Name the checkpoint behind the #1042 status link

research/historical-1042-link/README.md

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+# The #1042 status link opens the live selected record
+
+**Partial. No new exponent.**
+
+The historical section "Historical status through #1042" prints
+
+```text
+0.001672188119205421
+```
+
+and links "Selected record" to `certificates/selected-result.json`. That file's
+kappa is `836330098538459/500000000000000000`. The same href is the live
+section's selected-record link.
+
+The printed decimal equals the checkpoint
+
+```text
+certificates/checkpoints/frontier1042.json
+```
+
+whose kappa is `1672188119205421/1000000000000000000`. The live record names
+that file as `previous_record`. The historical wording is left as printed.
+
+## What was executed
+
+The checker reads the status page, the live record and the checkpoint. It
+does not rewrite the page.
+
+## Scope and evidence
+
+Original card: `scope-navigation`, priority revision 6, refined to this link.
+[TASK.json](TASK.json) records the scope change. [RESULT.json](RESULT.json)
+is the executed receipt and is not rewritten. [SOURCES.json](SOURCES.json)
+pins the three files. No selected frontier file changes.
+
+Upstream checkpoint: `20ecf2891d80b5acf18d980b2164fb44ea7faa90`, priority
+revision 6, checked 2026-10-18 05:57 UTC. Catalogue and selected record match
+that commit. Handoff discussion #1166, through the PR3560 note at 2026-10-18
+05:54 UTC, was released work. Draw seed `1c96b80206e3f5d545684875a27e1d7c`,
+track `consolidation`, first card `scope-navigation`.
+
+## Reproduce
+
+From the repository root, standard-library Python 3.12:
+
+```sh
+python3.12 -B research/historical-1042-link/verify.py
+python3.12 -B research/historical-1042-link/test_verify.py
+python3.12 -B scripts/research_package.py --package research/historical-1042-link
+```
+
+The check finishes in under a second.
+
+## Open next questions
+
+The #1042 section's Selected record link opens the live record. The printed
+decimal is the frontier1042 checkpoint.
+
+## Credit
+
+The status page and both records are the repository's. The live kappa is
+Rohan Arun's #1094 selection. The checkpoint kappa is the #1042 record named
+by that selection's `previous_record` field.
+
+Prepared by jwr with substantial Cursor agent assistance. No independent human
+review is claimed. Apache-2.0.

research/historical-1042-link/RESULT.json

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+{
+  "historical_href": "../../certificates/selected-result.json",
+  "checkpoint": "certificates/checkpoints/frontier1042.json",
+  "historical_kappa": "1672188119205421/1000000000000000000",
+  "live_kappa": "836330098538459/500000000000000000",
+  "same_href": true,
+  "kappas_differ": true,
+  "no_new_kappa": true
+}

research/historical-1042-link/SOURCES.json

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+{
+  "schema_version": 1,
+  "base_commit": "20ecf2891d80b5acf18d980b2164fb44ea7faa90",
+  "files": [
+    {
+      "path": "docs/research/agent-task-catalog.json",
+      "usage": "provenance",
+      "git_blob": "67f085acd86acd7d4e03922d9cf4b26bca66fed5",
+      "sha256": "47b42433f5a85809a3aadd29c2c339da2c6ed728e4f7762df6b88bccb7874cf0"
+    },
+    {
+      "path": "docs/research/current-status.md",
+      "usage": "input",
+      "git_blob": "4e0a8b7cdacc1d9680f7f81d03624118bb20416d",
+      "sha256": "00a08925c51b26d168b8099ddeed659ac4381f7e04f3c7fd0e9de8e71f206823"
+    },
+    {
+      "path": "certificates/selected-result.json",
+      "usage": "input",
+      "git_blob": "b1fea0c94436b236cc2b7d41a7be032811b94c81",
+      "sha256": "bb2eaa58647b353f88d0aec2eafb9d30df1be53589231b23e12ceef3e4bad129"
+    },
+    {
+      "path": "certificates/checkpoints/frontier1042.json",
+      "usage": "input",
+      "git_blob": "f451ced6626a1f03aba6915ce23a136b01ebe51d",
+      "sha256": "207d1f49f113c585024b9d3c17eadbb8b1be17c1321e3d190aabe2f18ce1c5b7"
+    }
+  ]
+}

