diff --git a/research/selected-replay-tooling-receipt/README.md b/research/selected-replay-tooling-receipt/README.md
new file mode 100644
index 0000000000..3196b7899f
--- /dev/null
+++ b/research/selected-replay-tooling-receipt/README.md
@@ -0,0 +1,137 @@
+# Overlap receipt: open selected-replay tooling PRs
+
+**Consolidation receipt. No new κ, no disposition, nothing closed.** The selected
+frontier and every pinned file are unchanged.
+
+This receipt covers eight open PRs at exact heads, against main `1f7a9349`. Seven
+have the selected #1094 cold replay path as their premise; that path runs
+`verify_frontier1094.py` → `1042` → `799` → `741`. The eighth, #1108, is included
+because #1142 re-adds its package. Four of them (#1101, #1108, #1142, #1151) are
+in the maintainer queue's next batch
+(`research/community-efficient200-audit/QUEUE-CURSOR.json`).
+
+| PR | Head | Author | Subject | Applies to main | Own checks at trial merge |
+|---|---|---|---|---|---|
+| #1101 | `4d45bef9` | rcfc-jreed | concurrent bit589/complex741 driver for the #741 ancestry | clean | PASS (8 tests) |
+| #1108 | `b76bb285` | martinxxx9 | compact-boundary cancellation obstruction | clean | PASS |
+| #1142 | `0c2873e6` | martinxxx9 | #1042 replay-capsule closure audit | clean | **FAIL** (see below) |
+| #1151 | `99d4f42f` | thakrarsagar | parallel layer-end controls, frontier1042 chain | clean | PASS (`verify.py`, 155 s) |
+| #1277 | `02d27951` | thakrarsagar | #1094 reuse-mode ancestry binding audit | clean | PASS |
+| #1361 | `40965b22` | thakrarsagar | CI drift/trigger guard for the 35 hash-asserted files | clean | PASS (35 pins, 0 drift, 21 tests) |
+| #1509 | `362d2f91` | thakrarsagar | checked `cpp_int` stand-in for bit589 step 4 | clean | PASS |
+| #1646 | `3f21415b` | JosieElliston | sparse phase recipes, frontier1042 `phases` steps | clean (head on `858771bc`) | not rerun |
+
+**Retention.** None of the eight heads has content already on main: no changed
+path has an identical blob at the base. The only path that exists on main is
+`.github/workflows/frontier1094.yml`, which #1361 edits. So there is nothing to
+receipt as "already integrated". Each PR needs its own review.
+
+**#1142 does not pass on current main.**
+
+1. `research/frontier1042-capsule-closure-seed75/verify.py` prints `FAIL: repository pin
+   differs: certificates/selected-result.json`. `PINS.json` pins the #1042 record
+   (sha256 `207d1f49…`) at the path that now holds #1094's record.
+2. That record is retained byte for byte at `certificates/checkpoints/frontier1042.json`.
+   Changing only `selected_record.path` to that file gives
+   `PASS_FRONTIER1042_CAPSULE_CLOSURE`. This was tested in scratch and is not part of this
+   package. The contributor or reviewer should decide whether to repin.
+3. The body's reproduce command, `make frontier1042-capsule-closure-verify`, exists
+   neither in the PR nor on main.
+4. #1142 also adds all seven files of #1108's `research/compact-boundary-cancellation-seed51/`.
+   Five of them still differ after CRLF→LF normalization. #1142's copy is the
+   earlier one: it pins `certificates/selected-result.json` to the #942 blob `3d7529d7`
+   and fails with `Source drift`. #1108's copy pins `certificates/checkpoints/frontier942.json`
+   and passes. Merging either PR and then the other gives an add/add conflict.
+
+**Premises that still hold at the base.**
+- #1277: `verify_frontier1094.py` still has exactly one bare `check_selected(...)`
+  statement, so the `--baseline1042` reuse path discards its result.
+- #1361: the guard still finds 35 live pins.
+- #1101: `verify_frontier741.py` is unchanged since #1101's base.
+- #1151, #1509: their declared inputs are unchanged.
+
+**Pairwise overlap.** Apart from the #1108/#1142 collision, no two PRs in the family change the same file. The pairs that
+look similar address different steps or questions:
+- #1151 and #1646 cover the lec and phases steps of the frontier1042 chain.
+- #1101 and #1509 both concern bit589 in the #741 ancestry. #1101 runs it concurrently
+  with complex741; #1509 replaces Boost for its step 4. #1101's driver does not scrub
+  `BOOST_INCLUDE`, but I did not test the two together.
+- #1277, #1361 and #1142 cover three different parts of the selected evidence:
+  #1277 checks the reuse-mode binding, #1361 checks CI drift and triggers, and #1142
+  checks the archive bytes.
+
+All the speed-up PRs (#1101, #1151, #1646) are opt-in and unwired. The pinned drivers
+are unchanged, so none of them shortens `make frontier1094-verify` by itself. Their
+equality claims differ, as their own PR bodies state:
+- #1151: its receipts are byte-identical to the archived ones.
+- #1646: it reproduces the pinned recipe digests.
+- #1101: its output trees match the sequential driver's only after timing fields and
+  timing-dependent digests are masked.
+
+## Reproduce
+
+```sh
+python3 -B research/selected-replay-tooling-receipt/verify.py            # base-side facts + 5 controls
+for n in 1101 1108 1142 1151 1277 1361 1509 1646; do
+  git fetch origin pull/$n/head:refs/receipt/pr$n; done                 # exact heads, if still reachable
+python3 -B research/selected-replay-tooling-receipt/verify.py --heads    # recompute per-PR facts
+```
+
+The default run, which is the registered one, needs Git history containing the base.
+It checks the following at `1f7a9349`:
+- the selected and #1042-checkpoint record hashes;
+- the cold-chain calls;
+- #1277's premise;
+- the absent make target.
