feat: gate author work on early duplicate-work detection (Closes #400)

Add author_duplicate_work_gate and enforce it at claim, lock, and PR
creation. Expose gitea_assess_author_duplicate_work for pre-commit/push
checks and extend work-issue final-report verification.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

author_duplicate_work_gate.py

@@ -0,0 +1,198 @@
+"""Early duplicate-work detection for author work-issue flows (#400)."""
+
+from __future__ import annotations
+
+import re
+from typing import Any
+
+from issue_claim_heartbeat import (
+    _linked_open_pr,
+    _matching_branch_names,
+    classify_issue_claim,
+)
+
+STAGES = (
+    "claim",
+    "lock",
+    "worktree",
+    "edit",
+    "commit",
+    "push",
+    "create_pr",
+)
+
+ELIGIBILITY_OPEN_PR_EXISTS = "OPEN_PR_EXISTS"
+ELIGIBILITY_DUPLICATE_BRANCH_EXISTS = "DUPLICATE_BRANCH_EXISTS"
+ELIGIBILITY_ACTIVE_CLAIM = "ACTIVE_CLAIM_BY_OTHER"
+ELIGIBILITY_CLEAR = "CLEAR"
+
+
+def assess_author_duplicate_work(
+    issue_number: int,
+    *,
+    stage: str,
+    open_prs: list[dict] | None = None,
+    branch_names: list[str] | None = None,
+    claim_entry: dict | None = None,
+    matching_branches: list[str] | None = None,
+    allow_stale_takeover: bool = False,
+) -> dict[str, Any]:
+    """Fail closed when duplicate work is detected before author mutations (#400)."""
+    stage_norm = (stage or "").strip().lower()
+    if stage_norm not in STAGES:
+        return {
+            "allowed": False,
+            "block": True,
+            "eligibility_class": "INVALID_STAGE",
+            "stage": stage_norm or None,
+            "reasons": [f"unknown duplicate-work stage {stage!r}"],
+            "safe_next_action": f"use one of: {', '.join(STAGES)}",
+        }
+
+    prs = list(open_prs or [])
+    linked_pr = _linked_open_pr(int(issue_number), prs)
+    branches = list(
+        matching_branches
+        if matching_branches is not None
+        else _matching_branch_names(int(issue_number), list(branch_names or []))
+    )
+
+    reasons: list[str] = []
+    eligibility = ELIGIBILITY_CLEAR
+
+    if linked_pr:
+        eligibility = ELIGIBILITY_OPEN_PR_EXISTS
+        reasons.append(
+            f"open PR #{linked_pr.get('number')} already covers issue "
+            f"#{issue_number}"
+        )
+
+    if branches and stage_norm in {"claim", "lock", "worktree", "edit"}:
+        if eligibility == ELIGIBILITY_CLEAR:
+            eligibility = ELIGIBILITY_DUPLICATE_BRANCH_EXISTS
+        reasons.append(
+            f"remote branch(es) already exist for issue #{issue_number}: "
+            f"{', '.join(branches)}"
+        )
+
+    entry = claim_entry or {}
+    claim_status = (entry.get("status") or "").strip()
+    if claim_status in {"active", "awaiting_review"} and stage_norm == "claim":
+        if entry.get("reclaimable") and allow_stale_takeover:
+            pass
+        elif claim_status == "active" and not entry.get("reclaimable"):
+            if eligibility == ELIGIBILITY_CLEAR:
+                eligibility = ELIGIBILITY_ACTIVE_CLAIM
+            reasons.append(
+                f"issue #{issue_number} has active claim "
+                f"(status={claim_status})"
+            )
+    elif claim_status == "awaiting_review" and stage_norm == "claim":
+        if not linked_pr:
+            reasons.append(
+                f"issue #{issue_number} is awaiting_review but no linked open PR "
+                "was supplied for duplicate-work proof"
+            )
+
+    allowed = not reasons
+    outcome = "duplicate_work_prevented" if not allowed else "clear"
+    if stage_norm == "create_pr" and not allowed:
+        outcome = "duplicate_pr_prevented"
+    elif stage_norm in {"commit", "push"} and not allowed:
+        outcome = "duplicate_push_prevented" if stage_norm == "push" else "duplicate_commit_prevented"
+
+    return {
+        "allowed": allowed,
+        "block": not allowed,
+        "eligibility_class": eligibility if not allowed else ELIGIBILITY_CLEAR,
+        "stage": stage_norm,
+        "linked_open_pr": linked_pr.get("number") if linked_pr else None,
+        "matching_branches": branches,
+        "claim_status": claim_status or None,
+        "outcome": outcome,
+        "reasons": reasons,
+        "safe_next_action": (
+            "stop without edits/commit/push/PR; produce reconciliation handoff "
+            "preserving local work only"
+            if not allowed
+            else "proceed"
+        ),
+    }
+
+
+def build_claim_entry_from_classification(classification: dict) -> dict:
+    """Map ``classify_issue_claim`` output to gate claim metadata."""
+    return {
+        "status": classification.get("status"),
+        "reclaimable": classification.get("reclaimable"),
+        "linked_open_pr": classification.get("linked_open_pr"),
+    }
+
+
+_DUPLICATE_OUTCOME_RE = re.compile(
+    r"(duplicate\s+(?:pr|branch|commit|push)\s+prevented|"
+    r"duplicate\s+work\s+not\s+prevented|reconciliation\s+handoff)",
+    re.IGNORECASE,
+)
+
+
+def assess_work_issue_duplicate_prevention_report(report_text: str) -> dict:
+    """#400: work-issue reports must state duplicate-work prevention outcome."""
+    text = report_text or ""
+    if "duplicate work" not in text.lower() and "duplicate pr" not in text.lower():
+        return {
+            "proven": True,
+            "block": False,
+            "reasons": [],
+            "safe_next_action": "proceed",
+        }
+    if _DUPLICATE_OUTCOME_RE.search(text):
+        return {
+            "proven": True,
+            "block": False,
+            "reasons": [],
+            "safe_next_action": "proceed",
+        }
+    return {
+        "proven": False,
+        "block": True,
+        "reasons": [
+            "duplicate-work discussion must name a prevention outcome "
+            "(duplicate PR/branch/commit/push prevented, or duplicate work "
+            "not prevented, or reconciliation handoff)"
+        ],
+        "safe_next_action": "state exact duplicate-work prevention class in final report",
+    }
+
+
+def classify_and_assess(
+    issue: dict,
+    *,
+    stage: str,
+    comments: list[dict] | None = None,
+    open_prs: list[dict] | None = None,
+    branch_names: list[str] | None = None,
+    allow_stale_takeover: bool = False,
+) -> dict[str, Any]:
+    """Combine claim classification with duplicate-work gate assessment."""
+    issue_number = int(issue.get("number") or 0)
+    claim = classify_issue_claim(
+        issue=issue,
+        comments=comments or [],
+        open_prs=open_prs or [],
+        branch_names=branch_names or [],
+    )
+    assessment = assess_author_duplicate_work(
+        issue_number,
+        stage=stage,
+        open_prs=open_prs,
+        branch_names=branch_names,
+        claim_entry=build_claim_entry_from_classification(claim),
+        matching_branches=claim.get("matching_branches"),
+        allow_stale_takeover=allow_stale_takeover,
+    )
+    return {
+        "issue_number": issue_number,
+        "claim": claim,
+        "duplicate_work": assessment,
+    }

