feat(control-plane): add governed host seed executor

active-runtime/app/aios_control_plane_host_seed_executor.py

@@ -0,0 +1,748 @@
+#!/usr/bin/env python3
+"""Server-local governed immutable Host seed executor.
+
+This executor is deliberately not a general-purpose privileged command runner.
+It polls one fixed Git ref/path, verifies a high-risk governed-task binding as
+the durable authorization evidence, materializes one exact candidate from the
+authoritative Git object database plus a declared patch/manifest, and atomically
+publishes the immutable release tree.
+
+It never starts/restarts services, never creates the continuation Task/Job,
+never writes Git refs, and never switches Production.
+"""
+from __future__ import annotations
+
+from dataclasses import dataclass
+from datetime import datetime, timezone
+import argparse
+import fcntl
+import hashlib
+import json
+import os
+import pwd
+from pathlib import Path, PurePosixPath
+import re
+import shutil
+import stat
+import subprocess
+import tempfile
+from typing import Any, Mapping
+
+REQUEST_SCHEMA = "aios.control-plane-host-seed-request.v1"
+MANIFEST_SCHEMAS = {
+    "aios.control-plane-immutable-candidate.v5",
+    "aios.control-plane-immutable-candidate.v6",
+}
+OPERATION = "HOST_SEED_IMMUTABLE_CANDIDATE"
+REPOSITORY = "aios/aios"
+REQUEST_REF = "refs/heads/agent/host-seed-authorization-requests"
+REQUEST_PATH = "control-plane/host-seed/request.json"
+OID_RE = re.compile(r"^[0-9a-f]{40}$")
+SHA_RE = re.compile(r"^[0-9a-f]{64}$")
+TASK_RE = re.compile(r"^[A-Za-z0-9][A-Za-z0-9._:-]{2,179}$")
+RELEASE_RE = re.compile(r"^[A-Za-z0-9][A-Za-z0-9._-]{3,191}$")
+CANDIDATE_RE = re.compile(r"^V[0-9]+$")
+MAX_REQUEST_BYTES = 128 * 1024
+MAX_MANIFEST_BYTES = 4 * 1024 * 1024
+MAX_PATCH_BYTES = 2 * 1024 * 1024
+MAX_MACHINE_GOAL_BYTES = 512 * 1024
+MAX_BOOTSTRAP_BYTES = 512 * 1024
+
+
+class HostSeedError(RuntimeError):
+    pass
+
+
+def canonical(value: object) -> bytes:
+    return (json.dumps(value, ensure_ascii=False, sort_keys=True, separators=(",", ":")) + "\n").encode("utf-8")
+
+
+def sha256(data: bytes) -> str:
+    return hashlib.sha256(data).hexdigest()
+
+
+def canonical_compact(value: object) -> bytes:
+    return json.dumps(
+        value, ensure_ascii=False, sort_keys=True, separators=(",", ":")
+    ).encode("utf-8")
+
+
+def _git(git_dir: Path, *args: str, input_bytes: bytes | None = None) -> bytes:
+    env = {"PATH": os.environ.get("PATH", "")}
+    proc = subprocess.run(
+        ["git", f"--git-dir={git_dir}", *args],
+        input=input_bytes,
+        capture_output=True,
+        timeout=120,
+        env=env,
+    )
+    if proc.returncode:
+        raise HostSeedError("GIT_" + (args[0] if args else "COMMAND").upper() + "_FAILED")
+    return proc.stdout
+
+
+def _git_text(git_dir: Path, *args: str) -> str:
+    return _git(git_dir, *args).decode("utf-8", "strict").strip()
+
+
+def _safe_repo_path(value: object, *, field: str) -> str:
+    if not isinstance(value, str) or not value or len(value) > 512:
+        raise HostSeedError(field + "_INVALID")
+    p = PurePosixPath(value)
+    if p.is_absolute() or any(part in {"", ".", ".."} for part in p.parts):
+        raise HostSeedError(field + "_INVALID")
+    normalized = p.as_posix()
+    if normalized.startswith(".git/") or normalized == ".git":
+        raise HostSeedError(field + "_INVALID")
+    return normalized
+
+
+def _read_git_blob(git_dir: Path, oid: str, path: str, *, maximum: int) -> bytes:
+    if not OID_RE.fullmatch(oid):
+        raise HostSeedError("PAYLOAD_COMMIT_INVALID")
+    raw = _git(git_dir, "show", f"{oid}:{path}")
+    if len(raw) <= 0 or len(raw) > maximum:
+        raise HostSeedError("GIT_BLOB_SIZE_INVALID")
+    return raw
+
+
+def _parse_json(raw: bytes, *, code: str) -> dict[str, Any]:
+    try:
+        value = json.loads(raw.decode("utf-8"))
+    except (UnicodeDecodeError, json.JSONDecodeError) as exc:
+        raise HostSeedError(code) from exc
+    if not isinstance(value, dict):
+        raise HostSeedError(code)
+    return value
+
+
+def _parse_time(value: object, *, field: str) -> datetime:
+    if not isinstance(value, str) or not value:
+        raise HostSeedError(field + "_INVALID")
+    text = value[:-1] + "+00:00" if value.endswith("Z") else value
+    try:
+        parsed = datetime.fromisoformat(text)
+    except ValueError as exc:
+        raise HostSeedError(field + "_INVALID") from exc
+    if parsed.tzinfo is None:
+        raise HostSeedError(field + "_INVALID")
+    return parsed.astimezone(timezone.utc)
+
+
+def _regular_file_bytes(
+    path: Path, *, maximum: int, expected_uid: int | None = None
+) -> bytes:
+    if path.parent.is_symlink():
+        raise HostSeedError("AUTHORIZATION_BINDING_PARENT_SYMLINK_REJECTED")
+    flags = os.O_RDONLY | getattr(os, "O_CLOEXEC", 0) | getattr(os, "O_NOFOLLOW", 0)
+    try:
+        fd = os.open(path, flags)
+    except OSError as exc:
+        raise HostSeedError("AUTHORIZATION_BINDING_UNAVAILABLE") from exc
+    try:
+        info = os.fstat(fd)
+        if not stat.S_ISREG(info.st_mode) or info.st_size <= 0 or info.st_size > maximum:
+            raise HostSeedError("AUTHORIZATION_BINDING_INVALID")
+        if info.st_mode & 0o022:
+            raise HostSeedError("AUTHORIZATION_BINDING_WRITABLE_BY_GROUP_OR_OTHER")
+        if expected_uid is not None and info.st_uid != expected_uid:
+            raise HostSeedError("AUTHORIZATION_BINDING_OWNER_MISMATCH")
