diff --git a/.github/workflows/csi-encoder-training.yml b/.github/workflows/csi-encoder-training.yml
index 034ae1216..211ea79cc 100644
--- a/.github/workflows/csi-encoder-training.yml
+++ b/.github/workflows/csi-encoder-training.yml
@@ -8,6 +8,7 @@ on:
       - 'scripts/train-espfi.py'
       - 'scripts/improve-espfi.py'
       - 'scripts/improve-espfi-kernel.py'
+      - 'scripts/improve-espfi-blend.py'
       - 'scripts/requirements-espfi-training.txt'
       - 'scripts/requirements-csi-training.txt'
       - 'scripts/tests/test_csi_training*.py'
diff --git a/docs/espfi-model-optimization.md b/docs/espfi-model-optimization.md
index b7f313de1..b9e220efc 100644
--- a/docs/espfi-model-optimization.md
+++ b/docs/espfi-model-optimization.md
@@ -284,3 +284,52 @@ are retained; the replay is verification, not independent accuracy evidence.
 Decision: retain the small spectral model and archive the nonlinear model
 as an accuracy experiment. No deployed model is replaced, no final-test
 arrays were evaluated, and neither candidate establishes SOTA.
+
+
+## Rejected blend and lossless seed encoding
+
+A frozen five-weight blend combined the preceding spectral ridge and RFF
+candidates using raw regression scores. Training-only mean fold macro F1
+selected equal weights (0.323484), but development macro F1 fell to 0.348261,
+with activities 3 and 7 still at zero F1. Accuracy was 30/70. The reproduced
+controls matched the previous development scores exactly: spectral 0.366065
+and RFF 0.383999. The blend is rejected; its complete receipt remains available.
+No other development weights were evaluated or substituted after selection.
+
+```sh
+python scripts/improve-espfi-blend.py \\
+  --manifest /private/espfi/prepared/manifest.json \\
+  --output /private/espfi/blend-001
+```
+
+The separate seed encoding changes only the representation of the fixed RFF
+projection. It stores 1,967 fitted and preprocessing scalars, then regenerates
+60,032 random-map scalars from seed 42 at load. Both regenerated arrays must
+match the exact export hashes before inference. Unexpected generator behavior,
+tampered model bytes, invalid shapes and nonfinite state fail closed.
+
+```python
+from csi_training.espfi_kernel import KernelBundle
+from csi_training.espfi_seeded import export_seeded, SeededKernelBundle
+parent = KernelBundle('/private/espfi/kernel-001-verified')
+export_seeded(parent.state, '/private/espfi/seeded-001')
+model = SeededKernelBundle('/private/espfi/seeded-001')
+logits = model.predict(amplitudes)
+```
+
+MEASURED on the ruOS CPU executor: weight bytes decreased from 496,488 to
+16,088 (96.76%); required metadata adds 913 bytes. All 70 development logits
+were exactly identical, maximum absolute error zero. Median loading time over
+30 loads was 1.948925 ms. Runtime state remains 61,999 float64 scalars, so this
+is a storage and distribution improvement, not RAM or sensing speed reduction.
+The separate parity receipt binds parent model digest and dataset provenance.
+The RFF candidate still has two zero-F1 activities and is not deployment ready.
+
+This round used a different CPU host. In a paired 500-call comparison on that
+host, float64 spectral, RFF and blend p50 latencies were 0.352430, 0.443975 and
+0.804585 ms. These timings cannot be compared directly with prior-host timings
+or with the prior float32 spectral deployment artifact.
+
+The earlier security workflow fails on preexisting Rust dependency alerts in
+unchanged `v2/Cargo.lock`; the Python checks pass. That remains a release gate,
+alongside independent room/person confirmation. No SOTA or promotion claim.
diff --git a/scripts/csi_training/espfi_blend.py b/scripts/csi_training/espfi_blend.py
new file mode 100644
index 000000000..7e62fa6b7
--- /dev/null
+++ b/scripts/csi_training/espfi_blend.py
@@ -0,0 +1,123 @@
+"""Frozen five-weight CSI ensemble experiment. Development evidence only."""
