JSON-lines over stdin/stdout, ready handshake) that
loads the model once; bench_synthid_text.py uses it via MarkLLMWorker with
automatic fallback to one-shot subprocesses (--no-worker to force).
Turns ~8h runs into ~40-60min.

* perf: skip per-candidate Gemini detections in rewrite subprocess

* feat: run the SynthID-text benchmark from the wr-markllm compose service

- Dockerfile.markllm: add '/visualize/' to the sparse checkout (same fix as
  setup_markllm.sh) and COPY the benchmark + rewrite scripts (stdlib-only).
- compose.yaml: wr-markllm gets the WATERMARKS_REWRITE_* and
  WATERMARKS_GEMINI_* env wiring, a bench-out volume for --out-dir, and a
  read-only mount of the bundled corpus (build context is service/, so the
  corpus cannot be COPY'd).
- docs: docker compose run example.

Note: the image ships CPU torch by design, so the container path is for
portability/CI; GPU runs use the host setup_markllm.sh venv.

* feat: per-sample progress logging in the benchmark

The persistent worker returns samples in-memory, so nothing is written
until the end of a run — runs looked stuck. eprint a [gen i/N] line per
generated sample and a [removal] summary per sample.

* chore: migrate Gemini config to gemini-3.6-flash; document SynthID-text retirement

Google retired SynthID text watermarking on the Generative Language API
(Aug 2026): text output is no longer watermarked and DETECT_TEXT_WATERMARK
is rejected on current 3.x models (confirmed by Google AI staff). Migrate
the default detection model to gemini-3.6-flash, document the retirement
in vendor-notes.md and the benchmark report caveat, and keep the detector
seam fail-soft until a vendor endpoint (e.g. Vertex AI) returns.

* feat: remove gemini-synthid-text detector (Google retired text watermarking)

Google removed SynthID text watermarking from the Generative Language API
(Aug 2026): text output is no longer watermarked and DETECT_TEXT_WATERMARK
is rejected on current 3.x models, so the vendor detector had nothing to
detect. Remove GeminiSynthIDTextDetector and its wiring:

- text_detectors.py: drop the Gemini class, HTTP helpers, and constants;
  keep MarkLLM + Claude seams (registry now markllm + claude-text).
- server.py / rewrite_text.py: per-candidate detection now triggers on
  --markllm-scheme only.
- bench_synthid_text.py: remove the Gemini tier (before/after, report
  table, --no-gemini flag); report caveat notes the retirement.
- configs/docs: drop WATERMARKS_GEMINI_* from .env.example / compose /
  README / SKILL.md / vendor-notes.md; keep the retirement note.
- tests: gemini tests removed or converted to MarkLLM (mocked subprocess).
- Dockerfile.markllm: parameterize BASE_IMAGE + TORCH_INDEX_URL so a GPU/
  arm64 image can be built (used for the --gpus all benchmark run).

* feat: iterative detection-guided Layer B rewriting (default 3 attempts)

Layer B (rewrite_text.py) now rewrites iteratively and stops as soon as an
attempt passes watermark evaluation:

- --candidates defaults to 3 (WATERMARKS_REWRITE_CANDIDATES); each attempt is
  one rewrite + one evaluation, and the loop exits on the first attempt the
  evaluator reports as not watermarked.
- Evaluator priority: MarkLLM same-config detection (when --markllm-scheme is
  passed) > bigram-Jaccard lexical divergence (fallback; no verdict, all
  attempts generated, most diverged selected). A vendor-detector seam is
  reserved ahead of MarkLLM for a future SynthID-text endpoint (Google retired
  text watermarking on its API in Aug 2026).
- Best-effort fallback when the max is exhausted: the lowest-score attempt is
  returned with a note; detector errors are fail-soft and never fail the
  rewrite.
- --json-stats now reports evaluator / attempts_made / passed and per-attempt
  candidate_scores records (passed, evaluation); markllm before/after/cleared
  is unchanged and the selected attempt's verdict is reused (no duplicate
  MarkLLM detection).

Benchmark (bench_synthid_text.py):

- --variants default becomes paraphrase:3 (candidates = max attempts).
- Rows/report/CSV carry attempts per document (mean_attempts, att column;
  attempts / evaluator / passed columns).

Tests, README, docs/synthid-text-benchmark.md and .env.example updated; 490
tests pass, ruff clean.

* feat: split rewrite attempts into --candidates x --max-loops (defaults 1 x 1)

Follow-up to the iterative Layer B rewrite: separate "variants per round"
from "evaluation rounds", so the retry loop is explicit and defaults stay
conservative.

- rewrite_text.py: --candidates (WATERMARKS_REWRITE_CANDIDATES) is now the
  number of variants generated per loop iteration (default 1); new
  --max-loops (WATERMARKS_REWRITE_LOOPS) caps the evaluation rounds (default
  1) -- each round generates --candidates variants and stops as soon as one
  passes, so raising --max-loops retries new variants until an evaluation
  passes. Stats now report max_loops and per-attempt records carry the loop
  index.
- bench_synthid_text.py: new --rewrite-loops flag (default 1) passed through
  to --max-loops.
- README / docs / .env.example updated; tests cover the 1x1 defaults, loop
  retry until pass, and cross-loop exhaustion.

* feat: MarkLLM serve worker over loopback TCP (WATERMARKS_MARKLLM_PORT)

detect_text_watermark.py serve can now also listen on a loopback TCP port,
and MarkLLMTextDetector reuses a resident worker when
WATERMARKS_MARKLLM_PORT is set (falls back to a one-shot subprocess when the
worker is unreachable). This avoids a ~20s torch+model cold start per detect
for callers that run a worker out-of-band.

Tests: loopback worker protocol + detector worker-port routing (mock-based).

* ci: add macOS runner to the test matrix
2026-08-18 18:28:19 -07:00
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