diff --git a/.custodian-brief.md b/.custodian-brief.md
index bd1bee5..45c2340 100644
--- a/.custodian-brief.md
+++ b/.custodian-brief.md
@@ -2,20 +2,19 @@
 # Custodian Brief — rein-aharness
 
 **Domain:** agents  
-**Last synced:** 2026-10-13 20:53 UTC  
+**Last synced:** 2026-10-13 21:14 UTC  
 **State Hub:** http://127.0.0.1:8000 *(adjust if running on a remote machine)*
 
 ## Active Workstreams
 
 ### Simpler metered retry: free rehearsal, zero-cost hold release, one-command renewal
-Progress: 0/7 done  |  workplan_id: `187c2599-84a6-5764-a14f-7e9121975bf2`
+Progress: 1/7 done  |  workplan_id: `187c2599-84a6-5764-a14f-7e9121975bf2`
 
 **Open tasks:**
 - ! C. Envelopes that cover several attempts (decision)  `898e02af`
 - ! E. Ship the owner runtime as a container image (decision)  `b486e86b`
 - ! F. Approvals per envelope (decision)  `4cf721e6`
 - ! Retry on the corrected runtime  `80318842`
-- · A. Free rehearsal on the host  `c6536c8d`
 - · B. Release holds that provably cost nothing  `6a413f5a`
 - · D. One owner command for renewal  `87457216`
 
diff --git a/docs/owner-bootstrap.md b/docs/owner-bootstrap.md
index 8477769..084721f 100644
--- a/docs/owner-bootstrap.md
+++ b/docs/owner-bootstrap.md
@@ -23,6 +23,30 @@ first line of each launcher; the rehearsal executes them. Run 6efa9436
 
     python -I -B -m rein_aharness.cli metered-once --owner-config /abs/owner.json --rehearse
 
+**Renew an envelope with one command.** After the old envelope is
+reconciled (no `held` reservation, no open request route), write a small
+JSON file with only the fields that change: `envelope_id` (required and new),
+plus any of `authority_ref`, `valid_from`, `expires_at`, `eur_per_usd`,
+`per_run_eur`, `daily_eur`, `total_eur`, `max_budget_usd` and
+`max_liability_usd`. Then:
+
+    python -I -B -m rein_aharness.cli owner renew --owner-config /abs/owner.json \
+      --policy /abs/spend-policy.json --ledger /abs/spend.sqlite3 \
+      --runtime-path /abs/runtimes/<digest> --envelope envelope.json
+
+Without `--apply` this only prints the summary: envelope, policy and runtime
+digests from old to new, the limits, and where the old ledger goes. With
+`--apply` it:
+
+- backs up `owner.json` and the policy as `<name>.<old envelope>.bak`;
+- renames the old ledger to `<ledger>.retired-<old envelope>`;
+- initializes a fresh ledger at the same path;
+- writes the new policy and `owner.json` privately and atomically.
+
+No digest is typed by hand. Paths do not change, so the Secrets Engine
+`exec_owner` catalog needs only the new file hashes, which are printed as
+`catalog_file_pins`. Update those pins, then run `--rehearse`.
+
 Use the standalone candidate interpreter as `python -I -B -m rein_aharness.cli`.
 `-I` excludes editable PYTHONPATH/user-site fallbacks; `-B` prevents bytecode writes
 from changing the complete artifact digest. The source and namespace rein commands
diff --git a/rein_aharness/cli.py b/rein_aharness/cli.py
index 08bf89f..7c70d2d 100644
--- a/rein_aharness/cli.py
+++ b/rein_aharness/cli.py
@@ -611,6 +611,17 @@ def main(argv: list[str] | None = None) -> int:
         help="Skip the read-only Activity Core queue probe",
     )
 
+    owner = sub.add_parser("owner", help="Owner actions on the metered runtime")
+    owner.add_argument("action", choices=("renew",))
+    owner.add_argument("--owner-config", type=Path, required=True)
+    owner.add_argument("--policy", type=Path, required=True)
+    owner.add_argument("--ledger", type=Path, required=True)
+    owner.add_argument("--runtime-path", type=Path, required=True)
+    owner.add_argument("--envelope", type=Path, required=True,
+                       help="JSON with only the envelope fields that change")
+    owner.add_argument("--apply", action="store_true",
+                       help="Write the renewal; without it, print the summary only")
+
     spend = sub.add_parser("spend", help="Inspect or reconcile private worker spend reservations")
     spend.add_argument("action", choices=("init", "status", "reconcile"))
     spend.add_argument("--policy", type=Path, required=True)
@@ -638,6 +649,20 @@ def main(argv: list[str] | None = None) -> int:
     if args.command == "claim-loop":
         return _cmd_claim_loop(args)
 