+import argparse
+import json
+from pathlib import Path
+import time
+import numpy as np
+from safetensors.numpy import save_file, load_file
+from .espfi import load_development
+from .espfi_generalize import features, folds
+from .espfi_kernel import fit, predict_features
+from .espfi_train import scores, digest, write_json
+
+WEIGHTS = (0., .25, .5, .75, 1.)
+COMPONENTS = (
+    {'family': 'relative_spectral', 'kind': 'linear', 'alpha': 10.},
+    {'family': 'relative_combined', 'kind': 'rff', 'dimensions': 128,
+     'gamma_multiplier': .1, 'alpha': .01})
+CONTRACT = {'weights': list(WEIGHTS), 'components': list(COMPONENTS),
+            'seed': 42, 'selection': 'mean training-fold macro F1 then smaller RFF weight',
+            'mix': '(1-w)*spectral_scores + w*RFF_scores; no softmax',
+            'test_access': False, 'promotionAuthorized': False}
+
+def select_weight(fold_predictions, labels):
+    results = []
+    for weight in WEIGHTS:
+        evaluations = [scores(y, ((1-weight)*a + weight*b).argmax(1), 7)
+                       for (a, b), y in zip(fold_predictions, labels)]
+        results.append({'weight': weight, 'folds': evaluations,
+                        'mean_macro_f1': float(np.mean([e['macro_f1'] for e in evaluations]))})
+    return max(results, key=lambda r: (r['mean_macro_f1'], -r['weight'])), results
+
+def infer(states, weight, amplitudes):
+    result = None
+    for index, coefficient in ((0, 1-weight), (1, weight)):
+        if coefficient:
+            value = coefficient * predict_features(states[index], features(amplitudes, COMPONENTS[index]['family']))
+            result = value if result is None else result + value
+    if result is None or not np.isfinite(result).all():
+        raise ValueError('Invalid ensemble output')
+    return result
+
+def run(parts, provenance, output):
+    if set(parts) != {'train', 'validation'}:
+        raise ValueError('Development partitions only')
+    root = Path(output)
+    root.mkdir(parents=True, exist_ok=False)
+    write_json(root/'status.json', {'status': 'running', 'promotionAuthorized': False})
+    write_json(root/'contract.json', CONTRACT)
+    start = time.monotonic()
+    try:
+        train, dev = parts['train'], parts['validation']
+        y = train['y']
+        fold_ids = folds(train['identity'], y)
+        cache = [features(train['x'], c['family']) for c in COMPONENTS]
+        predictions, labels = [], []
+        for fit_ids, eval_ids in fold_ids:
+            pair = []
+            for x, candidate in zip(cache, COMPONENTS):
+                state = fit(x[fit_ids], y[fit_ids], candidate)
+                pair.append(predict_features(state, x[eval_ids]))
+            predictions.append(pair)
+            labels.append(y[eval_ids])
+        selected, results = select_weight(predictions, labels)
+        write_json(root/'selection.json', {'selected': selected, 'candidates': results})
+        # Selection is frozen before using any external development signal.
