diff --git a/benchmarks/run_benchmarks.py b/benchmarks/run_benchmarks.py
index 29c6266a..785c6bcd 100644
--- a/benchmarks/run_benchmarks.py
+++ b/benchmarks/run_benchmarks.py
@@ -316,6 +316,37 @@ def bench_realizer_coverage() -> BenchResult:
 # Runner
 # ---------------------------------------------------------------------------
 
+def bench_teaching_loop_determinism(runs: int = 10) -> BenchResult:
+    """Run propose → replay → accept N times; assert byte-identical artifacts.
+
+    This is the determinism benchmark for the *learning loop* itself
+    (ADR-0055..0057): per-fact provenance, replay-equivalence gate,
+    operator-gated corpus write — all replayable bit-identically.
+    The active corpus on disk is byte-identical pre/post.
+    """
+    from benchmarks.teaching_loop import run_teaching_loop_determinism
+
+    report = run_teaching_loop_determinism(runs=runs)
+    passed = report.deterministic and report.active_corpus_byte_identical
+    metric = 1.0 if passed else 0.0
+    detail = (
+        f"{report.runs} runs; unique(proposal_id)={report.unique_proposal_ids}, "
+        f"unique(baseline)={report.unique_replay_baselines}, "
+        f"unique(candidate)={report.unique_replay_candidates}, "
+        f"unique(chain_id)={report.unique_chain_ids}; "
+        f"mean={report.elapsed_mean_s:.3f}s p50={report.elapsed_p50_s:.3f}s "
+        f"p95={report.elapsed_p95_s:.3f}s; active_corpus_byte_eq="
+        f"{report.active_corpus_byte_identical}"
+    )
+    return BenchResult(
+        name="teaching_loop_determinism",
+        passed=passed,
+        metric=metric,
+        unit="byte_identity_ratio",
+        detail=detail,
+    )
+
+
 _SUITES: dict[str, list] = {
     "determinism": [bench_determinism],
     "latency": [bench_latency],
@@ -323,6 +354,7 @@ _SUITES: dict[str, list] = {
     "versor": [bench_versor_closure_audit],
     "convergence": [bench_convergence_proof],
     "realizer": [bench_realizer_coverage],
+    "teaching-loop": [bench_teaching_loop_determinism],
 }
 
 _ALL = [
@@ -349,6 +381,8 @@ def run_benchmarks(
     for func in funcs:
         if func is bench_determinism:
             result = func(runs=runs)
+        elif func is bench_teaching_loop_determinism:
+            result = func(runs=runs)
         else:
             result = func()
         report.results.append(result)
diff --git a/benchmarks/teaching_loop.py b/benchmarks/teaching_loop.py
new file mode 100644
index 00000000..c0dd9418
--- /dev/null
+++ b/benchmarks/teaching_loop.py
@@ -0,0 +1,222 @@
+"""Teaching-loop determinism benchmark.
+
+Run the full reviewed-corpus extension pipeline (propose → replay-
+equivalence gate → operator accept) N times against the same input.
+Assert byte-identical artifacts every run:
+
+  - proposal_id           (SHA-256 of canonical-JSON payload)
+  - replay baseline       (cognition lane metrics on active corpus)
+  - replay candidate      (cognition lane metrics on transient corpus)
+  - regressed_metrics     (sorted tuple)
+  - corpus_append_chain_id
+
+Also report latency:
+  - per-iteration wall-time (mean / p50 / p95)
+  - total wall-time
+
+Trust boundary: the benchmark writes ONLY to tempdir-scoped paths.
+The active teaching corpus on disk is byte-identical pre/post.
+Asserted in the report and in the test.
+"""
+
+from __future__ import annotations
+
+import shutil
+import statistics
+import tempfile
+import time
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any
+
+from chat import teaching_grounding as _tg
+from teaching.discovery import DiscoveryCandidate, EvidencePointer
+from teaching.proposals import (
+    ProposalLog,
+    accept_proposal,
+    propose_from_candidate,
+)
+
+
+# Canonical demo candidate — identical to the learning-loop demo's
+# operator-augmented payload.  Same input → same artifacts on every
+# iteration; that's the entire benchmark thesis.
+def _canonical_candidate() -> DiscoveryCandidate:
+    return DiscoveryCandidate(
+        candidate_id="bench_canonical_001",
+        proposed_chain={
+            "subject": "thought", "intent": "cause",
+            "connective": "reveals", "object": "meaning",
+        },
+        trigger="would_have_grounded",
+        source_turn_trace="",
+        pack_consistent=True,
+        boundary_clean=True,
+        polarity="affirms",
+        claim_domain="factual",
+        evidence=(
+            EvidencePointer(
+                source="corpus",
+                ref="cause_creation_reveals_meaning",
+                polarity="affirms",
+                epistemic_status="coherent",
+            ),
+        ),
+    )
+
+
+@dataclass(frozen=True, slots=True)
+class _IterationArtifact:
+    proposal_id: str
+    replay_baseline: tuple[tuple[str, float], ...]