+        raw = os.read(fd, maximum + 1)
+        if len(raw) > maximum:
+            raise HostSeedError("AUTHORIZATION_BINDING_INVALID")
+        return raw
+    finally:
+        os.close(fd)
+
+
+def _atomic_json(path: Path, value: Mapping[str, Any], *, mode: int = 0o600) -> None:
+    path.parent.mkdir(parents=True, exist_ok=True, mode=0o700)
+    if path.parent.is_symlink() or path.is_symlink():
+        raise HostSeedError("STATE_SYMLINK_REJECTED")
+    fd, temporary = tempfile.mkstemp(prefix=".tmp-", dir=path.parent)
+    try:
+        os.fchmod(fd, mode)
+        with os.fdopen(fd, "wb", closefd=True) as stream:
+            stream.write(canonical(value))
+            stream.flush()
+            os.fsync(stream.fileno())
+        os.replace(temporary, path)
+        os.chmod(path, mode)
+        parent_fd = os.open(path.parent, os.O_RDONLY | getattr(os, "O_DIRECTORY", 0))
+        try:
+            os.fsync(parent_fd)
+        finally:
+            os.close(parent_fd)
+    finally:
+        if os.path.exists(temporary):
+            os.unlink(temporary)
+
+
+@dataclass(frozen=True)
+class Intent:
+    candidate: str
+    release_id: str
+    base_oid: str
+    payload_commit: str
+    patch_path: str
+    manifest_path: str
+    machine_goal_path: str
+    seed_bootstrap_path: str
+    artifact_sha256: str
+    manifest_sha256: str
+    machine_goal_sha256: str
+    release_tree_sha256: str
+    seed_bootstrap_sha256: str
+    target_host: str
+
+    def as_dict(self) -> dict[str, Any]:
+        return {
+            "candidate": self.candidate,
+            "release_id": self.release_id,
+            "base_oid": self.base_oid,
+            "payload_commit": self.payload_commit,
+            "patch_path": self.patch_path,
+            "manifest_path": self.manifest_path,
+            "machine_goal_path": self.machine_goal_path,
+            "seed_bootstrap_path": self.seed_bootstrap_path,
+            "artifact_sha256": self.artifact_sha256,
+            "manifest_sha256": self.manifest_sha256,
+            "machine_goal_sha256": self.machine_goal_sha256,
+            "release_tree_sha256": self.release_tree_sha256,
+            "seed_bootstrap_sha256": self.seed_bootstrap_sha256,
+            "target_host": self.target_host,
+        }
+
+    @property
+    def digest(self) -> str:
+        return sha256(canonical(self.as_dict()))
+
+
+@dataclass(frozen=True)
+class Request:
+    intent: Intent
+    authorization_task_id: str
+    authorization_binding_sha256: str
+    authorization_sha256: str
+    expires_at: datetime
+
+    @classmethod
+    def load(cls, raw: Mapping[str, Any], *, host_identity: str, now: datetime) -> "Request":
+        if set(raw) != {"schema", "operation", "repository", "intent", "authorization"}:
+            raise HostSeedError("REQUEST_FIELDS_INVALID")
+        if raw.get("schema") != REQUEST_SCHEMA or raw.get("operation") != OPERATION:
+            raise HostSeedError("REQUEST_CONTRACT_INVALID")
+        if raw.get("repository") != REPOSITORY:
+            raise HostSeedError("REQUEST_REPOSITORY_MISMATCH")
+        intent_raw = raw.get("intent")
+        if not isinstance(intent_raw, Mapping) or set(intent_raw) != {
+            "candidate", "release_id", "base_oid", "payload_commit", "patch_path",
+            "manifest_path", "machine_goal_path", "seed_bootstrap_path",
+            "artifact_sha256", "manifest_sha256", "machine_goal_sha256",
+            "release_tree_sha256", "seed_bootstrap_sha256", "target_host",
+        }:
+            raise HostSeedError("INTENT_FIELDS_INVALID")
+        candidate = str(intent_raw.get("candidate") or "")
+        release_id = str(intent_raw.get("release_id") or "")
+        base_oid = str(intent_raw.get("base_oid") or "")
+        payload_commit = str(intent_raw.get("payload_commit") or "")
+        artifact_sha = str(intent_raw.get("artifact_sha256") or "")
+        manifest_sha = str(intent_raw.get("manifest_sha256") or "")
+        machine_goal_sha = str(intent_raw.get("machine_goal_sha256") or "")
+        release_tree_sha = str(intent_raw.get("release_tree_sha256") or "")
+        seed_bootstrap_sha = str(intent_raw.get("seed_bootstrap_sha256") or "")
+        target_host = str(intent_raw.get("target_host") or "")
+        if not CANDIDATE_RE.fullmatch(candidate):
+            raise HostSeedError("CANDIDATE_INVALID")
+        if not RELEASE_RE.fullmatch(release_id):
+            raise HostSeedError("RELEASE_ID_INVALID")
+        if not OID_RE.fullmatch(base_oid) or not OID_RE.fullmatch(payload_commit):
+            raise HostSeedError("INTENT_OID_INVALID")
+        if not all(SHA_RE.fullmatch(x) for x in (
+            artifact_sha, manifest_sha, machine_goal_sha, release_tree_sha, seed_bootstrap_sha
+        )):
+            raise HostSeedError("INTENT_SHA_INVALID")
+        if target_host != host_identity:
+            raise HostSeedError("TARGET_HOST_MISMATCH")
+        intent = Intent(
+            candidate=candidate,
+            release_id=release_id,
+            base_oid=base_oid,
+            payload_commit=payload_commit,
+            patch_path=_safe_repo_path(intent_raw.get("patch_path"), field="PATCH_PATH"),
+            manifest_path=_safe_repo_path(intent_raw.get("manifest_path"), field="MANIFEST_PATH"),
+            machine_goal_path=_safe_repo_path(intent_raw.get("machine_goal_path"), field="MACHINE_GOAL_PATH"),