+    if args.command == "owner":
+        from rein_aharness.owner_renew import RenewalRefused, apply, plan, summary
+        try:
+            renewal = plan(args.owner_config, args.policy, args.ledger,
+                           args.runtime_path, args.envelope)
+            result = {"ok": True, "dry_run": not args.apply, **summary(renewal)}
+            if args.apply:
+                result.update(apply(renewal))
+        except RenewalRefused as exc:
+            print(json.dumps({"ok": False, "refused": str(exc)}))
+            return 2
+        print(json.dumps(result, indent=2))
+        return 0
+
     if args.command == "close-outbox":
         return _cmd_close_outbox(args)
 
diff --git a/rein_aharness/owner_renew.py b/rein_aharness/owner_renew.py
new file mode 100644
index 0000000..59e5b39
--- /dev/null
+++ b/rein_aharness/owner_renew.py
@@ -0,0 +1,161 @@
+"""One owner command to renew a metered envelope (REINAH-WP-0008-T03).
+
+Renewal used to mean editing the spend policy, initializing a ledger and
+updating five digests in owner.json by hand. This command does it in one
+reviewed step: dry run by default, ``apply`` only on request.
+
+Paths stay the same so that the Secrets Engine catalog only needs new file
+hashes, not new paths. The old ledger is renamed, never reset; the old policy
+and owner.json are kept as backups.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import json
+import os
+import sqlite3
+from dataclasses import replace
+from pathlib import Path
+from typing import Any
+
+from rein_aharness.request_admission import RequestLedger
+from rein_aharness.spend_admission import (
+    SpendAdmissionError,
+    SpendLedger,
+    SpendPolicy,
+    _private_file,
+)
+
+# Fields an envelope may change. Worker, target, profile and grant pins carry
+# over unchanged; changing those is a different admission, not a renewal.
+ENVELOPE_FIELDS = frozenset({
+    "envelope_id", "authority_ref", "valid_from", "expires_at",
+    "eur_per_usd", "per_run_eur", "daily_eur", "total_eur",
+    "max_budget_usd", "max_liability_usd",
+})
+_OWNER_KEYS = {"version", "authority_ref", "spend_policy_sha256", "messages_policy", "runtime"}
+
+
+class RenewalRefused(RuntimeError):
+    pass
+
+
+def _file_sha256(path: Path) -> str:
+    return hashlib.sha256(path.read_bytes()).hexdigest()
+
+
+def _write_private(path: Path, text: str) -> None:
+    temporary = path.with_name(f".{path.name}.renew")
+    fd = os.open(temporary, os.O_CREAT | os.O_EXCL | os.O_WRONLY, 0o600)
+    with os.fdopen(fd, "w") as stream:
+        stream.write(text)
+        stream.flush()
+        os.fsync(stream.fileno())
+    os.replace(temporary, path)
+
+
+def _ledger_settled(ledger: Path) -> None:
+    for suffix in ("-journal", "-wal"):
+        if Path(f"{ledger}{suffix}").exists():
+            raise RenewalRefused("ledger has an open transaction")
+    db = sqlite3.connect(f"file:{ledger}?mode=ro", uri=True)
+    try:
+        if db.execute("SELECT count(*) FROM reservations WHERE state='held'").fetchone()[0]:
+            raise RenewalRefused("ledger has a held reservation; reconcile it first")
+        if db.execute("SELECT count(*) FROM request_routes WHERE revoked=0").fetchone()[0]:
+            raise RenewalRefused("ledger has an open request route")
+    except sqlite3.Error:
+        raise RenewalRefused("ledger is unreadable") from None
+    finally:
+        db.close()
+
+
+def plan(owner_config: Path, policy_path: Path, ledger_path: Path,
+         runtime_path: Path, envelope_path: Path) -> dict[str, Any]:
+    """Validate everything and return the renewal; change nothing."""
+    from sandboxer.extensions.runtime import runtime_digest
+
+    for path in (owner_config, policy_path, ledger_path, runtime_path):
+        if not path.is_absolute() or path.resolve() != path:
+            raise RenewalRefused("paths must be absolute and canonical")
+    try:
+        _private_file(owner_config)
+        _private_file(ledger_path)
+        old_policy = SpendPolicy.load(policy_path)
+    except SpendAdmissionError as exc:
+        raise RenewalRefused(str(exc)) from None
+    owner = json.loads(owner_config.read_text())
+    if set(owner) != _OWNER_KEYS or owner["spend_policy_sha256"] != old_policy.sha256:
+        raise RenewalRefused("owner.json does not match the current spend policy")
+    _ledger_settled(ledger_path)
+
+    envelope = json.loads(envelope_path.read_text())
+    if not isinstance(envelope, dict) or not envelope or set(envelope) - ENVELOPE_FIELDS:
+        raise RenewalRefused(