final_report_validator.py

@@ -11,7 +11,6 @@ import inspect
 import re
 from typing import Any, Callable
 
-from post_merge_cleanup_proof import assess_post_merge_cleanup_proof
 from review_proofs import (
     HANDOFF_HEADING,
     assess_controller_handoff,
@@ -890,20 +889,6 @@ def _rule_reviewer_review_mutation(
     )
 
 
-def _rule_reviewer_post_merge_cleanup_proof(report_text: str) -> list[dict[str, str]]:
-    result = assess_post_merge_cleanup_proof(report_text)
-    if not result.get("block"):
-        return []
-    return _findings_from_reasons(
-        "reviewer.post_merge_cleanup_proof",
-        result.get("reasons") or [],
-        field="Cleanup status",
-        severity="block",
-        safe_next_action=result.get("safe_next_action")
-        or "report CLEANUP_SKIPPED with blocker or full cleanup checklist",
-    )
-
-
 _RULES_BY_TASK: dict[str, list[Callable[..., list[dict[str, str]]]]] = {
     "review_pr": [
         _rule_shared_controller_handoff,
@@ -924,7 +909,6 @@ _RULES_BY_TASK: dict[str, list[Callable[..., list[dict[str, str]]]]] = {
         _rule_reviewer_target_branch_freshness,
         _rule_reviewer_mutation_ledger,
         _rule_reviewer_review_mutation,
-        _rule_reviewer_post_merge_cleanup_proof,
     ],
     "reconcile_already_landed": [
         _rule_reconcile_controller_handoff,

gitea_mcp_server.py

@@ -503,6 +503,7 @@ import issue_lock_worktree  # noqa: E402
 import already_landed_reconcile  # noqa: E402
 import author_mutation_worktree  # noqa: E402
 import issue_claim_heartbeat  # noqa: E402
+import author_duplicate_work_gate  # noqa: E402
 import merged_cleanup_reconcile  # noqa: E402
 import reconciler_profile  # noqa: E402
 import reconciliation_workflow  # noqa: E402
@@ -1049,6 +1050,76 @@ def gitea_create_issue(
     return _with_optional_url({"number": data["number"]}, data.get("html_url"))
 
 
+def _list_repo_branch_names(h: str, o: str, r: str, auth: str, *, limit: int = 200) -> list[str]:
+    branches = api_get_all(f"{repo_api_url(h, o, r)}/branches", auth, limit=limit)
+    return [_branch_entry_name(branch) for branch in branches]
+
+
+def _gather_author_duplicate_work_context(
+    issue_number: int,
+    *,
+    h: str,
+    o: str,
+    r: str,
+    auth: str,
+    exclude_branch_name: str | None = None,
+) -> dict:
+    base = repo_api_url(h, o, r)
+    issue = api_request("GET", f"{base}/issues/{issue_number}", auth)
+    comments = api_request("GET", f"{base}/issues/{issue_number}/comments", auth) or []
+    open_prs = api_get_all(f"{base}/pulls?state=open", auth)
+    branch_names = _list_repo_branch_names(h, o, r, auth)
+    if exclude_branch_name:
+        branch_names = [
+            name for name in branch_names
+            if name != exclude_branch_name
+        ]
+    return {
+        "issue": issue,
+        "comments": comments,
+        "open_prs": open_prs,
+        "branch_names": branch_names,
+    }
+
+
+def _enforce_author_duplicate_work_gate(
+    issue_number: int,
+    stage: str,
+    *,
+    h: str,
+    o: str,
+    r: str,
+    auth: str,
+    allow_stale_takeover: bool = False,
+    exclude_branch_name: str | None = None,
+) -> dict:
+    """Fail closed when duplicate work is detected (#400)."""
+    ctx = _gather_author_duplicate_work_context(
+        issue_number,
+        h=h,
+        o=o,
+        r=r,
+        auth=auth,
+        exclude_branch_name=exclude_branch_name,
+    )
+    result = author_duplicate_work_gate.classify_and_assess(
+        ctx["issue"],
+        stage=stage,
+        comments=ctx["comments"],
+        open_prs=ctx["open_prs"],
+        branch_names=ctx["branch_names"],
+        allow_stale_takeover=allow_stale_takeover,
+    )
+    assessment = result.get("duplicate_work") or {}
+    if assessment.get("block"):
+        reasons = "; ".join(assessment.get("reasons") or ["duplicate work detected"])
+        raise RuntimeError(
+            f"Author duplicate-work gate (#400) blocked at stage '{stage}': "
+            f"{reasons} (fail closed)"
+        )
+    return result
+
+
 @mcp.tool()
 def gitea_lock_issue(
     issue_number: int,
@@ -1111,48 +1182,17 @@ def gitea_lock_issue(
             issue_lock_worktree.format_issue_lock_worktree_error(lock_assessment)
         )
 