+
+It also checks that five mutated receipts are rejected.
+
+`--heads` recomputes, for every recorded head:
+- the changed paths;
+- the identical-on-main paths;
+- clean application to the base;
+- the #1108/#1142 byte differences, pin and add/add conflict;
+- #1142's capsule pin.
+
+It writes one temporary merge commit object, which Git garbage-collects as unreachable.
+If a contributor force-pushes, `--heads` fails rather than silently re-reading.
+
+The trial-merge check results in `RECEIPT.json` (`trial_merge_checks_recorded`) are
+recorded evidence from this session, not recomputed by `verify.py`. They come from a
+shared macOS arm64 host with Python 3.14, and Python 3.12 for the registered packages.
+
+**Not checked:** correctness of any PR's mathematics or speed claims beyond its own
+verifier, the cold `make frontier1094-verify`, Linux, and the PRs outside this family.
+
+## Open next questions
+
+1. **Should #1142 be repinned or narrowed before review?** Its audit holds once it points
+   at the retained #1042 checkpoint. The bundled seed51 copy duplicates #1108. First step:
+   the contributor drops the seed51 files and repins one path. Blocked on: the contributor
+   or a maintainer decision.
+2. **Do other next-batch PRs collide with each other?** #1142 re-adding #1108's directory
+   was found only because both were in this family.
+
+   I ran an unregistered path-collision scan of the 100 `next_batch` heads (recorded only
+   here, not checked by `verify.py`). Each pair was merged in order with true merge parents.
+   - #1129→#1157 and #1148/#1178/#1195 merge cleanly in any order tried.
+   - Besides #1108/#1142, these pairs conflict textually:
+     - #1110/#1190 (`docs/research/pr-ledger.md`);
+     - #1112/#1137 (`Makefile`);
+     - `.gitattributes` in the gauge44-ends7 family. Merging any of #1104, #1107, #1117 or
+       #1121 and then #1124 or #1130 conflicts, even though those heads are ancestors of
+       #1124 and #1130; the reason was not traced. Merging any of the seven and then #1193
+       also conflicts. #1104→#1107→#1117→#1121 merge cleanly.
+   - #1172 conflicts with each of #1107, #1117, #1121, #1124 and #1130 inside
+     `research/gauge44-ends7-t16/` (`MANIFEST.json`, `README.md`, `RESULT.json`,
+     `data/`…). These look like competing versions of one package, which needs a reviewer's
+     choice rather than a mechanical merge. I did not compare their contents.
+3. **Which opt-in speedups should be wired into the pinned cold chain?** #1101, #1151 and
+   #1646 each state their own equality evidence (see above). Wiring them needs pinned-driver
+   changes that only a maintainer can approve.
+
+## Credit
+
+Covered PRs and their authors are listed above. The maintainer queue cursor and
+efficient-review audit are by Douglas Colkitt. Prepared by Josie Elliston's donated
+session with Claude Code (Claude Opus); see [TASK.json](TASK.json). Apache-2.0.
diff --git a/research/selected-replay-tooling-receipt/RECEIPT.json b/research/selected-replay-tooling-receipt/RECEIPT.json
new file mode 100644
index 0000000000..73c8206640
--- /dev/null
+++ b/research/selected-replay-tooling-receipt/RECEIPT.json
@@ -0,0 +1,477 @@
+{
+ "schema": "selected-replay-tooling-receipt-v1",
+ "base_commit": "1f7a934975e5eacaf83511c9ac870263bf095e05",
+ "observed_at": "PR metadata 2026-10-14T05:10Z; heads and merges rechecked 2026-10-14T05:15Z",
+ "scope": "Open PRs whose premise is the selected #1094 cold replay path (1094 -> 1042 -> 799 -> 741), plus #1108 because #1142 re-adds its package. Exact heads only; not a review of correctness, not a disposition, no closures.",
+ "main_facts": {
+  "selected_record_sha256": "10b9e340fd8e354a37a0c4813c90e5de1dd42044b5f6aca4a3fc5a42b685fa32",
+  "selected_decimal": "0.001672660197076918",
+  "frontier1042_checkpoint_sha256": "207d1f49f113c585024b9d3c17eadbb8b1be17c1321e3d190aabe2f18ce1c5b7",
+  "frontier942_checkpoint_blob": "3d7529d77a5f22d8c6f64f98bd5a0e71b8eee892",
+  "cold_chain": [
+   [
+    "scripts/verify_frontier1094.py",
+    "run('baseline1042-cold', ROOT/'scripts/verify_frontier1042.py'"
+   ],
+   [
+    "scripts/verify_frontier1042.py",
+    "run('baseline799-cold', ROOT/'scripts/verify_frontier799.py'"
+   ],
+   [
+    "scripts/verify_frontier799.py",
+    "run('ancestor',[sys.executable,'-B',ROOT/'scripts/verify_frontier741.py'"
+   ]
+  ],
+  "bare_check_selected_statements": 1,
+  "absent_make_targets": [
+   "frontier1042-capsule-closure-verify"
+  ]
+ },
+ "collision": {
+  "first": 1108,
+  "second": 1142,
+  "path_prefix": "research/compact-boundary-cancellation-seed51/",
+  "paths": 7,
+  "differ_raw": [
+   "research/compact-boundary-cancellation-seed51/CLAIM.json",
+   "research/compact-boundary-cancellation-seed51/README.md",
+   "research/compact-boundary-cancellation-seed51/RESULT.json",
+   "research/compact-boundary-cancellation-seed51/SOURCES.json",
+   "research/compact-boundary-cancellation-seed51/VALIDATION.json",
+   "research/compact-boundary-cancellation-seed51/verify.py"
+  ],
+  "differ_after_crlf_normalization": [
+   "research/compact-boundary-cancellation-seed51/CLAIM.json",