+            f"envelope may only set: {', '.join(sorted(ENVELOPE_FIELDS))}")
+    if envelope.get("envelope_id", old_policy.envelope_id) == old_policy.envelope_id:
+        raise RenewalRefused("renewal needs a new envelope_id")
+    try:
+        new_policy = replace(old_policy, **envelope)
+    except (SpendAdmissionError, TypeError) as exc:
+        raise RenewalRefused(f"new spend policy invalid: {exc}") from None
+
+    if not (runtime_path / "bin").is_dir():
+        raise RenewalRefused("runtime path is not a runtime")
+    runtime_sha256 = runtime_digest(runtime_path)
+    new_owner = {**owner, "authority_ref": new_policy.authority_ref,
+                 "spend_policy_sha256": new_policy.sha256,
+                 "runtime": {"path": str(runtime_path), "sha256": runtime_sha256}}
+    return {
+        "owner_config": owner_config, "policy_path": policy_path, "ledger_path": ledger_path,
+        "old_policy": old_policy, "new_policy": new_policy,
+        "old_owner": owner, "new_owner": new_owner,
+        "retired_ledger": ledger_path.with_name(
+            f"{ledger_path.name}.retired-{old_policy.envelope_id}"),
+    }
+
+
+def summary(renewal: dict[str, Any]) -> dict[str, Any]:
+    old, new = renewal["old_policy"], renewal["new_policy"]
+    return {
+        "envelope": {"from": old.envelope_id, "to": new.envelope_id},
+        "spend_policy_sha256": {"from": old.sha256, "to": new.sha256},
+        "runtime_sha256": {"from": renewal["old_owner"]["runtime"]["sha256"],
+                           "to": renewal["new_owner"]["runtime"]["sha256"]},
+        "limits": {name: getattr(new, name) for name in sorted(ENVELOPE_FIELDS - {"envelope_id"})},
+        "ledger": {"path": str(renewal["ledger_path"]),
+                   "old_retired_to": str(renewal["retired_ledger"])},
+    }
+
+
+def apply(renewal: dict[str, Any]) -> dict[str, Any]:
+    """Back up, retire the old ledger, write new files; return catalog pins."""
+    owner_config, policy_path, ledger_path = (
+        renewal["owner_config"], renewal["policy_path"], renewal["ledger_path"])
+    old_id = renewal["old_policy"].envelope_id
+    retired = renewal["retired_ledger"]
+    backups = [path.with_name(f"{path.name}.{old_id}.bak") for path in (owner_config, policy_path)]
+    if retired.exists() or any(path.exists() for path in backups):
+        raise RenewalRefused("a previous renewal from this envelope left files behind")
+    _ledger_settled(ledger_path)
+
+    staged = ledger_path.with_name(f".{ledger_path.name}.renew")
+    if staged.exists():
+        raise RenewalRefused("a staged ledger already exists")
+    new_ledger = SpendLedger(staged, renewal["new_policy"])
+    new_ledger.initialize()
+    RequestLedger(new_ledger).initialize()
+
+    for source, backup in zip((owner_config, policy_path), backups):
+        _write_private(backup, source.read_text())
+    os.rename(ledger_path, retired)
+    os.rename(staged, ledger_path)
+    _write_private(policy_path, json.dumps(renewal["new_policy"].__dict__, indent=2) + "\n")
+    _write_private(owner_config, json.dumps(renewal["new_owner"], indent=2) + "\n")
+    return {
+        "applied": True,
+        "catalog_file_pins": {str(path): _file_sha256(path) for path in (owner_config, policy_path)},
+        "next": "update the Secrets Engine exec_owner file pins, then run "
+                "metered-once --rehearse",
+    }
diff --git a/tests/test_owner_renew.py b/tests/test_owner_renew.py
new file mode 100644
index 0000000..45b6b81
--- /dev/null
+++ b/tests/test_owner_renew.py
@@ -0,0 +1,118 @@
+"""One-command owner renewal (REINAH-WP-0008-T03)."""
+
+from __future__ import annotations
+
+import hashlib
+import json
+import sqlite3
+from pathlib import Path
+
+import pytest
+
+from rein_aharness.cli import main
+from rein_aharness.owner_bootstrap import prepare
+from rein_aharness.owner_renew import RenewalRefused, apply, plan
+from rein_aharness.spend_admission import SpendLedger, SpendPolicy
+from test_owner_bootstrap import prepared as prepared
+from test_spend_admission import NOW, ledger as ledger, run
+
+ENVELOPE = {
+    "envelope_id": "renewed-2026-10-13",
+    "authority_ref": "fixture:owner-renewal",
+    "total_eur": "30",
+}
+
+
+def _paths(prepared, tmp_path, envelope=ENVELOPE):
+    path, config, _, runtime = prepared
+    envelope_path = tmp_path / "envelope.json"
+    envelope_path.write_text(json.dumps(envelope))
+    return (path, Path(config.spend_policy_path), Path(config.spend_ledger_path),
+            runtime, envelope_path)
+
+
+def _digests(*paths):