-    # 2. Check if the issue already has an open PR (reuse protection)
     h, o, r = _resolve(remote, host, org, repo)
     auth = _auth(h)
-    url = f"{repo_api_url(h, o, r)}/pulls?state=open"
-
-    try:
-        prs = api_get_all(url, auth)
-    except Exception as e:
-        raise RuntimeError(f"Could not list open PRs to verify issue lock: {e}")
-
-    for pr in prs:
-        pr_head = pr.get("head", {}).get("ref", "")
-        pr_title = pr.get("title", "")
-        pr_body = pr.get("body", "")
-
-        if expected_pattern in pr_head:
-            raise ValueError(
-                f"Issue #{issue_number} is already tied to an open PR (PR #{pr.get('number')}, branch '{pr_head}') (fail closed)"
-            )
-
-        patterns = [
-            f"closes #{issue_number}",
-            f"fixes #{issue_number}",
-        ]
-        text_to_check = f"{pr_title} {pr_body}".lower()
-        if any(p in text_to_check for p in patterns):
-            raise ValueError(
-                f"Issue #{issue_number} is already tied to an open PR (PR #{pr.get('number')}) via Closes/Fixes reference (fail closed)"
-            )
-
-    branch_url = f"{repo_api_url(h, o, r)}/branches"
-    try:
-        branches = api_get_all(branch_url, auth)
-    except Exception as e:
-        raise RuntimeError(f"Could not list branches to verify issue lock: {e}")
-    for branch in branches:
-        name = _branch_entry_name(branch)
-        if expected_pattern in name:
-            raise ValueError(
-                f"Issue #{issue_number} already has matching branch '{name}' "
-                "(fail closed)"
-            )
+    _enforce_author_duplicate_work_gate(
+        issue_number,
+        "lock",
+        h=h,
+        o=o,
+        r=r,
+        auth=auth,
+        exclude_branch_name=branch_name,
+    )
 
     work_lease = _build_author_issue_work_lease(
         issue_number=issue_number,
@@ -1273,6 +1313,17 @@ def gitea_create_pr(
             f"PR head branch '{head}' does not match locked branch '{locked_branch}' (fail closed)"
         )
 
+    auth = _auth(h)
+    _enforce_author_duplicate_work_gate(
+        int(locked_issue),
+        "create_pr",
+        h=h,
+        o=o,
+        r=r,
+        auth=auth,
+        exclude_branch_name=locked_branch,
+    )
+
     # Check for forbidden terms anywhere in title/body
     forbidden_terms = ["equivalent", "related", "same as"]
     text_to_check = f"{title} {body}".lower()
@@ -1289,7 +1340,6 @@ def gitea_create_pr(
             f"PR title or body must contain 'Closes #{locked_issue}' or 'Fixes #{locked_issue}' exactly to ensure durable tracking (fail closed)"
         )
 
-    auth = _auth(h)
     url = f"{repo_api_url(h, o, r)}/pulls"
     payload = {"title": title, "body": body, "head": head, "base": base}
     meta = {"title": title, "head": head, "base": base}
@@ -6003,6 +6053,14 @@ def gitea_mark_issue(
         )
 
     if action == "start":
+        _enforce_author_duplicate_work_gate(
+            issue_number,
+            "claim",
+            h=h,
+            o=o,
+            r=r,
+            auth=auth,
+        )
         with _audited("label_issue", host=h, remote=remote, org=o, repo=r,
                       issue_number=issue_number,
                       request_metadata={"op": "add", "label": "status:in-progress"}):
@@ -6084,6 +6142,65 @@ def gitea_post_heartbeat(
     )
 