+    replay_candidate: tuple[tuple[str, float], ...]
+    regressed_metrics: tuple[str, ...]
+    chain_id_written: str
+    elapsed_s: float
+
+
+@dataclass(frozen=True, slots=True)
+class TeachingLoopBenchReport:
+    runs: int
+    unique_proposal_ids: int
+    unique_replay_baselines: int
+    unique_replay_candidates: int
+    unique_regressed_metrics: int
+    unique_chain_ids: int
+    deterministic: bool
+    active_corpus_byte_identical: bool
+    elapsed_mean_s: float
+    elapsed_p50_s: float
+    elapsed_p95_s: float
+    elapsed_total_s: float
+    sample_proposal_id: str
+    sample_chain_id: str
+
+    def as_dict(self) -> dict[str, Any]:
+        return {
+            "runs": self.runs,
+            "unique_proposal_ids": self.unique_proposal_ids,
+            "unique_replay_baselines": self.unique_replay_baselines,
+            "unique_replay_candidates": self.unique_replay_candidates,
+            "unique_regressed_metrics": self.unique_regressed_metrics,
+            "unique_chain_ids": self.unique_chain_ids,
+            "deterministic": self.deterministic,
+            "active_corpus_byte_identical": self.active_corpus_byte_identical,
+            "elapsed_mean_s": round(self.elapsed_mean_s, 4),
+            "elapsed_p50_s": round(self.elapsed_p50_s, 4),
+            "elapsed_p95_s": round(self.elapsed_p95_s, 4),
+            "elapsed_total_s": round(self.elapsed_total_s, 4),
+            "sample_proposal_id": self.sample_proposal_id,
+            "sample_chain_id": self.sample_chain_id,
+        }
+
+
+def _freeze_metrics(d: dict[str, float]) -> tuple[tuple[str, float], ...]:
+    """Convert a metrics dict to a sorted tuple-of-pairs (hashable, ordered)."""
+    return tuple(sorted((k, round(float(v), 6)) for k, v in d.items()))
+
+
+def _percentile(values: list[float], pct: float) -> float:
+    """Inclusive percentile via linear interpolation.  Pure stdlib so
+    the bench has no numpy dependency on this path."""
+    if not values:
+        return 0.0
+    s = sorted(values)
+    if len(s) == 1:
+        return s[0]
+    k = (len(s) - 1) * pct / 100.0
+    lo, hi = int(k), min(int(k) + 1, len(s) - 1)
+    if lo == hi:
+        return s[lo]
+    return s[lo] + (s[hi] - s[lo]) * (k - lo)
+
+
+def run_teaching_loop_determinism(runs: int = 10) -> TeachingLoopBenchReport:
+    """Execute the full propose → replay → accept loop ``runs`` times
+    against the same candidate, then assert byte-identical artifacts.
+
+    Trust boundary: the active corpus is read once at the start and
+    once at the end; any byte difference is a defect.  All writes
+    are confined to tempdirs created inside this function.
+    """
+    active_path = _tg._CORPUS_PATH
+    active_bytes_before = active_path.read_bytes() if active_path.exists() else b""
+
+    artifacts: list[_IterationArtifact] = []
+    total_t0 = time.perf_counter()
+
+    for _ in range(runs):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            log_path = Path(tmpdir) / "proposals.jsonl"
+            transient = Path(tmpdir) / "cognition_chains_v1.jsonl"
+            if active_path.exists():
+                shutil.copyfile(active_path, transient)
+            else:
+                transient.write_text("", encoding="utf-8")
+
+            log = ProposalLog(log_path)
+            candidate = _canonical_candidate()
+
+            t0 = time.perf_counter()
+            proposal = propose_from_candidate(candidate, log=log)
+            rec = log.find(proposal.proposal_id) or {}
+            ev = rec.get("replay_evidence") or {}
+
+            chain_id = accept_proposal(
+                proposal.proposal_id, log=log,
+                corpus_path=transient,
+                review_date="2026-05-18",
+                operator_note="bench",
+            )
+            elapsed = time.perf_counter() - t0
+
+            artifacts.append(_IterationArtifact(
+                proposal_id=proposal.proposal_id,
+                replay_baseline=_freeze_metrics(ev.get("baseline", {})),
+                replay_candidate=_freeze_metrics(ev.get("candidate", {})),
+                regressed_metrics=tuple(ev.get("regressed_metrics") or ()),
+                chain_id_written=chain_id,
+                elapsed_s=elapsed,
+            ))
+
+    elapsed_total = time.perf_counter() - total_t0
+    elapsed_values = [a.elapsed_s for a in artifacts]
+
+    active_bytes_after = active_path.read_bytes() if active_path.exists() else b""
+
+    unique_pids = len({a.proposal_id for a in artifacts})
+    unique_baselines = len({a.replay_baseline for a in artifacts})