+        weight = selected['weight']
+        states = [fit(x, y, c) for x, c in zip(cache, COMPONENTS)]
+        active = [i for i, coefficient in ((0, 1-weight), (1, weight)) if coefficient]
+        tensors = {str(i)+'__'+k: np.ascontiguousarray(v)
+                   for i in active for k, v in states[i].items()}
+        save_file(tensors, str(root/'model.safetensors'))
+        restored = load_file(str(root/'model.safetensors'))
+        restored_states = [{k.split('__', 1)[1]: v for k, v in restored.items()
+                            if k.startswith(str(i)+'__')} for i in range(2)]
+        before = infer(states, weight, dev['x'])
+        after = infer(restored_states, weight, dev['x'])
+        if not np.array_equal(before, after):
+            raise ValueError('Export parity failed')
+        metrics = {name: scores(dev['y'], infer(states, w, dev['x']).argmax(1), 7)
+                   for name, w in (('spectral_control', 0.), ('rff_control', 1.), ('selected', weight))}
+        timings = {name: [] for name in metrics}
+        choices = [('spectral_control', 0.), ('rff_control', 1.), ('selected', weight)]
+        for _ in range(20):
+            for _, w in choices:
+                infer(states, w, dev['x'][:1])
+        for repeat in range(500):
+            order = choices[repeat % 3:] + choices[:repeat % 3]
+            for name, w in order:
+                tick = time.perf_counter_ns()
+                infer(states, w, dev['x'][:1])
+                timings[name].append((time.perf_counter_ns()-tick)/1e6)
+        report = {'status': 'complete', 'promotionAuthorized': False,
+                  'evidence': provenance.get('evidence', 'MEASURED'),
+                  'contract': CONTRACT, 'selected': selected, 'candidates': results,
+                  'development': metrics, 'provenance': provenance,
+                  'model_sha256': digest(root/'model.safetensors'),
+                  'model_bytes': (root/'model.safetensors').stat().st_size,
+                  'implementation_sha256': digest(__file__),
+                  'dependency_sha256': {name: digest(Path(__file__).with_name(name))
+                      for name in ('espfi_kernel.py', 'espfi_generalize.py', 'espfi.py', 'espfi_train.py')},
+                  'reload_exact': True, 'active_components': active,
+                  'latency': {name: {'p50_ms': float(np.percentile(t, 50)),
+                                    'p95_ms': float(np.percentile(t, 95))} for name, t in timings.items()},
+                  'timing_scope': '500 rotated CPU batch1 calls including feature extraction and checks; excludes intake and temporal pooling',
+                  'elapsed_seconds': time.monotonic()-start,
+                  'limitations': ['Repeatedly used development set; not independent confirmation',
+                                  'No final test evaluation or SOTA evidence',
+                                  'Controls reproduced in float64 on this executor; not prior float32 deployment timing']}
+        write_json(root/'metrics.json', report)
+        write_json(root/'status.json', {'status': 'complete', 'promotionAuthorized': False})
+        return report
+    except Exception:
+        write_json(root/'status.json', {'status': 'failed', 'promotionAuthorized': False})
+        raise
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--manifest', required=True)
+    parser.add_argument('--output', required=True)
+    args = parser.parse_args()
+    parts, provenance = load_development(args.manifest)
+    report = run(parts, provenance, args.output)
+    print(json.dumps({k: report[k] for k in ('selected', 'development', 'model_bytes', 'latency')}, indent=2))
diff --git a/scripts/csi_training/espfi_seeded.py b/scripts/csi_training/espfi_seeded.py
new file mode 100644
index 000000000..bbe53d697
--- /dev/null
+++ b/scripts/csi_training/espfi_seeded.py
@@ -0,0 +1,72 @@
+"""Lossless seed encoding for the fixed 128-dimensional CSI RFF candidate."""