 
+@mcp.tool()
+def gitea_assess_author_duplicate_work(
+    issue_number: int,
+    stage: str,
+    remote: str = "dadeschools",
+    host: str | None = None,
+    org: str | None = None,
+    repo: str | None = None,
+    allow_stale_takeover: bool = False,
+    exclude_branch_name: str | None = None,
+) -> dict:
+    """Read-only: assess duplicate-work risk before author mutations (#400).
+
+    Call at claim, lock, worktree, edit, commit, push, and create_pr stages.
+    """
+    read_block = _profile_operation_gate("gitea.read")
+    if read_block:
+        return {
+            "success": False,
+            "reasons": read_block,
+            "permission_report": _permission_block_report("gitea.read"),
+        }
+    h, o, r = _resolve(remote, host, org, repo)
+    auth = _auth(h)
+    ctx = _gather_author_duplicate_work_context(
+        issue_number,
+        h=h,
+        o=o,
+        r=r,
+        auth=auth,
+        exclude_branch_name=exclude_branch_name,
+    )
+    result = author_duplicate_work_gate.classify_and_assess(
+        ctx["issue"],
+        stage=stage,
+        comments=ctx["comments"],
+        open_prs=ctx["open_prs"],
+        branch_names=ctx["branch_names"],
+        allow_stale_takeover=allow_stale_takeover,
+    )
+    assessment = result.get("duplicate_work") or {}
+    return {
+        "success": True,
+        "performed": False,
+        "issue_number": issue_number,
+        "stage": stage,
+        "allowed": assessment.get("allowed"),
+        "block": assessment.get("block"),
+        "eligibility_class": assessment.get("eligibility_class"),
+        "outcome": assessment.get("outcome"),
+        "linked_open_pr": assessment.get("linked_open_pr"),
+        "matching_branches": assessment.get("matching_branches"),
+        "claim_status": assessment.get("claim_status"),
+        "reasons": assessment.get("reasons"),
+        "safe_next_action": assessment.get("safe_next_action"),
+        "claim": result.get("claim"),
+    }
+
+
 @mcp.tool()
 def gitea_reconcile_issue_claims(
     state: str = "open",