+   "research/compact-boundary-cancellation-seed51/README.md",
+   "research/compact-boundary-cancellation-seed51/SOURCES.json",
+   "research/compact-boundary-cancellation-seed51/VALIDATION.json",
+   "research/compact-boundary-cancellation-seed51/verify.py"
+  ],
+  "second_pins_selected_result_blob": "3d7529d77a5f22d8c6f64f98bd5a0e71b8eee892"
+ },
+ "capsule_pin": {
+  "pins_file": "research/frontier1042-capsule-closure-seed75/PINS.json",
+  "pinned_path": "certificates/selected-result.json"
+ },
+ "prs": [
+  {
+   "number": 1101,
+   "author": "rcfc-jreed",
+   "title": "Tooling: overlap bit589 and complex741 in the #741 ancestry replay, 17% (50% with --complex-jobs 3) less wall time (no new kappa)",
+   "head": "4d45bef9bd0b52cc4989f195cd2dd4597f4a6d08",
+   "created_at": "2026-10-13T18:11:28Z",
+   "changed": [
+    [
+     "A",
+     "docs/research/frontier741-concurrent-replay.md"
+    ],
+    [
+     "A",
+     "scripts/verify_frontier741_concurrent.py"
+    ],
+    [
+     "A",
+     "tests/test_frontier741_concurrent.py"
+    ]
+   ],
+   "paths_identical_on_base": [],
+   "paths_present_on_base_with_other_bytes": [],
+   "merges_cleanly_into_base": true,
+   "trial_merge_checks_recorded": [
+    {
+     "command": "python3 -B -m unittest discover -s tests -p test_frontier741_concurrent.py",
+     "result": "PASS, 8 tests"
+    }
+   ],
+   "github_base_ref_oid": "ba82555c64e1879e4b7decce28186f208fcb8262"
+  },
+  {
+   "number": 1108,
+   "author": "martinxxx9",
+   "title": "Research: exact compact-control boundary cancellation obstruction (no new kappa)",
+   "head": "b76bb2853be4e7001508582b10913e32ad7aba9f",
+   "created_at": "2026-10-13T18:21:07Z",
+   "changed": [
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/CLAIM.json"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/README.md"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/RESULT.json"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/SOURCES.json"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/VALIDATION.json"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/test_package.py"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/verify.py"
+    ]
+   ],
+   "paths_identical_on_base": [],
+   "paths_present_on_base_with_other_bytes": [],
+   "merges_cleanly_into_base": true,
+   "trial_merge_checks_recorded": [
+    {
+     "command": "python3 -B research/compact-boundary-cancellation-seed51/verify.py",
+     "result": "PASS_COMPACT_BOUNDARY_CANCELLATION states=40800 production=1176 controls=8"
+    }
+   ],
+   "github_base_ref_oid": "ba82555c64e1879e4b7decce28186f208fcb8262"
+  },
+  {
+   "number": 1142,
+   "author": "martinxxx9",
+   "title": "Independent verification: selected PR1042 replay-capsule closure (no new κ)",
+   "head": "0c2873e6ac844b369a5962f06ef0a74ac86cf4a4",
+   "created_at": "2026-10-13T18:59:53Z",
+   "changed": [
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/CLAIM.json"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/README.md"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/RESULT.json"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/SOURCES.json"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/VALIDATION.json"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/test_package.py"
+    ],
+    [
+     "A",
+     "research/compact-boundary-cancellation-seed51/verify.py"
+    ],
+    [
+     "A",
+     "research/frontier1042-capsule-closure-seed75/CLAIM.md"
+    ],
+    [
+     "A",
+     "research/frontier1042-capsule-closure-seed75/NOTICE.md"
+    ],
+    [
+     "A",
+     "research/frontier1042-capsule-closure-seed75/PINS.json"
+    ],
+    [
+     "A",
+     "research/frontier1042-capsule-closure-seed75/PROOF.md"
+    ],
+    [
+     "A",
+     "research/frontier1042-capsule-closure-seed75/README.md"
+    ],
+    [
+     "A",
+     "research/frontier1042-capsule-closure-seed75/RESULT.json"
+    ],
+    [
+     "A",
+     "research/frontier1042-capsule-closure-seed75/test_package.py"
+    ],
+    [
+     "A",
+     "research/frontier1042-capsule-closure-seed75/verify.py"
+    ]
+   ],
+   "paths_identical_on_base": [],
+   "paths_present_on_base_with_other_bytes": [],
+   "merges_cleanly_into_base": true,
+   "trial_merge_checks_recorded": [
+    {
+     "command": "python3 -B research/frontier1042-capsule-closure-seed75/verify.py",
+     "result": "FAIL: repository pin differs: certificates/selected-result.json"
+    },
+    {
+     "command": "python3 -B -m unittest research/frontier1042-capsule-closure-seed75/test_package.py",
+     "result": "PASS, 6 tests (fixtures only)"
+    },
+    {
+     "command": "make frontier1042-capsule-closure-verify (the PR body's reproduce command)",
+     "result": "No rule to make target"
+    },
+    {
+     "command": "python3 -B research/compact-boundary-cancellation-seed51/verify.py (#1142's copy)",
+     "result": "FAIL: Source drift: certificates/selected-result.json"
+    },
+    {
+     "command": "capsule verify.py with only PINS.json selected_record.path changed to certificates/checkpoints/frontier1042.json (scratch, not committed)",