+            seed_bootstrap_path=_safe_repo_path(intent_raw.get("seed_bootstrap_path"), field="SEED_BOOTSTRAP_PATH"),
+            artifact_sha256=artifact_sha,
+            manifest_sha256=manifest_sha,
+            machine_goal_sha256=machine_goal_sha,
+            release_tree_sha256=release_tree_sha,
+            seed_bootstrap_sha256=seed_bootstrap_sha,
+            target_host=target_host,
+        )
+        auth = raw.get("authorization")
+        if not isinstance(auth, Mapping) or set(auth) != {
+            "task_id", "binding_sha256", "expires_at", "intent_sha256",
+            "authorization_sha256",
+        }:
+            raise HostSeedError("AUTHORIZATION_FIELDS_INVALID")
+        task_id = str(auth.get("task_id") or "")
+        binding_sha = str(auth.get("binding_sha256") or "")
+        authorization_sha = str(auth.get("authorization_sha256") or "")
+        if (
+            not TASK_RE.fullmatch(task_id)
+            or not SHA_RE.fullmatch(binding_sha)
+            or not SHA_RE.fullmatch(authorization_sha)
+        ):
+            raise HostSeedError("AUTHORIZATION_IDENTITY_INVALID")
+        if auth.get("intent_sha256") != intent.digest:
+            raise HostSeedError("AUTHORIZATION_INTENT_MISMATCH")
+        expires_text = str(auth.get("expires_at") or "")
+        expires_at = _parse_time(expires_text, field="AUTHORIZATION_EXPIRES_AT")
+        expected_authorization_sha = sha256(canonical({
+            "task_id": task_id,
+            "intent_sha256": intent.digest,
+            "expires_at": expires_text,
+        }))
+        if authorization_sha != expected_authorization_sha:
+            raise HostSeedError("AUTHORIZATION_DIGEST_MISMATCH")
+        if now >= expires_at:
+            raise HostSeedError("AUTHORIZATION_EXPIRED")
+        if (expires_at - now).total_seconds() > 3600:
+            raise HostSeedError("AUTHORIZATION_WINDOW_TOO_LARGE")
+        return cls(
+            intent=intent,
+            authorization_task_id=task_id,
+            authorization_binding_sha256=binding_sha,
+            authorization_sha256=authorization_sha,
+            expires_at=expires_at,
+        )
+
+
+@dataclass(frozen=True)
+class Config:
+    git_dir: Path
+    task_binding_root: Path
+    state_root: Path
+    release_root: Path
+    host_identity: str
+    task_binding_owner: str | None = "aios-bridge-staging"
+    request_ref: str = REQUEST_REF
+    request_path: str = REQUEST_PATH
+
+
+def _load_task_binding(config: Config, request: Request) -> dict[str, Any]:
+    safe = re.sub(r"[^A-Za-z0-9_.-]+", "-", request.authorization_task_id).strip("-")[:120] or "task"
+    path = config.task_binding_root / f"{safe}.json"
+    expected_uid = None
+    if config.task_binding_owner:
+        try:
+            expected_uid = pwd.getpwnam(config.task_binding_owner).pw_uid
+        except KeyError as exc:
+            raise HostSeedError("AUTHORIZATION_BINDING_OWNER_UNKNOWN") from exc
+    raw = _regular_file_bytes(path, maximum=256 * 1024, expected_uid=expected_uid)
+    if sha256(raw) != request.authorization_binding_sha256:
+        raise HostSeedError("AUTHORIZATION_BINDING_HASH_MISMATCH")
+    binding = _parse_json(raw, code="AUTHORIZATION_BINDING_JSON_INVALID")
+    required = {
+        "task_id", "repository", "base_oid", "target_branch", "risk",
+        "description", "idempotency_key", "expected_branch_oid",
+        "branch_mode", "generation", "job_id",
+    }
+    if set(binding) != required:
+        raise HostSeedError("AUTHORIZATION_BINDING_FIELDS_INVALID")
+    if binding.get("task_id") != request.authorization_task_id:
+        raise HostSeedError("AUTHORIZATION_TASK_MISMATCH")
+    if binding.get("repository") != REPOSITORY:
+        raise HostSeedError("AUTHORIZATION_REPOSITORY_MISMATCH")
+    if binding.get("risk") != "high":
+        raise HostSeedError("AUTHORIZATION_RISK_MISMATCH")
+    if binding.get("description") != "HOST_SEED_AUTHORIZATION:" + request.authorization_sha256:
+        raise HostSeedError("AUTHORIZATION_DESCRIPTION_MISMATCH")
+    if not str(binding.get("target_branch") or "").startswith("agent/host-seed-authorization-"):
+        raise HostSeedError("AUTHORIZATION_BRANCH_MISMATCH")
+    if not isinstance(binding.get("generation"), int) or binding["generation"] < 1:
+        raise HostSeedError("AUTHORIZATION_GENERATION_INVALID")
+    return binding
+
+
+def _load_manifest(config: Config, request: Request) -> dict[str, Any]:
+    raw = _read_git_blob(
+        config.git_dir, request.intent.payload_commit, request.intent.manifest_path,
+        maximum=MAX_MANIFEST_BYTES,
+    )
+    if sha256(raw) != request.intent.manifest_sha256:
+        raise HostSeedError("MANIFEST_HASH_MISMATCH")
+    manifest = _parse_json(raw, code="MANIFEST_JSON_INVALID")
+    if manifest.get("schema") not in MANIFEST_SCHEMAS:
+        raise HostSeedError("MANIFEST_SCHEMA_REJECTED")
+    if manifest.get("candidate") != request.intent.candidate:
+        raise HostSeedError("MANIFEST_CANDIDATE_MISMATCH")
+    if manifest.get("repository") != REPOSITORY:
+        raise HostSeedError("MANIFEST_REPOSITORY_MISMATCH")
+    if manifest.get("base_oid") != request.intent.base_oid:
+        raise HostSeedError("MANIFEST_BASE_MISMATCH")
+    if manifest.get("release_id") != request.intent.release_id:
+        raise HostSeedError("MANIFEST_RELEASE_ID_MISMATCH")
+    members = manifest.get("package_members")
+    changes = manifest.get("changed_files")