research/historical-1042-link/TASK.json

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+{
+  "schema_version": 1,
+  "task_id": "scope-navigation",
+  "priority_revision": 6,
+  "base_commit": "20ecf2891d80b5acf18d980b2164fb44ea7faa90",
+  "original_card": {
+    "id": "scope-navigation",
+    "question": "Can one misleading historical-current claim or missing research cross-reference be corrected?",
+    "starting_points": [
+      "docs/research/current-status.md",
+      "docs/research/pr-ledger.md",
+      "certificates/selected-result.json"
+    ],
+    "methods": [
+      "Trace one confusing path from onboarding to its authoritative source.",
+      "Index one tightly related family of obstructions with explicit excluded and open hypotheses."
+    ],
+    "acceptance_gate": "Produce evidence-backed navigation, preserve historical records and avoid a duplicate global survey.",
+    "first_step": {
+      "command": [
+        "python3",
+        "-B",
+        "scripts/research_baseline.py"
+      ],
+      "expected": "PASS_RESEARCH_BASELINE_BINDINGS_ONLY",
+      "inspect": "Follow one link from the selected record to its review and compare a potentially stale historical claim.",
+      "scope": "Positive control / source-bound orientation only; this is not a new construction or full cold replay."
+    },
+    "first_experiment": "Repair one confusing path or produce a scoped map of one related obstruction family.",
+    "bottleneck_link": "Clear navigation lowers entry cost for central research; a global survey without a concrete fix is not required.",
+    "allowed_variations": [
+      "One historical-current ambiguity or one bounded family index."
+    ],
+    "scope_change_triggers": [
+      "Rewriting frozen scientific packages just to change their historical wording."
+    ],
+    "overlap_terms": [
+      "current status",
+      "historical checkpoint",
+      "scope navigation"
+    ]
+  },
+  "scope_status": "refined",
+  "actual_scope": "Trace the Selected record link in the #1042 historical section to the live record, and name the checkpoint that carries the printed kappa.",
+  "scope_change_reason": "The status page already labels later sections as historical. This package follows one link inside the #1042 section. It does not edit that page.",
+  "bottleneck_link": "The link target's kappa is the live #1094 value. The printed #1042 decimal is the frontier1042 checkpoint. The selected kappa is unchanged.",
+  "budget_minutes": 60,
+  "stop_rule": "Trace this one link. Do not survey the other historical sections and do not rewrite the status page.",
+  "outcome": "partial",
+  "evidence": "The #1042 section links to certificates/selected-result.json and prints 0.001672188119205421. That decimal is the frontier1042 checkpoint. The live kappa differs.",
+  "author": "jwr",
+  "ai_assistance": "Substantial assistance from the Cursor coding agent in the execution, checker and writeup.",
+  "open_questions": [],
+  "no_open_questions_reason": "The #1042 section's Selected record link is this one path. The matching checkpoint is frontier1042.json. Surveying later historical sections would leave this link."
+}

research/historical-1042-link/VERIFY.json

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+{
+  "schema_version": 1,
+  "status": "ready",
+  "python": "3.12",
+  "requirements": [],
+  "inputs": [
+    "docs/research/current-status.md",
+    "certificates/selected-result.json",
+    "certificates/checkpoints/frontier1042.json"
+  ],
+  "commands": [
+    {
+      "argv": ["{python}", "-B", "{package}/verify.py"],
+      "timeout_seconds": 30,
+      "checks": "Compare the #1042 status link with the live record and the frontier1042 checkpoint."
+    },
+    {
+      "argv": ["{python}", "-B", "{package}/test_verify.py"],
+      "timeout_seconds": 30,
+      "checks": "Check the printed decimal and the historical section cut."
+    }
+  ]
+}