+     "result": "PASS_FRONTIER1042_CAPSULE_CLOSURE"
+    }
+   ],
+   "github_base_ref_oid": "ce7ad1b6ab09452c3478723a2e96ed5ff212dc08"
+  },
+  {
+   "number": 1151,
+   "author": "thakrarsagar",
+   "title": "Tooling: opt-in parallel layer-end controls for the frontier1042 leaver chain, byte-identical receipts, 3.1x (extends #1059, no new kappa)",
+   "head": "99d4f42f7cfe5f60d14316ef18e9455c38eaa290",
+   "created_at": "2026-10-13T19:10:51Z",
+   "changed": [
+    [
+     "A",
+     "research/frontier1042-lec-parallel/BENCHMARK-macos-arm64.json"
+    ],
+    [
+     "A",
+     "research/frontier1042-lec-parallel/CLAIM.json"
+    ],
+    [
+     "A",
+     "research/frontier1042-lec-parallel/PINS.json"
+    ],
+    [
+     "A",
+     "research/frontier1042-lec-parallel/README.md"
+    ],
+    [
+     "A",
+     "research/frontier1042-lec-parallel/audit_worker.py"
+    ],
+    [
+     "A",
+     "research/frontier1042-lec-parallel/chain_lec.py"
+    ],
+    [
+     "A",
+     "research/frontier1042-lec-parallel/lec_parallel.py"
+    ],
+    [
+     "A",
+     "research/frontier1042-lec-parallel/test_package.py"
+    ],
+    [
+     "A",
+     "research/frontier1042-lec-parallel/verify.py"
+    ]
+   ],
+   "paths_identical_on_base": [],
+   "paths_present_on_base_with_other_bytes": [],
+   "merges_cleanly_into_base": true,
+   "trial_merge_checks_recorded": [
+    {
+     "command": "python3 -B -m unittest discover -s research/frontier1042-lec-parallel -p test_package.py",
+     "result": "PASS"
+    },
+    {
+     "command": "python3 -B research/frontier1042-lec-parallel/verify.py --work NEW_DIR",
+     "result": "PASS_FRONTIER1042_LEC_PARALLEL, 154.5 s wall"
+    }
+   ],
+   "github_base_ref_oid": "ce7ad1b6ab09452c3478723a2e96ed5ff212dc08"
+  },
+  {
+   "number": 1277,
+   "author": "thakrarsagar",
+   "title": "Research audit: the selected #1094 reuse replay discards its ancestry recheck; binding certified from committed archives (no new kappa)",
+   "head": "02d279515ff1fc468ab99a19d89461f1b6391507",
+   "created_at": "2026-10-13T21:36:35Z",
+   "changed": [
+    [
+     "A",
+     "research/frontier1094-ancestry-binding-seed69/EXPECTED.json"
+    ],
+    [
+     "A",
+     "research/frontier1094-ancestry-binding-seed69/README.md"
+    ],
+    [
+     "A",
+     "research/frontier1094-ancestry-binding-seed69/SOURCES.json"
+    ],
+    [
+     "A",
+     "research/frontier1094-ancestry-binding-seed69/TASK.json"
+    ],
+    [
+     "A",
+     "research/frontier1094-ancestry-binding-seed69/VERIFY.json"
+    ],
+    [
+     "A",
+     "research/frontier1094-ancestry-binding-seed69/verify.py"
+    ]
+   ],
+   "paths_identical_on_base": [],
+   "paths_present_on_base_with_other_bytes": [],
+   "merges_cleanly_into_base": true,
+   "trial_merge_checks_recorded": [
+    {
+     "command": "python3 scripts/research_package.py --package research/frontier1094-ancestry-binding-seed69 --check-only",
+     "result": "PASS_PACKAGE_METADATA_AND_PINS"
+    },
+    {
+     "command": "python3.12 scripts/research_package.py --package research/frontier1094-ancestry-binding-seed69",
+     "result": "PASS_FRONTIER1094_ANCESTRY_BINDING_AUDIT 22575ff2..., outcome=completed"
+    }
+   ],
+   "github_base_ref_oid": "dadfea6e8a78ff6ba901705f87532a71c6f5bbb8"
+  },
+  {
+   "number": 1361,
+   "author": "thakrarsagar",
+   "title": "Tooling: fast guard for the 35 live-checkout files the selected #1094 replay hash-asserts, plus complete replay triggers (no new kappa)",
+   "head": "40965b228001a95c1f55054e5ed661fa85190813",
+   "created_at": "2026-10-13T23:24:54Z",
+   "changed": [
+    [
+     "A",
+     "scripts/check_selected_ci_inputs.py"
+    ],
+    [
+     "A",
+     "tests/test_selected_ci_inputs.py"
+    ],
+    [
+     "M",
+     ".github/workflows/frontier1094.yml"
+    ]
+   ],
+   "paths_identical_on_base": [],
+   "paths_present_on_base_with_other_bytes": [
+    ".github/workflows/frontier1094.yml"
+   ],
+   "merges_cleanly_into_base": true,
+   "trial_merge_checks_recorded": [
+    {
+     "command": "python3 -B scripts/check_selected_ci_inputs.py --require-triggers",
+     "result": "PASS_SELECTED_CI_INPUTS, live_pins 35, pin_drift 0"
+    },
+    {
+     "command": "python3 -B -m unittest discover -s tests -p test_selected_ci_inputs.py",
+     "result": "PASS, 21 tests"
+    }
+   ],
+   "github_base_ref_oid": "bce54fb3f895cbe5cd4c0eb477c3afeed100190f"
+  },
+  {
+   "number": 1509,
+   "author": "thakrarsagar",
+   "title": "Portability tooling: checked cpp_int stand-in runs the selected replay's only native step (bit589 step 4) without Boost, matching the committed Boost receipts (no new kappa)",
+   "head": "362d2f91f30b96bc2596ff431c9baf7a78503683",
+   "created_at": "2026-10-14T02:00:09Z",
+   "changed": [
+    [
+     "A",
+     "research/bit589-checked-cpp-int-seed92/EXPECTED.json"
+    ],
+    [
+     "A",
+     "research/bit589-checked-cpp-int-seed92/README.md"
+    ],
+    [
+     "A",
+     "research/bit589-checked-cpp-int-seed92/SOURCES.json"
+    ],
+    [
+     "A",
+     "research/bit589-checked-cpp-int-seed92/TASK.json"
+    ],