+    if not isinstance(members, Mapping) or not isinstance(changes, list):
+        raise HostSeedError("MANIFEST_MEMBERS_INVALID")
+    return manifest
+
+
+def _load_identity_evidence(config: Config, request: Request) -> dict[str, Any]:
+    goal_raw = _read_git_blob(
+        config.git_dir, request.intent.payload_commit, request.intent.machine_goal_path,
+        maximum=MAX_MACHINE_GOAL_BYTES,
+    )
+    if sha256(goal_raw) != request.intent.machine_goal_sha256:
+        raise HostSeedError("MACHINE_GOAL_HASH_MISMATCH")
+    goal = _parse_json(goal_raw, code="MACHINE_GOAL_JSON_INVALID")
+    required_pairs = {
+        "candidate": request.intent.candidate,
+        "repository": REPOSITORY,
+        "base_oid": request.intent.base_oid,
+        "release_id": request.intent.release_id,
+        "artifact_sha256": request.intent.artifact_sha256,
+        "manifest_sha256": request.intent.manifest_sha256,
+        "release_tree_sha256": request.intent.release_tree_sha256,
+        "seed_bootstrap_sha256": request.intent.seed_bootstrap_sha256,
+    }
+    for key, expected in required_pairs.items():
+        if goal.get(key) != expected:
+            raise HostSeedError("MACHINE_GOAL_BINDING_MISMATCH:" + key)
+    if goal.get("host_seed_authorized") is not False:
+        raise HostSeedError("MACHINE_GOAL_HOST_SEED_FLAG_INVALID")
+    bootstrap = _read_git_blob(
+        config.git_dir, request.intent.payload_commit, request.intent.seed_bootstrap_path,
+        maximum=MAX_BOOTSTRAP_BYTES,
+    )
+    if sha256(bootstrap) != request.intent.seed_bootstrap_sha256:
+        raise HostSeedError("SEED_BOOTSTRAP_HASH_MISMATCH")
+    return goal
+
+
+def _load_patch(config: Config, request: Request) -> bytes:
+    patch = _read_git_blob(
+        config.git_dir, request.intent.payload_commit, request.intent.patch_path,
+        maximum=MAX_PATCH_BYTES,
+    )
+    if b"\x00" in patch:
+        raise HostSeedError("PATCH_BINARY_NUL_REJECTED")
+    return patch
+
+
+def _manifest_release_map(manifest: Mapping[str, Any]) -> dict[str, str]:
+    members = manifest["package_members"]
+    result: dict[str, str] = {}
+    prefix = "payload/repo/after/"
+    for name, digest in members.items():
+        if not isinstance(name, str) or not name.startswith(prefix) or not isinstance(digest, str) or not SHA_RE.fullmatch(digest):
+            continue
+        rel = _safe_repo_path(name[len(prefix):], field="RELEASE_MEMBER")
+        if rel in result:
+            raise HostSeedError("DUPLICATE_RELEASE_MEMBER")
+        result[rel] = digest
+    declared_count = manifest.get("release_member_count")
+    if not isinstance(declared_count, int) or declared_count != len(result):
+        raise HostSeedError("RELEASE_MEMBER_COUNT_MISMATCH")
+    return result
+
+
+def _expected_changes(manifest: Mapping[str, Any]) -> dict[str, tuple[str, str]]:
+    result: dict[str, tuple[str, str]] = {}
+    for entry in manifest["changed_files"]:
+        if not isinstance(entry, Mapping):
+            raise HostSeedError("CHANGED_FILE_ENTRY_INVALID")
+        rel = _safe_repo_path(entry.get("path"), field="CHANGED_PATH")
+        digest = str(entry.get("after_sha256") or "")
+        status = str(entry.get("status") or "")
+        if not SHA_RE.fullmatch(digest) or status not in {"modified", "added"} or rel in result:
+            raise HostSeedError("CHANGED_FILE_ENTRY_INVALID")
+        result[rel] = (digest, status)
+    if manifest.get("changed_file_count") != len(result):
+        raise HostSeedError("CHANGED_FILE_COUNT_MISMATCH")
+    return result
+
+
+def _regular_member(root: Path, relative: str) -> Path:
+    current = root
+    for part in PurePosixPath(relative).parts:
+        current = current / part
+        try:
+            info = current.lstat()
+        except FileNotFoundError as exc:
+            raise HostSeedError("RELEASE_MEMBER_MISSING:" + relative) from exc
+        if stat.S_ISLNK(info.st_mode):
+            raise HostSeedError("RELEASE_MEMBER_SYMLINK_REJECTED:" + relative)
+    if not current.is_file():
+        raise HostSeedError("RELEASE_MEMBER_NOT_REGULAR:" + relative)
+    return current
+
+
+def _materialize_and_verify(config: Config, request: Request, manifest: Mapping[str, Any], patch: bytes, workspace: Path) -> dict[str, str]:
+    if _git_text(config.git_dir, "cat-file", "-t", request.intent.base_oid) != "commit":
+        raise HostSeedError("BASE_COMMIT_NOT_FOUND")
+    if _git_text(config.git_dir, "cat-file", "-t", request.intent.payload_commit) != "commit":
+        raise HostSeedError("PAYLOAD_COMMIT_NOT_FOUND")
+    workspace.parent.mkdir(parents=True, exist_ok=True)
+    clone = subprocess.run(
+        ["git", "clone", "--no-checkout", "--shared", str(config.git_dir), str(workspace)],
+        capture_output=True, timeout=120, env={"PATH": os.environ.get("PATH", "")},
+    )
+    if clone.returncode:
+        raise HostSeedError("WORKSPACE_CLONE_FAILED")
+    checkout = subprocess.run(
+        ["git", "-C", str(workspace), "checkout", "--detach", request.intent.base_oid],
+        capture_output=True, timeout=120, env={"PATH": os.environ.get("PATH", "")},
+    )
+    if checkout.returncode:
+        raise HostSeedError("WORKSPACE_CHECKOUT_FAILED")
+    try:
+        proc = subprocess.run(
+            ["git", "-C", str(workspace), "apply", "--whitespace=nowarn", "-"],
+            input=patch, capture_output=True, timeout=120, env={"PATH": os.environ.get("PATH", "")},