research/historical-1042-link/test_verify.py

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+#!/usr/bin/env python3
+"""The printed #1042 decimal is the checkpoint fraction, not the live one."""
+
+import importlib.util
+from fractions import Fraction
+from pathlib import Path
+
+HERE = Path(__file__).resolve().parent
+spec = importlib.util.spec_from_file_location("historical_1042_link", HERE / "verify.py")
+verify = importlib.util.module_from_spec(spec)
+spec.loader.exec_module(verify)
+
+
+def main():
+    if Fraction(verify.SHOWN) != Fraction("1672188119205421/1000000000000000000"):
+        raise SystemExit("the printed decimal moved")
+    section = verify.historical_section(
+        "live\n# Historical status through #1042\nbody\n# Historical status through #942\n"
+    )
+    if section != "# Historical status through #1042\nbody\n":
+        raise SystemExit("the section cut moved")
+    print("PASS_HISTORICAL_1042_LINK_TESTS groups=1")
+
+
+if __name__ == "__main__":
+    main()

research/historical-1042-link/verify.py

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+#!/usr/bin/env python3
+"""Separate the #1042 status link from the live selected record.
+
+The historical section states the #1042 kappa and links to the live record.
+The matching checkpoint is the selected record's previous_record field.
+"""
+
+import hashlib
+import json
+from fractions import Fraction
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[2]
+PACKAGE = Path(__file__).resolve().parent
+STATUS = ROOT / "docs/research/current-status.md"
+MARKER = "PASS_HISTORICAL_1042_LINK kappas_differ=true no_new_kappa"
+HREF = "../../certificates/selected-result.json"
+CHECKPOINT = "certificates/checkpoints/frontier1042.json"
+SHOWN = "0.001672188119205421"
+
+
+def fail(message):
+    raise SystemExit("FAIL_HISTORICAL_1042_LINK " + message)
+
+
+def require(condition, message):
+    if not condition:
+        fail(message)
+
+
+def sha256(path):
+    digest = hashlib.sha256()
+    with path.open("rb") as handle:
+        for block in iter(lambda: handle.read(1 << 20), b""):
+            digest.update(block)
+    return digest.hexdigest()
+
+
+def authenticate():
+    sources = json.loads((PACKAGE / "SOURCES.json").read_text(encoding="utf-8"))
+    pinned = {row["path"]: row for row in sources["files"] if row["usage"] == "input"}
+    expected = {
+        "docs/research/current-status.md",
+        "certificates/selected-result.json",
+        "certificates/checkpoints/frontier1042.json",
+    }
+    require(set(pinned) == expected, "input inventory changed")
+    for path, row in pinned.items():
+        require(sha256(ROOT / path) == row["sha256"], "input drift " + path)
+
+
+def historical_section(text):
+    start = text.index("# Historical status through #1042")
+    end = text.index("# Historical status through #942")
+    return text[start:end]
+
+
+def evaluate():
+    authenticate()
+    text = STATUS.read_text(encoding="utf-8")
+    section = historical_section(text)
+    live = json.loads((ROOT / "certificates/selected-result.json").read_text(encoding="utf-8"))
+    old = json.loads((ROOT / CHECKPOINT).read_text(encoding="utf-8"))
+    require(HREF in section, "the historical section lost the live-record link")
+    require(SHOWN in section, "the historical kappa sentence moved")
+    require(Fraction(SHOWN) == Fraction(old["kappa"]), "the checkpoint kappa left the printed decimal")
+    require(live["previous_record"] == CHECKPOINT, "the previous-record pointer moved")
+    require(Fraction(live["kappa"]) != Fraction(old["kappa"]), "the live and historical kappas agree")
+    require(text.index(HREF) < text.index("# Historical status through #1042"), "the live section lost its record link")
+    return {
+        "historical_href": HREF,
+        "checkpoint": CHECKPOINT,
+        "historical_kappa": old["kappa"],
+        "live_kappa": live["kappa"],
+        "same_href": True,
+        "kappas_differ": True,
+        "no_new_kappa": True,
+    }
+
+
+def main():
+    observed = evaluate()
+    stored = json.loads((PACKAGE / "RESULT.json").read_text(encoding="utf-8"))
+    require(observed == stored, "RESULT.json does not match the execution: " + json.dumps(observed, sort_keys=True))
+    print(MARKER)
+
+
+if __name__ == "__main__":
+    main()