+    [
+     "A",
+     "research/bit589-checked-cpp-int-seed92/VERIFY.json"
+    ],
+    [
+     "A",
+     "research/bit589-checked-cpp-int-seed92/include/boost/multiprecision/cpp_int.hpp"
+    ],
+    [
+     "A",
+     "research/bit589-checked-cpp-int-seed92/mutants.py"
+    ],
+    [
+     "A",
+     "research/bit589-checked-cpp-int-seed92/verify.py"
+    ]
+   ],
+   "paths_identical_on_base": [],
+   "paths_present_on_base_with_other_bytes": [],
+   "merges_cleanly_into_base": true,
+   "trial_merge_checks_recorded": [
+    {
+     "command": "python3 scripts/research_package.py --package research/bit589-checked-cpp-int-seed92 --check-only",
+     "result": "PASS_PACKAGE_METADATA_AND_PINS"
+    },
+    {
+     "command": "python3.12 scripts/research_package.py --package research/bit589-checked-cpp-int-seed92",
+     "result": "PASS_BIT589_STEP4_CHECKED_CPP_INT_STANDIN, outcome=completed"
+    }
+   ],
+   "github_base_ref_oid": "ef5f39403610d231a0c27e8a6b4f08c10209bcd6"
+  },
+  {
+   "number": 1646,
+   "author": "JosieElliston",
+   "title": "Tooling: exact sparse phase recipes reproduce the three frontier1042 phases pins, 12x on a shared host (no new kappa)",
+   "head": "3f21415bd54bfc7028c3d92f047cac876bc95a91",
+   "created_at": "2026-10-14T05:05:15Z",
+   "changed": [
+    [
+     "A",
+     "research/frontier1042-phase-fastpath/BENCHMARK-macos-arm64.json"
+    ],
+    [
+     "A",
+     "research/frontier1042-phase-fastpath/README.md"
+    ],
+    [
+     "A",
+     "research/frontier1042-phase-fastpath/SOURCES.json"
+    ],
+    [
+     "A",
+     "research/frontier1042-phase-fastpath/TASK.json"
+    ],
+    [
+     "A",
+     "research/frontier1042-phase-fastpath/VERIFY.json"
+    ],
+    [
+     "A",
+     "research/frontier1042-phase-fastpath/bench.py"
+    ],
+    [
+     "A",
+     "research/frontier1042-phase-fastpath/verify.py"
+    ]
+   ],
+   "paths_identical_on_base": [],
+   "paths_present_on_base_with_other_bytes": [],
+   "merges_cleanly_into_base": true,
+   "trial_merge_checks_recorded": [
+    {
+     "command": "(base is this receipt's base; checked by its own session, not rerun here)",
+     "result": "not rerun"
+    }
+   ],
+   "github_base_ref_oid": "1f7a934975e5eacaf83511c9ac870263bf095e05"
+  }
+ ],
+ "trial_merge_checks_environment": "macOS arm64, shared host (load 15-30), python3 = 3.14, python3.12 for registered packages; run in a scratch worktree at the trial merge of base and head"
+}
diff --git a/research/selected-replay-tooling-receipt/SOURCES.json b/research/selected-replay-tooling-receipt/SOURCES.json
new file mode 100644
index 0000000000..029af4b180
--- /dev/null
+++ b/research/selected-replay-tooling-receipt/SOURCES.json
@@ -0,0 +1,42 @@
+{
+  "schema_version": 1,
+  "base_commit": "1f7a934975e5eacaf83511c9ac870263bf095e05",
+  "files": [
+    {
+      "path": "certificates/checkpoints/frontier1042.json",
+      "usage": "input",
+      "git_blob": "f451ced6626a1f03aba6915ce23a136b01ebe51d",
+      "sha256": "207d1f49f113c585024b9d3c17eadbb8b1be17c1321e3d190aabe2f18ce1c5b7"
+    },
+    {
+      "path": "certificates/selected-result.json",
+      "usage": "input",
+      "git_blob": "ae6a99f28aa468649eb66a361e764d769363bf11",
+      "sha256": "10b9e340fd8e354a37a0c4813c90e5de1dd42044b5f6aca4a3fc5a42b685fa32"
+    },
+    {
+      "path": "docs/research/agent-task-catalog.json",
+      "usage": "provenance",
+      "git_blob": "06c96f5579bb67ed1b86d334e78fbed7da6945f1",
+      "sha256": "6686ad58f1fbdbc87134a78901b60fd53a20d3984355e91defbbebc9e9fa8075"
+    },
+    {
+      "path": "scripts/verify_frontier1042.py",
+      "usage": "input",
+      "git_blob": "e4f129b0570865330e39ae11eafafe7167f7e374",
+      "sha256": "700fdcaeb6e8f57f6e63c71c2dd1652fc5b183e8d706cd092779bdc0d271e854"
+    },
+    {
+      "path": "scripts/verify_frontier1094.py",
+      "usage": "input",
+      "git_blob": "96e6c1386bd052b9bcaf136d934406f3f0c3f777",
+      "sha256": "c7e20f59968ed5736fb859735de4de207de3418083e37012310ebcded946b949"
+    },
+    {
+      "path": "scripts/verify_frontier799.py",
+      "usage": "input",
+      "git_blob": "c0d8b0d0c9c52ed17ad37cbf7dc88838daea203a",
+      "sha256": "19fe1b32079095160dc00fe2f7df75e0fcbc82cff37f7159b755c8a63bd5ce99"
+    }
+  ]
+}
diff --git a/research/selected-replay-tooling-receipt/TASK.json b/research/selected-replay-tooling-receipt/TASK.json
new file mode 100644
index 0000000000..6a1f0c69c7
--- /dev/null
+++ b/research/selected-replay-tooling-receipt/TASK.json
@@ -0,0 +1,72 @@
+{
+  "schema_version": 1,
+  "task_id": "overlap-receipt",
+  "priority_revision": 3,
+  "base_commit": "1f7a934975e5eacaf83511c9ac870263bf095e05",
+  "original_card": {
+    "id": "overlap-receipt",
+    "question": "What exact content and credit of a small named PR set has already been retained?",
+    "starting_points": [
+      "docs/research/pr-ledger.md",
+      "CONTRIBUTORS.md"
+    ],
+    "methods": [
+      "Compare exact heads and retained artifacts to write a source-bound disposition receipt.",
+      "Audit an existing receipt for missing content or predecessor attribution."