+import hashlib
+import json
+from pathlib import Path
+import numpy as np
+from safetensors.numpy import load_file, save_file
+from .espfi_generalize import features
+from .espfi_kernel import predict_features
+from .espfi_train import digest, write_json
+
+SPEC = {'family': 'relative_combined', 'dimensions': 128, 'gamma_multiplier': .1,
+        'alpha': .01, 'seed': 42, 'input_features': 468}
+SHAPES = {'feature_mean': (468,), 'feature_scale': (468,), 'output_mean': (128,),
+          'weights': (128, 7), 'bias': (7,)}
+def random_map():
+    rng = np.random.default_rng(42)
+    return {'projection': rng.normal(0, np.sqrt(2*.1/468), (468, 128)),
+            'phase': rng.uniform(0, 2*np.pi, 128)}
+def tensor_hash(value):
+    return hashlib.sha256(np.ascontiguousarray(value).tobytes()).hexdigest()
+def validate(state):
+    if set(state) != set(SHAPES) or any(
+        state[k].shape != shape or state[k].dtype != np.float64 or
+        not np.isfinite(state[k]).all() for k, shape in SHAPES.items()
+    ) or not (state['feature_scale'] > 0).all():
+        raise ValueError('Invalid compact state')
+
+def export_seeded(state, output):
+    generated = random_map()
+    if set(state) != set(SHAPES) | set(generated) or any(
+        not np.array_equal(state[k], generated[k]) for k in generated
+    ):
+        raise ValueError('Projection does not match frozen seed recipe')
+    compact = {k: np.ascontiguousarray(state[k]) for k in SHAPES}
+    validate(compact)
+    root = Path(output)
+    root.mkdir(exist_ok=False, parents=True)
+    save_file(compact, str(root/'model.safetensors'))
+    report = {'status': 'complete', 'promotionAuthorized': False, 'spec': SPEC,
+              'model_sha256': digest(root/'model.safetensors'),
+              'model_bytes': (root/'model.safetensors').stat().st_size,
+              'random_map_sha256': {k: tensor_hash(v) for k,v in generated.items()},
+              'numpy_version': np.__version__, 'implementation_sha256': digest(__file__),
+              'feature_implementation_sha256': digest(Path(__file__).with_name('espfi_generalize.py')),
+              'stored_scalars': sum(v.size for v in compact.values()),
+              'runtime_scalars': sum(v.size for v in state.values()),
+              'scope': 'Lossless on-disk encoding only; projection regenerated at load, runtime memory unchanged'}
+    write_json(root/'metadata.json', report)
+    return report
+
+class SeededKernelBundle:
+    def __init__(self, directory):
+        root = Path(directory)
+        for name in ('metadata.json', 'model.safetensors'):
+            p = root/name
+            if p.is_symlink() or not p.is_file() or p.stat().st_size > 65536:
+                raise ValueError('Invalid bounded compact artifact')
+        report = json.loads((root/'metadata.json').read_text())
+        if report.get('status') != 'complete' or report.get('promotionAuthorized') is not False or report.get('spec') != SPEC:
+            raise ValueError('Invalid compact contract')
+        if digest(root/'model.safetensors') != report.get('model_sha256'):
+            raise ValueError('Compact model hash mismatch')
+        state = load_file(str(root/'model.safetensors'))
+        validate(state)
+        generated = random_map()
+        if {k:tensor_hash(v) for k,v in generated.items()} != report.get('random_map_sha256'):
+            raise ValueError('Runtime random generator differs from export')
+        state.update(generated)
+        self.state = state
+
+    def predict(self, amplitudes):
+        return predict_features(self.state, features(amplitudes, SPEC['family']))
diff --git a/scripts/improve-espfi-blend.py b/scripts/improve-espfi-blend.py
new file mode 100644
index 000000000..7e83d2268
--- /dev/null
+++ b/scripts/improve-espfi-blend.py
@@ -0,0 +1,8 @@
+#!/usr/bin/env python3
+"""Run the frozen five-weight development blend with bounded CPU threads."""
+import os
+for name in ('OPENBLAS_NUM_THREADS', 'OMP_NUM_THREADS', 'MKL_NUM_THREADS'):
+    os.environ[name] = '1'
+from csi_training.espfi_blend import main
+if __name__ == '__main__':
+    main()
diff --git a/scripts/tests/test_espfi_blend.py b/scripts/tests/test_espfi_blend.py
new file mode 100644
index 000000000..a1380feec
--- /dev/null
+++ b/scripts/tests/test_espfi_blend.py
@@ -0,0 +1,43 @@
+"""Synthetic integrity checks, not sensing accuracy evidence."""