post_merge_cleanup_proof.py

@@ -1,239 +0,0 @@
-"""Post-merge cleanup proof verifier for reviewer final reports (#402)."""
-
-from __future__ import annotations
-
-import re
-from typing import Any
-
-CLEANUP_SKIPPED = "CLEANUP_SKIPPED"
-CLEANUP_PERFORMED = "CLEANUP_PERFORMED"
-
-_CLEANUP_SECTION_HINT = re.compile(
-    r"(?:cleanup (?:status|result|mutations)|post-merge cleanup|"
-    r"gitea_delete_branch|remote branch.*deleted|worktree remove)",
-    re.IGNORECASE,
-)
-_CLEANUP_SKIPPED_RE = re.compile(r"\bCLEANUP_SKIPPED\b", re.IGNORECASE)
-_CLEANUP_BLOCKER_RE = re.compile(
-    r"(?:cleanup blocker|cleanup skip(?:ped)? reason)\s*:\s*(.+)",
-    re.IGNORECASE,
-)
-_REMOTE_DELETE_CLAIM_RE = re.compile(
-    r"(?:gitea_delete_branch|remote (?:head )?branch (?:was )?deleted|"
-    r"deleted remote branch|delete_branch)",
-    re.IGNORECASE,
-)
-_WORKTREE_REMOVE_CLAIM_RE = re.compile(
-    r"(?:git worktree remove|worktree (?:was )?removed|removed (?:local )?worktree|"
-    r"worktree cleanup performed)",
-    re.IGNORECASE,
-)
-_DELETE_CAPABILITY_RE = re.compile(
-    r"(?:delete[- ]branch capability resolved|gitea\.branch\.delete)\s*:\s*"
-    r".*(?:gitea\.branch\.delete|delete_branch).*(?:resolved|allowed|proven)|"
-    r"gitea\.branch\.delete\s+(?:resolved|allowed|proven)",
-    re.IGNORECASE,
-)
-_DELETE_TASK_RE = re.compile(
-    r"(?:delete_branch|cleanup_branch|reconcile_merged_cleanups)",
-    re.IGNORECASE,
-)
-_MERGE_RESULT_RE = re.compile(
-    r"merge result\s*:\s*(?:merged|success|performed)",
-    re.IGNORECASE,
-)
-_MERGE_COMMIT_SHA_RE = re.compile(
-    r"(?:merge commit sha|merged commit sha|merge commit)\s*:\s*([0-9a-f]{7,40})",
-    re.IGNORECASE,
-)
-_PR_HEAD_BRANCH_RE = re.compile(
-    r"(?:merged pr head branch|pr head branch|deleted branch)\s*:\s*(\S+)",
-    re.IGNORECASE,
-)
-_BRANCH_NOT_PROTECTED_RE = re.compile(
-    r"branch (?:is )?not protected|branch protection\s*:\s*(?:none|false|no)",
-    re.IGNORECASE,
-)
-_OPEN_PR_INVENTORY_RE = re.compile(
-    r"(?:no other open pr(?:\s+references)?(?:\s+\S+)?|open pr inventory proof|"
-    r"open pr references).*(?:none|zero|0|clear|inventory complete)|"
-    r"no other open pr references branch",
-    re.IGNORECASE,
-)
-_ACTIVE_CLAIM_LEASE_RE = re.compile(
-    r"(?:no active (?:heartbeat|claim|lease)|"
-    r"(?:active )?(?:heartbeat|claim|lease)(?:/(?:claim|lease))*\s*:\s*none)",
-    re.IGNORECASE,
-)
-_SESSION_OWNED_WORKTREE_RE = re.compile(
-    r"(?:removed worktree path|cleanup worktree path|session-owned worktree)\s*:\s*(\S+)",
-    re.IGNORECASE,
-)
-_BRANCHES_PATH_RE = re.compile(r"\bbranches/", re.IGNORECASE)
-_CLEAN_TRACKED_RE = re.compile(
-    r"(?:pre-removal tracked state|tracked state before removal)\s*:\s*clean",
-    re.IGNORECASE,
-)
-_CLEAN_UNTRACKED_RE = re.compile(
-    r"(?:pre-removal untracked state|untracked state before removal)\s*:\s*clean",
-    re.IGNORECASE,
-)
-_WORKTREE_LIST_AFTER_RE = re.compile(
-    r"(?:git worktree list after|post-removal worktree list|worktree list after)",
-    re.IGNORECASE,
-)
-_WRONG_BRANCH_RE = re.compile(
-    r"deleted branch (?:does not match|!=|differs from) (?:merged )?pr head",
-    re.IGNORECASE,
-)
-
-
-def _claims_remote_delete(text: str) -> bool:
-    return bool(_REMOTE_DELETE_CLAIM_RE.search(text))
-
-
-def _claims_worktree_remove(text: str) -> bool:
-    return bool(_WORKTREE_REMOVE_CLAIM_RE.search(text))
-
-
-def _branch_safety_fields_present(text: str) -> list[str]:
-    missing: list[str] = []
-    if not _DELETE_CAPABILITY_RE.search(text):
-        missing.append("delete-branch capability resolved (gitea.branch.delete)")
-    if not _DELETE_TASK_RE.search(text):
-        missing.append("delete-branch task named (delete_branch or cleanup)")
-    if not _MERGE_RESULT_RE.search(text):
-        missing.append("merge result: merged")
-    if not _MERGE_COMMIT_SHA_RE.search(text):
-        missing.append("merge commit SHA")
-    if not _PR_HEAD_BRANCH_RE.search(text):
-        missing.append("merged PR head branch / deleted branch name")
-    if not _BRANCH_NOT_PROTECTED_RE.search(text):
-        missing.append("branch not protected proof")
-    if not _OPEN_PR_INVENTORY_RE.search(text):
-        missing.append("open PR inventory proof (no other PR references branch)")
-    if not _ACTIVE_CLAIM_LEASE_RE.search(text):
-        missing.append("no active heartbeat/claim/lease proof")
-    return missing
-
-
-def _worktree_cleanup_fields_present(text: str) -> list[str]:
-    missing: list[str] = []
-    match = _SESSION_OWNED_WORKTREE_RE.search(text)
-    path = match.group(1).strip() if match else ""
-    if not path:
-        missing.append("session-owned worktree path")
-    elif not _BRANCHES_PATH_RE.search(path.replace("\\", "/")):
-        missing.append("worktree path under branches/")
-    if not _CLEAN_TRACKED_RE.search(text):
-        missing.append("pre-removal tracked state: clean")
-    if not _CLEAN_UNTRACKED_RE.search(text):
-        missing.append("pre-removal untracked state: clean")
-    if not _WORKTREE_LIST_AFTER_RE.search(text):
-        missing.append("git worktree list after removal")
-    return missing
-
-
-def assess_post_merge_cleanup_proof(
-    report_text: str,
-    *,
-    cleanup_session: dict | None = None,
-) -> dict[str, Any]:
-    """Validate post-merge cleanup claims carry safety-gate proof (#402)."""
-    text = report_text or ""
-    session = dict(cleanup_session or {})
-    reasons: list[str] = []
-
-    if _CLEANUP_SKIPPED_RE.search(text) or session.get("outcome") == CLEANUP_SKIPPED:
-        blocker = (session.get("blocker") or "").strip()
-        if not blocker:
-            match = _CLEANUP_BLOCKER_RE.search(text)
-            blocker = match.group(1).strip() if match else ""
-        if blocker.upper() == CLEANUP_SKIPPED:
-            blocker = ""
-        if not blocker:
-            reasons.append(
-                "CLEANUP_SKIPPED requires exact cleanup blocker reason (#402)"
-            )
-        return {
-            "block": bool(reasons),
-            "proven": not reasons,
-            "outcome": CLEANUP_SKIPPED,
-            "remote_delete_claimed": False,
-            "worktree_remove_claimed": False,
-            "reasons": reasons,
-            "safe_next_action": (
-                "report CLEANUP_SKIPPED with exact blocker; do not claim performed cleanup"
-                if reasons
-                else "proceed"
-            ),
-        }
-
-    if not _CLEANUP_SECTION_HINT.search(text) and not session.get("cleanup_claimed"):
-        return {
-            "block": False,
-            "proven": True,
-            "outcome": None,
-            "remote_delete_claimed": False,
-            "worktree_remove_claimed": False,
-            "reasons": [],
-            "safe_next_action": "proceed",
-        }
-
-    remote_delete = bool(
-        session.get("remote_delete_claimed") or _claims_remote_delete(text)
-    )
-    worktree_remove = bool(
-        session.get("worktree_remove_claimed") or _claims_worktree_remove(text)
-    )
-
-    if _WRONG_BRANCH_RE.search(text):
-        reasons.append(
-            "cleanup report claims deleted branch that is not the merged PR head branch"
-        )
-
-    if remote_delete:
-        reasons.extend(
-            f"remote branch deletion missing {field}"
-            for field in _branch_safety_fields_present(text)
-        )
-
-    if worktree_remove:
-        reasons.extend(
-            f"worktree removal missing {field}"
-            for field in _worktree_cleanup_fields_present(text)
-        )
-
-    if (remote_delete or worktree_remove) and not (remote_delete or worktree_remove):
-        pass
-
-    if not remote_delete and not worktree_remove:
-        cleanup_mutations = re.search(
-            r"cleanup mutations\s*:\s*(?!none\b)\S",
-            text,
-            re.IGNORECASE,
-        )
-        if cleanup_mutations:
-            reasons.append(
-                "cleanup mutations reported without post-merge cleanup proof checklist"
-            )
-
-    outcome = CLEANUP_PERFORMED if (remote_delete or worktree_remove) and not reasons else None
-    if remote_delete or worktree_remove:
-        outcome = CLEANUP_PERFORMED if not reasons else "CLEANUP_CLAIMED_UNPROVEN"
-
-    block = bool(reasons)
-    return {
-        "block": block,
-        "proven": not block,
-        "outcome": outcome,
-        "remote_delete_claimed": remote_delete,
-        "worktree_remove_claimed": worktree_remove,
-        "reasons": reasons,
-        "safe_next_action": (
-            "report CLEANUP_SKIPPED with exact blocker or include the full cleanup "
-            "checklist before claiming remote delete or worktree removal"
-            if reasons
-            else "proceed"
-        ),
-    }

review_proofs.py

@@ -3622,18 +3622,33 @@ def assess_work_issue_mode_isolation(report_text: str) -> dict:
     }
 