+    ],
+    "acceptance_gate": "Separate complete integration, partial retention and changed heads; make no autonomous closures.",
+    "first_step": {
+      "command": [
+        "python3",
+        "-B",
+        "scripts/research_baseline.py"
+      ],
+      "expected": "PASS_RESEARCH_BASELINE_BINDINGS_ONLY",
+      "inspect": "Read one small PR set in the ledger and identify exact reviewed heads and unresolved content.",
+      "scope": "Positive control / source-bound orientation only; this is not a new construction or full cold replay."
+    },
+    "first_experiment": "Compare that set to retained artifacts; produce a complete or explicitly partial disposition receipt.",
+    "bottleneck_link": "Reliable overlap evidence preserves credit and prevents repeated review of already-retained material.",
+    "allowed_variations": [
+      "One small related PR family or one existing integration receipt."
+    ],
+    "scope_change_triggers": [
+      "Treating matching titles or one shared blob as proof of full incorporation."
+    ],
+    "overlap_terms": [
+      "overlap receipt",
+      "partial integration",
+      "attribution"
+    ]
+  },
+  "scope_status": "refined",
+  "actual_scope": "Exact-head overlap and retention receipt for eight open PRs on the selected #1094 cold replay path (#1101, #1142, #1151, #1277, #1361, #1509, #1646) plus #1108, which #1142 duplicates, against main 1f7a9349.",
+  "scope_change_reason": "The card names no family; this picks the open replay-tooling family because four members are in the maintainer queue next batch and none had a family-level receipt. No ledger entry exists for these PRs yet, so the receipt compares heads with main rather than with a prior integration receipt.",
+  "bottleneck_link": "Side result for review throughput: it tells the reviewer that nothing in this family is already retained, that #1142 fails on current main and collides with #1108, and which premises still hold, so the next batch is not reviewed twice or merged into a conflict.",
+  "budget_minutes": 60,
+  "stop_rule": "Stop after one receipt for the named family; no correctness review of the PRs, no dispositions, no wider queue census.",
+  "outcome": "completed",
+  "evidence": "verify.py (default: base-side facts and five receipt-mutation controls; --heads: recomputes per-PR changed paths, retention, clean application, the #1108/#1142 collision and the #1142 capsule pin). RECEIPT.json records each PR's own checks run at the trial merge in this session.",
+  "author": "Josie Elliston (with Claude)",
+  "ai_assistance": "Prepared with Claude Code (Claude Opus) in Josie Elliston's donated session. No independent human review.",
+  "open_questions": [
+    {
+      "question": "Should #1142 be repinned to certificates/checkpoints/frontier1042.json and its bundled copy of #1108's package dropped?",
+      "why_it_matters": "As submitted it fails on current main and conflicts with #1108; the capsule audit itself passes after a one-path repin.",
+      "first_step": "Contributor or reviewer applies the one-line PINS.json path change and removes research/compact-boundary-cancellation-seed51 from #1142.",
+      "blocked_by": "Contributor or maintainer decision."
+    },
+    {
+      "question": "Do other next-batch PRs collide in ways a batch merge will hit?",
+      "why_it_matters": "The #1108/#1142 add/add collision was found only because both fell in this family.",
+      "first_step": "Done once in scratch (README, open question 2): besides #1108/#1142, textual conflicts #1110/#1190 (pr-ledger.md), #1112/#1137 (Makefile), .gitattributes between #1104/#1107/#1117/#1121 and #1124/#1130 and between the gauge44-ends7 heads and #1193, and competing research/gauge44-ends7-t16 contents between #1172 and #1107/#1117/#1121/#1124/#1130. Repeat when the cursor moves.",
+      "blocked_by": "Nothing."
+    },
+    {
+      "question": "Which opt-in replay speedups (#1101, #1151, #1646) should be wired into the pinned cold chain?",
+      "why_it_matters": "Each states its own equality evidence (#1151 byte-identical receipts, #1646 pinned digests, #1101 equal after masking timing fields), but none shortens make frontier1094-verify until the pinned drivers call it.",
+      "first_step": "Maintainer chooses whether to change verify_frontier741/799 and reproduce_leaver_chain.py pins.",
+      "blocked_by": "Pinned-driver changes need maintainer approval."
+    }
+  ]
+}
diff --git a/research/selected-replay-tooling-receipt/VERIFY.json b/research/selected-replay-tooling-receipt/VERIFY.json
new file mode 100644
index 0000000000..833b004f57
--- /dev/null
+++ b/research/selected-replay-tooling-receipt/VERIFY.json
@@ -0,0 +1,24 @@
+{
+  "schema_version": 1,
+  "status": "ready",
+  "python": "3.12",
+  "requirements": [],
+  "inputs": [
+    "certificates/checkpoints/frontier1042.json",
+    "certificates/selected-result.json",
+    "scripts/verify_frontier1042.py",
+    "scripts/verify_frontier1094.py",
+    "scripts/verify_frontier799.py"
+  ],
+  "commands": [
+    {
+      "argv": [
+        "{python}",
+        "-B",
+        "{package}/verify.py"
+      ],
+      "timeout_seconds": 60,
+      "checks": "Base-side facts at 1f7a9349 (selected and #1042 checkpoint hashes, cold chain, #1277 premise, absent make target) and five receipt-mutation controls. Per-PR head facts need --heads and fetched PR refs, so they are not part of the registered run."