+        )
+        if proc.returncode:
+            raise HostSeedError("PATCH_APPLY_FAILED")
+        changes = _expected_changes(manifest)
+        status_raw = subprocess.run(
+            ["git", "-C", str(workspace), "status", "--porcelain", "-z"],
+            check=True, capture_output=True, timeout=120, env={"PATH": os.environ.get("PATH", "")},
+        ).stdout
+        actual: set[str] = set()
+        chunks = status_raw.split(b"\0")
+        for chunk in chunks:
+            if not chunk:
+                continue
+            text = chunk.decode("utf-8", "surrogateescape")
+            if len(text) < 4:
+                raise HostSeedError("WORKTREE_STATUS_INVALID")
+            actual.add(text[3:].replace("\\", "/"))
+        if actual != set(changes):
+            raise HostSeedError("PATCH_CHANGESET_MISMATCH")
+        base_paths = {
+            _safe_repo_path(path, field="TRACKED_PATH")
+            for path in _git_text(config.git_dir, "ls-tree", "-r", "--name-only", request.intent.base_oid).splitlines()
+            if path
+        }
+        for rel, (digest, status) in changes.items():
+            if status == "modified" and rel not in base_paths:
+                raise HostSeedError("MODIFIED_PATH_NOT_IN_BASE:" + rel)
+            if status == "added" and rel in base_paths:
+                raise HostSeedError("ADDED_PATH_ALREADY_IN_BASE:" + rel)
+            p = _regular_member(workspace, rel)
+            if sha256(p.read_bytes()) != digest:
+                raise HostSeedError("CHANGED_FILE_HASH_MISMATCH:" + rel)
+        release_map = _manifest_release_map(manifest)
+        expected_release_paths = base_paths | {
+            rel for rel, (_digest, status) in changes.items() if status == "added"
+        }
+        if set(release_map) != expected_release_paths:
+            raise HostSeedError("RELEASE_MEMBER_SET_MISMATCH")
+        for rel, digest in release_map.items():
+            p = _regular_member(workspace, rel)
+            if sha256(p.read_bytes()) != digest:
+                raise HostSeedError("RELEASE_MEMBER_HASH_MISMATCH:" + rel)
+        tree_digest = sha256(canonical_compact({f"payload/repo/after/{k}": release_map[k] for k in sorted(release_map)}))
+        if tree_digest != request.intent.release_tree_sha256:
+            raise HostSeedError("RELEASE_TREE_HASH_MISMATCH")
+        if manifest.get("release_tree_sha256") not in {None, request.intent.release_tree_sha256}:
+            raise HostSeedError("MANIFEST_RELEASE_TREE_HASH_MISMATCH")
+        return release_map
+    except Exception:
+        raise
+
+
+def _publish_release(config: Config, request: Request, workspace: Path, release_map: Mapping[str, str]) -> Path:
+    if config.release_root.exists() and config.release_root.is_symlink():
+        raise HostSeedError("RELEASE_ROOT_SYMLINK_REJECTED")
+    final = config.release_root / request.intent.release_id
+    if final.exists():
+        if final.is_symlink() or not final.is_dir():
+            raise HostSeedError("RELEASE_DESTINATION_CONFLICT")
+        for rel, digest in release_map.items():
+            p = final / PurePosixPath(rel)
+            if p.is_symlink() or not p.is_file() or sha256(p.read_bytes()) != digest:
+                raise HostSeedError("EXISTING_RELEASE_HASH_MISMATCH")
+        return final
+
+    config.release_root.mkdir(parents=True, exist_ok=True)
+    os.chmod(config.release_root, 0o755)
+    staging = Path(tempfile.mkdtemp(prefix=".host-seed-", dir=config.release_root))
+    os.chmod(staging, 0o755)
+    try:
+        for rel, digest in release_map.items():
+            source = _regular_member(workspace, rel)
+            target = staging / PurePosixPath(rel)
+            target.parent.mkdir(parents=True, exist_ok=True)
+            current = target.parent
+            while current != staging:
+                os.chmod(current, 0o755)
+                current = current.parent
+            data = source.read_bytes()
+            if sha256(data) != digest:
+                raise HostSeedError("STAGING_SOURCE_DRIFT")
+            fd = os.open(target, os.O_WRONLY | os.O_CREAT | os.O_EXCL | getattr(os, "O_NOFOLLOW", 0), 0o600)
+            try:
+                with os.fdopen(fd, "wb", closefd=True) as out:
+                    out.write(data)
+                    out.flush()
+                    os.fsync(out.fileno())
+            except Exception:
+                raise
+            source_mode = stat.S_IMODE(source.stat(follow_symlinks=False).st_mode)
+            os.chmod(target, source_mode & 0o755 or 0o644)
+        for rel, digest in release_map.items():
+            p = staging / PurePosixPath(rel)
+            if p.is_symlink() or sha256(p.read_bytes()) != digest:
+                raise HostSeedError("STAGING_VERIFY_FAILED")
+        os.replace(staging, final)
+        parent_fd = os.open(config.release_root, os.O_RDONLY | getattr(os, "O_DIRECTORY", 0))
+        try:
+            os.fsync(parent_fd)
+        finally:
+            os.close(parent_fd)
+        return final
+    finally:
+        if staging.exists():
+            shutil.rmtree(staging)
+
+
+def execute(config: Config, *, now: datetime | None = None, require_root: bool = True) -> dict[str, Any]:
+    if require_root and os.geteuid() != 0:
+        raise HostSeedError("ROOT_REQUIRED")
+    current = now or datetime.now(timezone.utc)
+    config.state_root.mkdir(parents=True, exist_ok=True, mode=0o700)