+    return {p: hashlib.sha256(p.read_bytes()).hexdigest() for p in paths}
+
+
+def test_dry_run_changes_nothing(prepared, tmp_path, capsys):
+    paths = _paths(prepared, tmp_path)
+    before = _digests(*paths[:3])
+    argv = ["owner", "renew", "--owner-config", str(paths[0]), "--policy", str(paths[1]),
+            "--ledger", str(paths[2]), "--runtime-path", str(paths[3]),
+            "--envelope", str(paths[4])]
+    assert main(argv) == 0
+    out = json.loads(capsys.readouterr().out)
+    assert out["dry_run"] is True and "catalog_file_pins" not in out
+    assert out["envelope"] == {"from": "test-only", "to": "renewed-2026-10-13"}
+    assert out["limits"]["total_eur"] == "30"
+    assert _digests(*paths[:3]) == before
+
+
+def test_apply_renews_and_owner_check_passes(prepared, tmp_path):
+    path, config, _, runtime = prepared
+    paths = _paths(prepared, tmp_path)
+    old_ledger = SpendLedger(paths[2], SpendPolicy.load(paths[1]))
+    result = apply(plan(*paths))
+
+    new_policy = SpendPolicy.load(paths[1])
+    owner = json.loads(paths[0].read_text())
+    assert new_policy.envelope_id == "renewed-2026-10-13" and new_policy.total_eur == "30"
+    assert owner["spend_policy_sha256"] == new_policy.sha256
+    assert owner["authority_ref"] == "fixture:owner-renewal"
+    assert owner["runtime"]["path"] == str(runtime)
+    # The real owner check accepts the renewed files at the unchanged paths.
+    prepare(path, config)
+    # Fresh ledger for the new envelope; the old one is retired, not reset.
+    assert SpendLedger(paths[2], new_policy).status()["reservations"] == []
+    retired = paths[2].with_name(f"{paths[2].name}.retired-test-only")
+    assert retired.exists()
+    assert paths[0].with_name("owner.json.test-only.bak").exists()
+    assert result["catalog_file_pins"] == {
+        str(p): d for p, d in _digests(paths[0], paths[1]).items()}
+    assert oct(paths[1].stat().st_mode & 0o777) == "0o600"
+
+
+def test_held_reservation_refuses(prepared, tmp_path):
+    paths = _paths(prepared, tmp_path)
+    db = sqlite3.connect(paths[2])
+    db.execute("INSERT INTO reservations (run_id, definition_id, idempotency_key, attempt, state, "
+               "liability, start_day) VALUES ('r', 'd', 'k', 1, 'held', 1, '2026-10-13')")
+    db.commit(); db.close()
+    with pytest.raises(RenewalRefused, match="held reservation"):
+        plan(*paths)
+
+
+@pytest.mark.parametrize("envelope,match", [
+    ({"total_eur": "30"}, "new envelope_id"),
+    ({**ENVELOPE, "envelope_id": "test-only"}, "new envelope_id"),
+    ({**ENVELOPE, "worker_id": "other"}, "envelope may only set"),
+    ({**ENVELOPE, "total_eur": "1"}, "new spend policy invalid"),
+])
+def test_bad_envelope_refuses(prepared, tmp_path, envelope, match):
+    with pytest.raises(RenewalRefused, match=match):
+        plan(*_paths(prepared, tmp_path, envelope))
+
+
+def test_second_apply_from_same_envelope_refuses(prepared, tmp_path):
+    paths = _paths(prepared, tmp_path)
+    renewal = plan(*paths)
+    apply(renewal)
+    with pytest.raises(RenewalRefused):
+        apply(renewal)
+
+
+def test_charged_reservation_renews_and_survives_in_retired_ledger(prepared, tmp_path):
+    # The railiance01 state after the 2026-10-13 reconciliation.
+    paths = _paths(prepared, tmp_path)
+    db = sqlite3.connect(paths[2])
+    db.execute("INSERT INTO reservations (run_id, definition_id, idempotency_key, attempt, state, "
+               "liability, start_day, end_day, observed_usd, receipt) VALUES ('6efa9436', 'd', 'k', "
+               "1, 'charged', 10000000, '2026-09-27', '2026-10-13', '0.05', 'owner-estimate')")
+    db.commit(); db.close()
+    apply(plan(*paths))
+    retired = sqlite3.connect(paths[2].with_name(f"{paths[2].name}.retired-test-only"))
+    assert retired.execute("SELECT state, liability FROM reservations").fetchall() == [
+        ("charged", 10000000)]
+    retired.close()
+    assert SpendLedger(paths[2], SpendPolicy.load(paths[1])).status()["reservations"] == []
diff --git a/workplans/REINAH-WP-0008-simpler-metered-retry.md b/workplans/REINAH-WP-0008-simpler-metered-retry.md
index 633f080..f2cafa1 100644
--- a/workplans/REINAH-WP-0008-simpler-metered-retry.md
+++ b/workplans/REINAH-WP-0008-simpler-metered-retry.md
@@ -117,7 +117,7 @@ release.
 
 ```task
 id: REINAH-WP-0008-T03
-status: todo
+status: done
 priority: high
 state_hub_task_id: "87457216-2371-51ca-b3d4-3917e6f180a2"
 ```
@@ -139,6 +139,36 @@ rehearsal.
 The owner check passes on the result. A second renew with an unsettled
 reservation refuses. No digest has to be typed by hand.
 