+    }
+  ]
+}
diff --git a/research/selected-replay-tooling-receipt/verify.py b/research/selected-replay-tooling-receipt/verify.py
new file mode 100644
index 0000000000..f393ce25b2
--- /dev/null
+++ b/research/selected-replay-tooling-receipt/verify.py
@@ -0,0 +1,211 @@
+#!/usr/bin/env python3
+"""Check the selected-replay tooling overlap receipt (stdlib only).
+
+Default mode checks the main-side facts at the receipt's base commit. With
+--heads it also recomputes every per-PR fact from the exact PR head objects,
+which must already be in the local object store (see README for the fetch).
+
+Josie Elliston's donated session with Claude Code. Apache-2.0.
+"""
+import argparse
+import ast
+import hashlib
+import json
+import subprocess
+import sys
+from pathlib import Path
+
+PKG = Path(__file__).resolve().parent
+ROOT = PKG.parents[1]
+
+
+def fail(msg):
+    print('FAIL_SELECTED_REPLAY_TOOLING_RECEIPT:', msg)
+    sys.exit(1)
+
+
+def require(cond, msg):
+    if not cond:
+        fail(msg)
+
+
+def git(*args, check=True):
+    r = subprocess.run(['git', '-C', str(ROOT), *args], capture_output=True)
+    if check and r.returncode:
+        fail('git %s: %s' % (' '.join(args), r.stderr.decode(errors='replace').strip()))
+    return r
+
+
+def show(rev, path):
+    return git('show', '%s:%s' % (rev, path)).stdout
+
+
+def has_object(rev):
+    return git('cat-file', '-e', rev + '^{commit}', check=False).returncode == 0
+
+
+def blob(rev, path):
+    r = git('rev-parse', '--verify', '-q', '%s:%s' % (rev, path), check=False)
+    return r.stdout.decode().strip() if r.returncode == 0 else None
+
+
+def sha256(data):
+    return hashlib.sha256(data).hexdigest()
+
+
+def main_side(rc):
+    base = rc['base_commit']
+    m = rc['main_facts']
+    # Selected record moved to #1094; the #1042 record is retained as a checkpoint.
+    sel = show(base, 'certificates/selected-result.json')
+    ck = show(base, 'certificates/checkpoints/frontier1042.json')
+    require(sha256(sel) == m['selected_record_sha256'], 'selected record differs at base')
+    require(json.loads(sel)['decimal'] == m['selected_decimal'], 'selected decimal differs')
+    require(sha256(ck) == m['frontier1042_checkpoint_sha256'], 'frontier1042 checkpoint differs')
+    require(sha256(sel) != sha256(ck), 'selected record still equals the #1042 record')
+    require(blob(base, 'certificates/checkpoints/frontier942.json') == m['frontier942_checkpoint_blob'],
+            'frontier942 checkpoint blob differs')
+    # Live files must equal the base for the default (registered) run.
+    for p in ('certificates/selected-result.json', 'certificates/checkpoints/frontier1042.json'):
+        require(sha256((ROOT / p).read_bytes()) == sha256(show(base, p)), 'live %s drifted from base' % p)
+    # Cold chain 1094 -> 1042 -> 799 -> 741.
+    for script, callee in m['cold_chain']:
+        require(callee.encode() in show(base, script), '%s no longer runs %s' % (script, callee))
+    # PR1277 premise: the --baseline1042 reuse path discards check_selected's result.
+    # Every call of check_selected must be a bare statement on `ancestor`, i.e. its result unused.
+    tree = ast.parse(show(base, 'scripts/verify_frontier1094.py'))
+    calls = [n for n in ast.walk(tree) if isinstance(n, ast.Call)
+             and getattr(n.func, 'id', None) == 'check_selected']
+    bare = [n.value for n in ast.walk(tree) if isinstance(n, ast.Expr) and n.value in calls
+            and getattr(n.value.args[0], 'id', None) == 'ancestor']
+    require(len(calls) == len(bare) == m['bare_check_selected_statements'],
+            'check_selected calls %d, bare on ancestor %d' % (len(calls), len(bare)))
+    # PR1142's documented make target does not exist at base.
+    mk = show(base, 'Makefile').decode()
+    for tgt in m['absent_make_targets']:
+        require(('\n%s:' % tgt) not in mk, 'make target %s now exists' % tgt)
+    return ['base %s: selected %s, #1042 checkpoint retained, cold chain, PR1277 premise, '
+            '%d absent make target(s)' % (base[:8], m['selected_decimal'], len(m['absent_make_targets']))]
+
+
+def merge_tree(a, b):
+    r = git('merge-tree', '--write-tree', '--name-only', a, b, check=False)
+    lines = r.stdout.decode().splitlines()
+    return r.returncode, lines[0] if lines else None, lines
+
+
+def pr_facts(base, pr):
+    head = pr['head']
+    mb = git('merge-base', base, head).stdout.decode().strip()
+    diff = git('diff', '--name-status', '--no-renames', mb, head).stdout.decode().splitlines()
+    changed = sorted(tuple(x.split('\t', 1)) for x in diff)
+    on_main_same = sorted(p for _, p in changed if blob(base, p) is not None and blob(base, p) == blob(head, p))
+    on_main_diff = sorted(p for _, p in changed if blob(base, p) is not None and blob(base, p) != blob(head, p))
+    code, _, _ = merge_tree(base, head)
+    return {
+        'changed': [list(c) for c in changed],
+        'paths_identical_on_base': on_main_same,
+        'paths_present_on_base_with_other_bytes': on_main_diff,
+        'merges_cleanly_into_base': code == 0,
+    }
+
+
+def unexpected_shared(rc):
+    c = rc['collision']
+    owners = {}
+    for pr in rc['prs']:
+        for _, path in pr['changed']:
+            owners.setdefault(path, []).append(pr['number'])
+    return sorted(k for k, v in owners.items() if len(v) > 1
+                  and not (k.startswith(c['path_prefix']) and v == [c['first'], c['second']]))
+
+
+def heads(rc):
+    base = rc['base_commit']
+    missing = [str(p['number']) for p in rc['prs'] if not has_object(p['head'])]
+    require(not missing, 'missing PR head objects for %s; fetch them as in README' % ', '.join(missing))
+    out = []
+    for pr in rc['prs']:
+        got = pr_facts(base, pr)
+        for k, v in got.items():
+            require(pr[k] == v, 'PR%d %s: receipt %r, recomputed %r' % (pr['number'], k, pr[k], v))
+        out.append('PR%d %s: %d paths, clean=%s, retained=%d'
+                   % (pr['number'], pr['head'][:8], len(got['changed']),
+                      got['merges_cleanly_into_base'], len(got['paths_identical_on_base'])))
+    c = rc['collision']
+    a, b = (next(p for p in rc['prs'] if p['number'] == n) for n in (c['first'], c['second']))
+    # Both PRs add the same package directory with different bytes.