+    lock_path = config.state_root / "executor.lock"
+    lock_fd = os.open(lock_path, os.O_RDWR | os.O_CREAT, 0o600)
+    try:
+        fcntl.flock(lock_fd, fcntl.LOCK_EX)
+        ref_probe = subprocess.run(
+            ["git", f"--git-dir={config.git_dir}", "rev-parse", "--verify", config.request_ref],
+            capture_output=True, timeout=30, env={"PATH": os.environ.get("PATH", "")},
+        )
+        if ref_probe.returncode:
+            return {
+                "schema": "aios.control-plane-host-seed-poll.v1",
+                "state": "NO_REQUEST",
+                "request_ref": config.request_ref,
+                "service_mutation": False,
+                "task_creation": False,
+            }
+        request_oid = ref_probe.stdout.decode("utf-8", "strict").strip()
+        if not OID_RE.fullmatch(request_oid):
+            raise HostSeedError("REQUEST_REF_INVALID")
+        raw = _read_git_blob(config.git_dir, request_oid, config.request_path, maximum=MAX_REQUEST_BYTES)
+        request_value = _parse_json(raw, code="REQUEST_JSON_INVALID")
+        request = Request.load(request_value, host_identity=config.host_identity, now=current)
+        binding = _load_task_binding(config, request)
+        manifest = _load_manifest(config, request)
+        _load_identity_evidence(config, request)
+        patch = _load_patch(config, request)
+
+        op_id = request.intent.digest
+        receipt_path = config.state_root / "receipts" / f"{op_id}.json"
+        if receipt_path.exists():
+            receipt = _parse_json(_regular_file_bytes(receipt_path, maximum=256 * 1024), code="RECEIPT_INVALID")
+            if receipt.get("state") == "EXECUTED" and receipt.get("intent_sha256") == op_id:
+                return receipt
+            raise HostSeedError("OPERATION_STATE_CONFLICT")
+
+        _atomic_json(config.state_root / "operations" / f"{op_id}.json", {
+            "schema": "aios.control-plane-host-seed-operation.v1",
+            "state": "PENDING",
+            "intent_sha256": op_id,
+            "request_commit": request_oid,
+            "authorization_task_id": request.authorization_task_id,
+            "authorization_binding_sha256": request.authorization_binding_sha256,
+            "started_at": current.isoformat().replace("+00:00", "Z"),
+        })
+
+        workspace_root = config.state_root / "workspaces"
+        workspace_root.mkdir(parents=True, exist_ok=True)
+        workspace = workspace_root / f"seed-{op_id[:20]}"
+        if workspace.exists():
+            raise HostSeedError("WORKSPACE_ALREADY_EXISTS")
+        release_map: dict[str, str] | None = None
+        try:
+            release_map = _materialize_and_verify(config, request, manifest, patch, workspace)
+            destination = _publish_release(config, request, workspace, release_map)
+        finally:
+            if workspace.exists():
+                shutil.rmtree(workspace, ignore_errors=True)
+
+        receipt = {
+            "schema": "aios.control-plane-host-seed-receipt.v1",
+            "state": "EXECUTED",
+            "operation": OPERATION,
+            "intent_sha256": op_id,
+            "request_commit": request_oid,
+            "repository": REPOSITORY,
+            "target_host": request.intent.target_host,
+            "candidate": request.intent.candidate,
+            "release_id": request.intent.release_id,
+            "base_oid": request.intent.base_oid,
+            "payload_commit": request.intent.payload_commit,
+            "validation_artifact_sha256": request.intent.artifact_sha256,
+            "artifact_delivery_used": False,
+            "manifest_sha256": request.intent.manifest_sha256,
+            "machine_goal_sha256": request.intent.machine_goal_sha256,
+            "release_tree_sha256": request.intent.release_tree_sha256,
+            "seed_bootstrap_sha256": request.intent.seed_bootstrap_sha256,
+            "authorization_task_id": request.authorization_task_id,
+            "authorization_binding_sha256": request.authorization_binding_sha256,
+            "release_path": str(destination),
+            "release_member_count": len(release_map or {}),
+            "service_mutation": False,
+            "service_restart": False,
+            "projector_started": False,
+            "task_creation": False,
+            "production_write": False,
+            "main_write": False,
+            "tag_write": False,
+            "baseline_write": False,
+            "executed_at": datetime.now(timezone.utc).isoformat().replace("+00:00", "Z"),
+        }
+        _atomic_json(receipt_path, receipt)
+        _atomic_json(config.state_root / "operations" / f"{op_id}.json", receipt)
+        return receipt
+    finally:
+        fcntl.flock(lock_fd, fcntl.LOCK_UN)
+        os.close(lock_fd)
+
+
+def config_from_environment() -> Config:
+    return Config(
+        git_dir=Path(os.environ.get("AIOS_HOST_SEED_GIT_DIR", "/data/aios-gitops/repo.git")),
+        task_binding_root=Path(os.environ.get(
+            "AIOS_HOST_SEED_TASK_BINDING_ROOT",
+            "/var/lib/aios-gitops/bridge-v2-staging/task-bindings",
+        )),
+        state_root=Path(os.environ.get(
+            "AIOS_HOST_SEED_STATE_ROOT",
+            "/var/lib/aios-control-plane-host-seed-executor",
+        )),
+        release_root=Path(os.environ.get("AIOS_HOST_SEED_RELEASE_ROOT", "/opt/aios/releases")),