 
+def assess_work_issue_duplicate_prevention_report(report_text, **kwargs):
+    """#400: work-issue reports must classify duplicate-work prevention."""
+    from author_duplicate_work_gate import (
+        assess_work_issue_duplicate_prevention_report as _assess,
+    )
+
+    return _assess(report_text, **kwargs)
+
+
 def assess_work_issue_final_report(report_text: str) -> dict:
     """#139: composite verifier for work-issue final reports."""
     checks = {
         "workflow_source": assess_work_issue_workflow_source(report_text),
         "mode_isolation": assess_work_issue_mode_isolation(report_text),
+        "duplicate_prevention": assess_work_issue_duplicate_prevention_report(
+            report_text
+        ),
     }
 
     reasons = []
     downgraded = False
     for name, result in checks.items():
         verdict = result.get("verdict")
-        if verdict in ("missing", "incomplete"):
+        if result.get("block"):
+            downgraded = True
+            reasons.extend(result.get("reasons") or [])
+        elif verdict in ("missing", "incomplete"):
             downgraded = True
             reasons.extend(result.get("reasons") or [])
         elif result.get("downgraded") or not result.get("complete", True):
@@ -3641,6 +3656,9 @@ def assess_work_issue_final_report(report_text: str) -> dict:
             reasons.extend(
                 f"{name}: {r}" for r in (result.get("reasons") or [])
             )
+        elif result.get("proven") is False:
+            downgraded = True
+            reasons.extend(result.get("reasons") or [])
 
     grade = "A" if not downgraded else "downgraded"
     return {

skills/llm-project-workflow/workflows/review-merge-pr.md

@@ -797,40 +797,6 @@ Do not update the main checkout if merge failed, was blocked, or produced reconc
 
 If any local artifact is created after final cleanup, run and report a new final status check.
 
-## 28A. Post-merge cleanup proof checklist (#402)
-
-Successful tool execution is not proof that cleanup was authorized. Before claiming remote branch deletion or local worktree removal, the final report must carry the full safety checklist below. If any gate is missing, report `CLEANUP_SKIPPED` with the exact blocker — never perform cleanup and never claim it was performed.
-
-### Remote branch deletion checklist
-
-When `gitea_delete_branch` (or equivalent) deletes the merged PR head branch, report:
-
-* Delete-branch capability resolved: name the task (`delete_branch` / `cleanup_branch` / `reconcile_merged_cleanups`) and permission (`gitea.branch.delete`) with resolver proof before the delete call
-* Merge result: merged
-* Merge commit SHA: full 40-character SHA
-* Merged PR head branch / deleted branch: exact branch name (must match)
-* Branch protection: none / branch is not protected
-* Open PR inventory proof: no other open PR references the branch
-* Active heartbeat/claim/lease: none
-
-### Local worktree removal checklist
-
-When removing session-owned review/simulation worktrees under `branches/`, report:
-
-* Session-owned worktree path: exact path under `branches/`
-* Pre-removal tracked state: clean
-* Pre-removal untracked state: clean
-* Git worktree list after removal: command output or equivalent proof
-
-### Skipped cleanup
-
-If any gate fails, report:
-
-* Cleanup outcome: `CLEANUP_SKIPPED`
-* Cleanup blocker: exact missing gate (for example `gitea.branch.delete capability not resolved`)
-
-Skipped cleanup with an exact blocker passes validation. Performed-cleanup claims without the checklist fail validation.
-
 ## 29. Recovery handoff rules
 
 If blocked, produce a recovery handoff with:

skills/llm-project-workflow/workflows/work-issue.md

@@ -277,6 +277,24 @@ Do not select an issue based only on memory from a previous session.
 
 Before claiming or working on an issue, check whether there is already an open PR, branch, or active claim for that issue.
 
+Run `gitea_assess_author_duplicate_work` at these stages and stop when `block` is true:
+
+* `claim` — before `gitea_mark_issue`
+* `lock` — before `gitea_lock_issue`
+* `worktree` / `edit` — before creating a worktree or editing files
+* `commit` — immediately before `git commit`
+* `push` — immediately before `git push`
+* `create_pr` — immediately before `gitea_create_pr` (also enforced server-side)
+
+`gitea_mark_issue`, `gitea_lock_issue`, and `gitea_create_pr` enforce the same gate server-side and fail closed.
+
+If a concurrent open PR appears after work begins:
+
+* before commit or push — stop and preserve local work without pushing
+* after push but before PR creation — produce a reconciliation handoff instead of opening a PR
+
+Final reports must name the duplicate-work outcome (`duplicate PR prevented`, `duplicate branch prevented`, `duplicate commit prevented`, `duplicate push prevented`, `duplicate work not prevented`, or `reconciliation handoff`).
+
 If an open PR already exists for the issue, do not implement duplicate work.
 