+import copy
+import json
+from pathlib import Path
+import sys
+import tempfile
+import unittest
+import numpy as np
+sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+from csi_training.espfi_blend import run, infer, select_weight
+from test_espfi_generalize import fixture
+
+class BlendTests(unittest.TestCase):
+    def test_tie_retains_spectral_endpoint(self):
+        y = np.arange(7)
+        logits = np.eye(7)
+        selected, results = select_weight([(logits, logits)], [y])
+        self.assertEqual(selected['weight'], 0.)
+        self.assertEqual(len(results), 5)
+
+    def test_unused_endpoint_is_not_executed(self):
+        from unittest.mock import patch
+        logits = np.ones((1, 7))
+        with patch('csi_training.espfi_blend.features', return_value=np.ones((1, 468))), patch('csi_training.espfi_blend.predict_features', return_value=logits) as predict:
+            np.testing.assert_array_equal(infer([{}, None], 0., None), logits)
+            predict.assert_called_once_with({}, unittest.mock.ANY)
+
+    def test_development_cannot_change_selection_or_model(self):
+        parts, provenance = fixture()
+        with tempfile.TemporaryDirectory() as tmp:
+            root = Path(tmp)
+            first = run(parts, provenance, root/'first')
+            changed = copy.deepcopy(parts)
+            changed['validation']['x'] *= 1.25
+            changed['validation']['y'] = (changed['validation']['y'] + 1) % 7
+            second = run(changed, provenance, root/'second')
+            self.assertEqual(first['selected'], second['selected'])
+            self.assertEqual(first['model_sha256'], second['model_sha256'])
+            self.assertTrue(first['reload_exact'])
+            self.assertFalse(first['promotionAuthorized'])
+            self.assertEqual(json.loads((root/'first/status.json').read_text())['status'], 'complete')
+            with self.assertRaisesRegex(ValueError, 'Development partitions'):
+                run(dict(parts, test=parts['validation']), provenance, root/'invalid')
diff --git a/scripts/tests/test_espfi_seeded.py b/scripts/tests/test_espfi_seeded.py
new file mode 100644
index 000000000..ef14bca5b
--- /dev/null
+++ b/scripts/tests/test_espfi_seeded.py
@@ -0,0 +1,36 @@
+"""Lossless seeded-map integrity tests."""
+from pathlib import Path
+import sys
+import tempfile
+import unittest
+import numpy as np
+sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+from csi_training.espfi_kernel import fit, predict_features
+from csi_training.espfi_generalize import features
+from csi_training.espfi_seeded import SPEC, export_seeded, SeededKernelBundle
+
+class SeededTests(unittest.TestCase):
+    def test_exact_export_and_tamper_rejection(self):
+        amplitudes = np.exp(np.random.default_rng(2).normal(size=(14,52,190)))
+        x = features(amplitudes, SPEC['family'])
+        state = fit(x, np.arange(14)%7, dict(SPEC, kind='rff'))
+        with tempfile.TemporaryDirectory() as tmp:
+            path = Path(tmp)/'model'
+            report = export_seeded(state, path)
+            loaded = SeededKernelBundle(path)
+            np.testing.assert_array_equal(predict_features(state,x), loaded.predict(amplitudes))
+            self.assertLess(report['model_bytes'], 17000)
+            self.assertEqual(report['stored_scalars'], 1967)
+            self.assertEqual(report['runtime_scalars'], 61999)
+            with (path/'model.safetensors').open('ab') as f:
+                f.write(b'bad')
+            with self.assertRaisesRegex(ValueError,'hash mismatch'):
+                SeededKernelBundle(path)
+
+    def test_wrong_projection_rejected(self):
+        x = np.random.default_rng(1).normal(size=(14,468))
+        state = fit(x,np.arange(14)%7,dict(SPEC,kind='rff'))
+        state['projection'][0,0] += .1
+        with tempfile.TemporaryDirectory() as tmp:
+            with self.assertRaisesRegex(ValueError,'seed recipe'):
+                export_seeded(state,Path(tmp)/'model')