+        host_identity=os.environ.get("AIOS_HOST_IDENTITY", "cn-network-mkt"),
+        task_binding_owner=os.environ.get(
+            "AIOS_HOST_SEED_TASK_BINDING_OWNER", "aios-bridge-staging"
+        ) or None,
+        request_ref=os.environ.get("AIOS_HOST_SEED_REQUEST_REF", REQUEST_REF),
+        request_path=os.environ.get("AIOS_HOST_SEED_REQUEST_PATH", REQUEST_PATH),
+    )
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("command", choices=("execute",))
+    args = parser.parse_args()
+    if args.command == "execute":
+        result = execute(config_from_environment())
+        print(json.dumps(result, sort_keys=True, separators=(",", ":")))
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

deploy/install/install_control_plane_host_seed_executor.sh

@@ -0,0 +1,52 @@
+#!/bin/sh
+set -eu
+
+if [ "$(id -u)" -ne 0 ]; then
+  echo "ROOT_REQUIRED" >&2
+  exit 20
+fi
+
+SOURCE_ROOT=${1:-}
+if [ -z "$SOURCE_ROOT" ]; then
+  echo "SOURCE_ROOT_REQUIRED" >&2
+  exit 21
+fi
+
+EXECUTOR="$SOURCE_ROOT/active-runtime/app/aios_control_plane_host_seed_executor.py"
+SERVICE="$SOURCE_ROOT/deploy/systemd/aios-control-plane-host-seed-executor.service"
+TIMER="$SOURCE_ROOT/deploy/systemd/aios-control-plane-host-seed-executor.timer"
+
+for file in "$EXECUTOR" "$SERVICE" "$TIMER"; do
+  if [ ! -f "$file" ] || [ -L "$file" ]; then
+    echo "SOURCE_FILE_INVALID:$file" >&2
+    exit 22
+  fi
+done
+
+AUTHORITY_GIT=/data/aios-gitops/repo.git
+REQUEST_REF=refs/heads/agent/host-seed-authorization-requests
+if [ ! -d "$AUTHORITY_GIT" ]; then
+  echo "AUTHORITATIVE_GIT_UNAVAILABLE" >&2
+  exit 23
+fi
+if ! id -u aios-bridge-staging >/dev/null 2>&1; then
+  echo "BRIDGE_SERVICE_ACCOUNT_UNAVAILABLE" >&2
+  exit 24
+fi
+if git --git-dir="$AUTHORITY_GIT" show-ref --verify --quiet "$REQUEST_REF"; then
+  echo "HOST_SEED_REQUEST_REF_ALREADY_PRESENT" >&2
+  exit 25
+fi
+
+install -d -m 0755 /usr/local/libexec
+install -m 0755 "$EXECUTOR" /usr/local/libexec/aios-control-plane-host-seed-executor
+install -m 0644 "$SERVICE" /etc/systemd/system/aios-control-plane-host-seed-executor.service
+install -m 0644 "$TIMER" /etc/systemd/system/aios-control-plane-host-seed-executor.timer
+install -d -m 0700 /var/lib/aios-control-plane-host-seed-executor
+
+systemctl daemon-reload
+systemctl enable --now aios-control-plane-host-seed-executor.timer
+systemctl is-enabled --quiet aios-control-plane-host-seed-executor.timer
+systemctl is-active --quiet aios-control-plane-host-seed-executor.timer
+
+echo "HOST_SEED_EXECUTOR_INSTALL=PASS"

deploy/install/rollback_control_plane_host_seed_executor.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+set -eu
+
+if [ "$(id -u)" -ne 0 ]; then
+  echo "ROOT_REQUIRED" >&2
+  exit 20
+fi
+
+systemctl disable --now aios-control-plane-host-seed-executor.timer 2>/dev/null || true
+rm -f /etc/systemd/system/aios-control-plane-host-seed-executor.timer
+rm -f /etc/systemd/system/aios-control-plane-host-seed-executor.service
+rm -f /usr/local/libexec/aios-control-plane-host-seed-executor
+systemctl daemon-reload
+
+echo "HOST_SEED_EXECUTOR_ROLLBACK=PASS"

deploy/systemd/aios-control-plane-host-seed-executor.service

@@ -0,0 +1,41 @@
+[Unit]
+Description=AIOS governed immutable Host seed executor
+After=local-fs.target
+
+[Service]
+Type=oneshot
+User=root
+Group=root
+UMask=0077
+Environment=PYTHONDONTWRITEBYTECODE=1
+Environment=AIOS_HOST_IDENTITY=cn-network-mkt
+Environment=AIOS_HOST_SEED_GIT_DIR=/data/aios-gitops/repo.git
+Environment=AIOS_HOST_SEED_TASK_BINDING_ROOT=/var/lib/aios-gitops/bridge-v2-staging/task-bindings
+Environment=AIOS_HOST_SEED_TASK_BINDING_OWNER=aios-bridge-staging
+Environment=AIOS_HOST_SEED_STATE_ROOT=/var/lib/aios-control-plane-host-seed-executor
+Environment=AIOS_HOST_SEED_RELEASE_ROOT=/opt/aios/releases
+Environment=AIOS_HOST_SEED_REQUEST_REF=refs/heads/agent/host-seed-authorization-requests
+Environment=AIOS_HOST_SEED_REQUEST_PATH=control-plane/host-seed/request.json
+ExecStart=/usr/bin/python3 -B /usr/local/libexec/aios-control-plane-host-seed-executor execute
+NoNewPrivileges=true
+PrivateTmp=true
+PrivateDevices=true
+ProtectSystem=strict
+ProtectHome=true
+ProtectKernelTunables=true
+ProtectKernelModules=true
+ProtectControlGroups=true
+ProtectKernelLogs=true
+LockPersonality=true
+RestrictSUIDSGID=true
+RestrictRealtime=true
+RestrictNamespaces=true
+MemoryDenyWriteExecute=true
+RestrictAddressFamilies=AF_UNIX
+IPAddressDeny=any
+CapabilityBoundingSet=CAP_DAC_OVERRIDE CAP_FOWNER CAP_CHOWN
+ReadOnlyPaths=/usr/local/libexec/aios-control-plane-host-seed-executor
+ReadOnlyPaths=/data/aios-gitops/repo.git
+ReadOnlyPaths=/var/lib/aios-gitops/bridge-v2-staging/task-bindings
+ReadWritePaths=/var/lib/aios-control-plane-host-seed-executor
+ReadWritePaths=/opt/aios/releases

deploy/systemd/aios-control-plane-host-seed-executor.timer

@@ -0,0 +1,12 @@
+[Unit]
+Description=Poll governed immutable Host seed requests
+
+[Timer]
+OnBootSec=2min
+OnUnitActiveSec=30s
+AccuracySec=1s
+Persistent=true
+Unit=aios-control-plane-host-seed-executor.service
+
+[Install]
+WantedBy=timers.target

docs/superpowers/specs/2026-08-22-server-local-governed-host-seed-executor.md

@@ -0,0 +1,117 @@
+# Server-local governed immutable Host seed executor
+
+Date: 2026-08-22
+
+## Goal
+
+Provide a server-local, fail-closed way to publish an already validated
+immutable control-plane candidate without depending on Windows, an external
+Agent worker, SSH, or an arbitrary root command channel.