 Classify the issue as:

tests/test_author_duplicate_work_gate.py

@@ -0,0 +1,102 @@
+"""Tests for early author duplicate-work gate (#400)."""
+import sys
+import unittest
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+from author_duplicate_work_gate import (  # noqa: E402
+    ELIGIBILITY_OPEN_PR_EXISTS,
+    assess_author_duplicate_work,
+    assess_work_issue_duplicate_prevention_report,
+)
+
+
+def _open_pr(number: int = 397, issue: int = 395) -> dict:
+    return {
+        "number": number,
+        "head": {"ref": f"feat/issue-{issue}-example"},
+        "title": f"feat: example (Closes #{issue})",
+        "body": f"Closes #{issue}",
+    }
+
+
+class TestAuthorDuplicateWorkGate(unittest.TestCase):
+    def test_clear_when_no_duplicates(self):
+        result = assess_author_duplicate_work(
+            400,
+            stage="claim",
+            open_prs=[],
+            branch_names=["master", "feat/issue-399-other"],
+        )
+        self.assertTrue(result["allowed"])
+        self.assertFalse(result["block"])
+
+    def test_open_pr_blocks_claim(self):
+        result = assess_author_duplicate_work(
+            395,
+            stage="claim",
+            open_prs=[_open_pr()],
+            branch_names=[],
+        )
+        self.assertFalse(result["allowed"])
+        self.assertEqual(result["eligibility_class"], ELIGIBILITY_OPEN_PR_EXISTS)
+
+    def test_matching_branch_blocks_lock_not_create_pr(self):
+        branches = ["feat/issue-400-early-duplicate-work-gate"]
+        lock = assess_author_duplicate_work(
+            400,
+            stage="lock",
+            open_prs=[],
+            branch_names=branches,
+        )
+        self.assertFalse(lock["allowed"])
+
+        create_pr = assess_author_duplicate_work(
+            400,
+            stage="create_pr",
+            open_prs=[],
+            branch_names=branches,
+            matching_branches=[],
+        )
+        self.assertTrue(create_pr["allowed"])
+
+    def test_open_pr_blocks_create_pr_stage(self):
+        result = assess_author_duplicate_work(
+            395,
+            stage="create_pr",
+            open_prs=[_open_pr()],
+            branch_names=["feat/issue-395-proof-backed-review-handoff"],
+        )
+        self.assertFalse(result["allowed"])
+        self.assertEqual(result["outcome"], "duplicate_pr_prevented")
+
+    def test_push_stage_blocks_on_concurrent_pr(self):
+        result = assess_author_duplicate_work(
+            395,
+            stage="push",
+            open_prs=[_open_pr()],
+            branch_names=[],
+        )
+        self.assertFalse(result["allowed"])
+        self.assertEqual(result["outcome"], "duplicate_push_prevented")
+
+    def test_duplicate_prevention_report_requires_outcome(self):
+        bad = assess_work_issue_duplicate_prevention_report(
+            "Duplicate work detected for issue #395."
+        )
+        self.assertFalse(bad["proven"])
+
+        good = assess_work_issue_duplicate_prevention_report(
+            "Duplicate PR prevented; reconciliation handoff produced."
+        )
+        self.assertTrue(good["proven"])
+
+    def test_exported_from_review_proofs(self):
+        from review_proofs import assess_work_issue_duplicate_prevention_report as exported
+
+        self.assertTrue(callable(exported))
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_llm_workflow_split.py

@@ -95,6 +95,12 @@ def test_create_issue_workflow_contract():
     assert "## 9. Duplicate search before mutation" in text
 
 
+def test_author_duplicate_work_gate_exported():
+    from review_proofs import assess_work_issue_duplicate_prevention_report
+
+    assert callable(assess_work_issue_duplicate_prevention_report)
+
+
 def test_work_issue_workflow_contract():
     text = (SKILL_DIR / "workflows" / "work-issue.md").read_text(encoding="utf-8")
     assert "canonical: true" in text