+    # Apart from the recorded collision, no two family PRs change the same path.
+    require(not unexpected_shared(rc), 'unexpected shared paths %r' % unexpected_shared(rc))
+    bad = json.loads(json.dumps(rc))
+    bad['prs'][0]['changed'].append(['A', bad['prs'][1]['changed'][0][1]])
+    require(unexpected_shared(bad), 'control: injected shared path was accepted')
+    pa = {p for _, p in map(tuple, a['changed']) if p.startswith(c['path_prefix'])}
+    pb = {p for _, p in map(tuple, b['changed']) if p.startswith(c['path_prefix'])}
+    require(pa == pb and len(pa) == c['paths'], 'collision path set differs')
+    raw = sorted(p for p in pa if blob(a['head'], p) != blob(b['head'], p))
+    lf = sorted(p for p in pa if show(a['head'], p).replace(b'\r\n', b'\n') != show(b['head'], p).replace(b'\r\n', b'\n'))
+    require(raw == c['differ_raw'] and lf == c['differ_after_crlf_normalization'], 'collision bytes differ: %r %r' % (raw, lf))
+    # The copy in the second PR pins selected-result.json to the #942 record blob.
+    src = json.loads(show(b['head'], c['path_prefix'] + 'SOURCES.json').replace(b'\r\n', b'\n'))
+    files = src.get('files', src)
+    pinned = files['certificates/selected-result.json']['git_blob']
+    require(pinned == c['second_pins_selected_result_blob'] == rc['main_facts']['frontier942_checkpoint_blob'],
+            'second copy pin %s' % pinned)
+    require(blob(base, 'certificates/selected-result.json') != pinned, 'base selected record equals #942 blob')
+    # Merging the first then the second conflicts (add/add).
+    t = git('merge-tree', '--write-tree', base, a['head']).stdout.decode().split()[0]
+    mc = git('commit-tree', t, '-p', base, '-p', a['head'], '-m', 'receipt trial merge').stdout.decode().strip()
+    code, _, lines = merge_tree(mc, b['head'])
+    require(code == 1 and any('CONFLICT (add/add)' in x for x in lines), 'sequential merge did not conflict')
+    # PR1142's capsule audit pins the #1042 record at the path that is now #1094's.
+    p = rc['capsule_pin']
+    pins = json.loads(show(b['head'], p['pins_file']))
+    require(pins['selected_record']['path'] == p['pinned_path'], 'capsule pin path')
+    require(pins['selected_record']['sha256'] == rc['main_facts']['frontier1042_checkpoint_sha256'], 'capsule pin sha')
+    out.append('collision PR%d/PR%d: %d paths, %d differ raw, %d after CRLF normalization; '
+               'sequential merge add/add conflict' % (c['first'], c['second'], len(pa), len(raw), len(lf)))
+    return out
+
+
+def controls(rc):
+    """Each mutated receipt must be rejected by the base-side checks."""
+    import copy
+    import contextlib
+    import io
+    muts = {
+        'selected decimal': ('selected_decimal', '0.001672188119205421'),
+        'checkpoint sha': ('frontier1042_checkpoint_sha256', '0' * 64),
+        'chain callee': ('cold_chain', [['scripts/verify_frontier1094.py', 'scripts/verify_frontier890.py']]),
+        'PR1277 premise': ('bare_check_selected_statements', 0),
+        'existing target': ('absent_make_targets', ['frontier1094-verify']),
+    }
+    for name, (key, value) in muts.items():
+        bad = copy.deepcopy(rc)
+        bad['main_facts'][key] = value
+        try:
+            with contextlib.redirect_stdout(io.StringIO()):
+                main_side(bad)
+        except SystemExit:
+            continue
+        fail('control %r was accepted' % name)
+    return ['%d receipt mutation controls rejected' % len(muts)]
+
+
+def main():
+    ap = argparse.ArgumentParser()
+    ap.add_argument('--heads', action='store_true', help='also recompute per-PR facts from fetched heads')
+    a = ap.parse_args()
+    if sys.flags.optimize:
+        fail('run without -O')
+    rc = json.loads((PKG / 'RECEIPT.json').read_text())
+    lines = main_side(rc) + controls(rc)
+    if a.heads:
+        lines += heads(rc)
+    for line in lines:
+        print(line)
+    print('PASS_SELECTED_REPLAY_TOOLING_RECEIPT', 'heads' if a.heads else 'base-only')
+
+
+if __name__ == '__main__':
+    main()