+    unique_candidates = len({a.replay_candidate for a in artifacts})
+    unique_regressed = len({a.regressed_metrics for a in artifacts})
+    unique_chain_ids = len({a.chain_id_written for a in artifacts})
+
+    deterministic = (
+        unique_pids == 1
+        and unique_baselines == 1
+        and unique_candidates == 1
+        and unique_regressed == 1
+        and unique_chain_ids == 1
+    )
+
+    return TeachingLoopBenchReport(
+        runs=runs,
+        unique_proposal_ids=unique_pids,
+        unique_replay_baselines=unique_baselines,
+        unique_replay_candidates=unique_candidates,
+        unique_regressed_metrics=unique_regressed,
+        unique_chain_ids=unique_chain_ids,
+        deterministic=deterministic,
+        active_corpus_byte_identical=(active_bytes_before == active_bytes_after),
+        elapsed_mean_s=statistics.mean(elapsed_values) if elapsed_values else 0.0,
+        elapsed_p50_s=_percentile(elapsed_values, 50.0),
+        elapsed_p95_s=_percentile(elapsed_values, 95.0),
+        elapsed_total_s=elapsed_total,
+        sample_proposal_id=artifacts[0].proposal_id if artifacts else "",
+        sample_chain_id=artifacts[0].chain_id_written if artifacts else "",
+    )
+
+
+__all__ = [
+    "TeachingLoopBenchReport",
+    "run_teaching_loop_determinism",
+]
diff --git a/core/cli.py b/core/cli.py
index d79e2574..ed9255b5 100644
--- a/core/cli.py
+++ b/core/cli.py
@@ -1777,7 +1777,7 @@ def build_parser() -> argparse.ArgumentParser:
         help="run benchmark harness (determinism, latency, speedup, versor audit)",
         description="run benchmark harness",
     )
-    bench.add_argument("--suite", choices=["determinism", "latency", "speedup", "versor", "convergence", "realizer", "cost"],
+    bench.add_argument("--suite", choices=["determinism", "latency", "speedup", "versor", "convergence", "realizer", "cost", "teaching-loop"],
                        help="run a specific benchmark suite")
     bench.add_argument("--runs", type=int, default=20, metavar="N", help="run count for determinism benchmark (also turns count for cost suite)")
     bench.add_argument("--json", action="store_true", help="emit machine-readable JSON")
diff --git a/tests/test_teaching_loop_bench.py b/tests/test_teaching_loop_bench.py
new file mode 100644
index 00000000..65b9349b
--- /dev/null
+++ b/tests/test_teaching_loop_bench.py
@@ -0,0 +1,57 @@
+"""Teaching-loop determinism benchmark — falsifiable claim test.
+
+The bench itself runs at any N ≥ 1; the test pins the headline claim
+at a low N for fast CI.  Headline claim:
+
+  "N identical inputs produce N byte-identical proposal artifacts,
+   the active corpus is byte-identical pre/post, and the wall-time
+   distribution is well-formed."
+
+If determinism breaks anywhere in the pipeline (proposal_id hashing,
+replay-equivalence gate, accept-side corpus_append, ProposalLog
+replay), at least one of the ``unique_*`` counts in the bench report
+will exceed 1 and this test fails.
+"""
+
+from __future__ import annotations
+
+from benchmarks.teaching_loop import run_teaching_loop_determinism
+
+
+def test_teaching_loop_is_deterministic_across_three_runs() -> None:
+    report = run_teaching_loop_determinism(runs=3)
+    assert report.deterministic is True
+    assert report.active_corpus_byte_identical is True
+    assert report.unique_proposal_ids == 1
+    assert report.unique_replay_baselines == 1
+    assert report.unique_replay_candidates == 1
+    assert report.unique_regressed_metrics == 1
+    assert report.unique_chain_ids == 1
+
+
+def test_proposal_id_is_a_sha256_prefix() -> None:
+    report = run_teaching_loop_determinism(runs=2)
+    pid = report.sample_proposal_id
+    assert len(pid) == 32
+    assert all(c in "0123456789abcdef" for c in pid)
+
+
+def test_chain_id_matches_canonical_layout() -> None:
+    report = run_teaching_loop_determinism(runs=2)
+    assert report.sample_chain_id == "cause_thought_reveals_meaning"
+
+
+def test_latency_stats_are_well_formed() -> None:
+    report = run_teaching_loop_determinism(runs=3)
+    assert report.elapsed_mean_s > 0.0
+    assert report.elapsed_p50_s > 0.0
+    assert report.elapsed_p95_s >= report.elapsed_p50_s
+    assert report.elapsed_total_s >= report.elapsed_mean_s * report.runs * 0.9
+
+
+def test_report_serialises_to_json() -> None:
+    import json
+    report = run_teaching_loop_determinism(runs=2)
+    blob = json.dumps(report.as_dict(), sort_keys=True)
+    assert "deterministic" in blob
+    assert "active_corpus_byte_identical" in blob