+### Implemented — 2026-10-13
+
+The command is `rein-aharness owner renew --owner-config --policy --ledger
+--runtime-path --envelope [--apply]`, in `rein_aharness/owner_renew.py`.
+Without `--apply` it is a dry run. Choices:
+
+- **Envelope file:** only the envelope fields may change. Worker, target,
+  profile and grant pins carry over, and `SpendPolicy` validation runs on
+  the result.
+- **Paths stay the same:** the old ledger is renamed to
+  `.retired-<old envelope>`, never reset, and the old policy and owner.json
+  are kept as `.bak`. Secrets Engine pins the `exec_owner` files by sha256
+  and the ledger path through its fixed environment, so keeping the paths
+  means the catalog needs only new file hashes. The command prints them.
+- **Refusals:** a held reservation, an open request route, an open SQLite
+  transaction, an owner.json that doesn't match the policy, a reused
+  envelope id, a disallowed field, or leftovers from an earlier renewal.
+
+Tests (`tests/test_owner_renew.py`):
+
+- A dry run changes nothing.
+- An applied renewal passes the real owner check (`prepare`) at the
+  unchanged paths.
+- A charged reservation, the railiance01 state after the 2026-10-13
+  reconciliation, renews, and the row survives in the retired ledger.
+- Bad envelopes and a second apply both refuse.
+
+Finding for T06: renewal still changes the pinned file hashes, so each
+renewal needs a Secrets Engine catalog update and fresh approvals.
+
 ## C. Envelopes that cover several attempts (decision)
 
 ```task