tests/test_post_merge_cleanup_proof.py

@@ -1,169 +0,0 @@
-"""Tests for post-merge cleanup proof enforcement (#402)."""
-import sys
-import unittest
-from pathlib import Path
-
-sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
-
-from final_report_validator import assess_final_report_validator  # noqa: E402
-from post_merge_cleanup_proof import (  # noqa: E402
-    CLEANUP_SKIPPED,
-    assess_post_merge_cleanup_proof,
-)
-
-MERGE_SHA = "a" * 40
-HEAD_BRANCH = "feat/issue-274-branches-only-worktrees"
-WORKTREE = "branches/review-pr374-conflicts"
-
-
-def _full_remote_cleanup_report(**overrides):
-    fields = {
-        "Task": "review PR #374",
-        "Merge result": "merged",
-        "Merge commit SHA": MERGE_SHA,
-        "Cleanup status": "remote branch deleted",
-        "Delete-branch capability resolved": "gitea.branch.delete allowed via delete_branch task",
-        "Merged PR head branch": HEAD_BRANCH,
-        "Deleted branch": HEAD_BRANCH,
-        "Branch protection": "none",
-        "Open PR inventory proof": "no other open PR references branch (inventory complete)",
-        "Active heartbeat/claim/lease": "none",
-        "Cleanup mutations": "gitea_delete_branch on remote head branch",
-    }
-    fields.update(overrides)
-    lines = ["## Controller Handoff", ""]
-    lines.extend(f"- {key}: {value}" for key, value in fields.items())
-    return "\n".join(lines)
-
-
-def _full_worktree_cleanup_report(**overrides):
-    fields = {
-        "Task": "review PR #374",
-        "Merge result": "merged",
-        "Cleanup status": "local worktree removed",
-        "Removed worktree path": WORKTREE,
-        "Pre-removal tracked state": "clean",
-        "Pre-removal untracked state": "clean",
-        "Git worktree list after removal": "only main checkout listed",
-        "Cleanup mutations": "git worktree remove on session-owned review worktree",
-    }
-    fields.update(overrides)
-    lines = ["## Controller Handoff", ""]
-    lines.extend(f"- {key}: {value}" for key, value in fields.items())
-    return "\n".join(lines)
-
-
-class TestPostMergeCleanupProof(unittest.TestCase):
-    def test_no_cleanup_claim_passes(self):
-        report = "## Controller Handoff\n- Task: review PR #1\n- Merge result: merged"
-        result = assess_post_merge_cleanup_proof(report)
-        self.assertFalse(result["block"])
-
-    def test_missing_capability_proof_blocked(self):
-        report = _full_remote_cleanup_report(
-            **{"Delete-branch capability resolved": "delete succeeded"}
-        )
-        result = assess_post_merge_cleanup_proof(report)
-        self.assertTrue(result["block"])
-        self.assertTrue(any("capability" in r.lower() for r in result["reasons"]))
-
-    def test_unmerged_pr_blocked(self):
-        report = _full_remote_cleanup_report(**{"Merge result": "not merged"})
-        result = assess_post_merge_cleanup_proof(report)
-        self.assertTrue(result["block"])
-        self.assertTrue(any("merge result" in r.lower() for r in result["reasons"]))
-
-    def test_wrong_branch_blocked(self):
-        report = _full_remote_cleanup_report(
-            **{"Deleted branch": "feat/other-branch"}
-        )
-        report += "\nDeleted branch does not match merged PR head branch"
-        result = assess_post_merge_cleanup_proof(report)
-        self.assertTrue(result["block"])
-
-    def test_protected_branch_blocked(self):
-        report = _full_remote_cleanup_report(**{"Branch protection": "enabled"})
-        result = assess_post_merge_cleanup_proof(report)
-        self.assertTrue(result["block"])
-
-    def test_open_pr_reference_blocked(self):
-        report = _full_remote_cleanup_report(
-            **{"Open PR inventory proof": "PR #999 still references branch"}
-        )
-        result = assess_post_merge_cleanup_proof(report)
-        self.assertTrue(result["block"])
-
-    def test_active_claim_blocked(self):
-        report = _full_remote_cleanup_report(
-            **{"Active heartbeat/claim/lease": "status:in-progress on linked issue"}
-        )
-        result = assess_post_merge_cleanup_proof(report)
-        self.assertTrue(result["block"])
-
-    def test_dirty_worktree_blocked(self):
-        report = _full_worktree_cleanup_report(
-            **{"Pre-removal tracked state": "dirty"}
-        )
-        result = assess_post_merge_cleanup_proof(report)
-        self.assertTrue(result["block"])
-        self.assertTrue(any("tracked" in r.lower() for r in result["reasons"]))
-
-    def test_foreign_worktree_blocked(self):
-        report = _full_worktree_cleanup_report(
-            **{"Removed worktree path": "/tmp/foreign-worktree"}
-        )
-        result = assess_post_merge_cleanup_proof(report)
-        self.assertTrue(result["block"])
-        self.assertTrue(any("branches/" in r.lower() for r in result["reasons"]))
-
-    def test_cleanup_skipped_with_blocker_passes(self):
-        report = "\n".join([
-            "## Controller Handoff",
-            "- Cleanup outcome: CLEANUP_SKIPPED",
-            "- Cleanup blocker: gitea.branch.delete capability not resolved in active profile",
-        ])
-        result = assess_post_merge_cleanup_proof(report)
-        self.assertFalse(result["block"])
-        self.assertEqual(result["outcome"], CLEANUP_SKIPPED)
-
-    def test_cleanup_skipped_without_blocker_blocked(self):
-        report = "## Controller Handoff\n- Cleanup outcome: CLEANUP_SKIPPED"
-        result = assess_post_merge_cleanup_proof(report)
-        self.assertTrue(result["block"])
-
-    def test_full_remote_cleanup_passes(self):
-        result = assess_post_merge_cleanup_proof(_full_remote_cleanup_report())
-        self.assertFalse(result["block"])
-        self.assertTrue(result["remote_delete_claimed"])
-
-    def test_full_worktree_cleanup_passes(self):
-        result = assess_post_merge_cleanup_proof(_full_worktree_cleanup_report())
-        self.assertFalse(result["block"])
-        self.assertTrue(result["worktree_remove_claimed"])
-
-    def test_validator_integration_blocks_unproven_delete(self):
-        report = (
-            "## Controller Handoff\n"
-            "- Cleanup mutations: gitea_delete_branch deleted remote branch\n"
-        )
-        result = assess_final_report_validator(report, task_kind="review_pr")
-        self.assertTrue(result["blocked"])
-        rule_ids = [f["rule_id"] for f in result["findings"]]
-        self.assertIn("reviewer.post_merge_cleanup_proof", rule_ids)
-
-    def test_validator_integration_allows_skipped(self):
-        report = "\n".join([
-            "## Controller Handoff",
-            "- Cleanup outcome: CLEANUP_SKIPPED",
-            "- Cleanup blocker: branch still referenced by open PR #414",
-        ])
-        result = assess_final_report_validator(report, task_kind="review_pr")
-        cleanup_findings = [
-            f for f in result["findings"]
-            if f["rule_id"] == "reviewer.post_merge_cleanup_proof"
-        ]
-        self.assertEqual(cleanup_findings, [])
-
-
-if __name__ == "__main__":
-    unittest.main()