+
+The executor is deliberately narrower than deployment:
+
+- it reads only the authoritative local Git object database;
+- it consumes one fixed request ref and path;
+- it accepts only `HOST_SEED_IMMUTABLE_CANDIDATE`;
+- it requires a high-risk governed-task binding whose description binds the
+  exact candidate intent *and* authorization expiry;
+- it materializes `base_oid + candidate.patch`, verifies every release-member
+  SHA against the candidate manifest, and verifies the candidate Machine Goal;
+- it atomically publishes one immutable directory under `/opt/aios/releases`;
+- it never starts or restarts services, starts the Projector, creates the fixed
+  continuation Task/Job, switches Production, or writes `main`, tags, or the
+  baseline.
+
+## Canonical server path
+
+```text
+explicit Owner HOST_SEED authorization
+  -> high-risk governed authorization task binding
+  -> governed request commit on refs/heads/agent/host-seed-authorization-requests
+  -> root timer polls local authoritative Git
+  -> validate exact intent, expiry, binding SHA, candidate evidence
+  -> read payload commit from local Git
+  -> shared disposable clone at exact base
+  -> apply declared patch
+  -> verify exact changed set + all release-member bytes
+  -> atomic immutable publish
+  -> durable sanitized receipt
+```
+
+The Host seed request is not the fixed continuation Task. The fixed
+continuation Task remains a separate later gate.
+
+## Trust and authorization binding
+
+The request contains an immutable `intent` with:
+
+- candidate / release id;
+- base OID and payload commit;
+- fixed patch, manifest, Machine Goal and bootstrap paths;
+- validation artifact SHA;
+- Manifest, Machine Goal, release-tree and bootstrap SHAs;
+- exact target Host identity.
+
+`intent_sha256` is the canonical SHA of that object. Authorization adds
+`task_id` and `expires_at`; those are hashed into `authorization_sha256`.
+The server-side governed-task binding must contain:
+
+```text
+risk=high
+description=HOST_SEED_AUTHORIZATION:<authorization_sha256>
+target_branch=agent/host-seed-authorization-...
+```
+
+The request also binds the exact byte SHA of that server-side binding. This
+prevents extending the authorization window or changing the candidate without
+creating a new governed authorization binding.
+
+The executor additionally requires the binding file to be a non-symlink
+regular file, not group/world writable, and owned by the configured Bridge
+service account in production.
+
+## Delivery model
+
+The live delivery payload is server-native Git data, not the external ZIP.
+The payload commit carries:
+
+```text
+control-plane/candidates/<candidate>/candidate.patch
+control-plane/candidates/<candidate>/implementation_manifest_*.json
+control-plane/candidates/<candidate>/machine_goal_*.json
+control-plane/candidates/<candidate>/aios_control_plane_immutable_seed_*.py
+```
+
+The external ZIP SHA remains bound as validation evidence through Machine
+Goal, but the executor records `artifact_delivery_used=false`: it does not
+claim that ZIP bytes were copied to the Host.
+
+The release tree itself is reconstructed and verified from authoritative Git
+objects plus the declared patch.
+
+## Idempotency and recovery
+
+Before publishing, the executor writes a durable `PENDING` operation record
+keyed by the exact intent SHA. The final receipt is `EXECUTED`.
+
+If the immutable release directory already exists, every member must match the
+manifest before the operation is accepted as idempotent. Any drift fails
+closed.
+
+A missing request ref is a normal `NO_REQUEST` poll and has no side effects.
+
+## Systemd confinement
+
+The service:
+
+- runs as root only because immutable release publication requires it;
+- has no network access;
+- reads authoritative Git and Bridge task bindings read-only;
+- can write only its private state root and `/opt/aios/releases`;
+- has no service-control, Projector, Task, Git-ref, Production, tag or baseline
+  operation in its code path.
+
+The timer polls every 30 seconds. Installing/enabling this executor is itself a
+separate governed control-plane deployment. Installing it does **not** grant a
+Host seed authorization and does not seed any candidate while the fixed
+request ref is absent.

tests/test_control_plane_host_seed_executor.py

@@ -0,0 +1,328 @@
+from __future__ import annotations
+
+from datetime import datetime, timedelta, timezone
+import hashlib
+import importlib.util
+import json
+from pathlib import Path
+import shutil
+import subprocess
+
+import pytest
+
+
+MODULE_PATH = Path(__file__).parents[1] / "active-runtime" / "app" / "aios_control_plane_host_seed_executor.py"
+spec = importlib.util.spec_from_file_location("host_seed_executor", MODULE_PATH)
+m = importlib.util.module_from_spec(spec)
+assert spec and spec.loader
+import sys
+sys.modules[spec.name] = m
+spec.loader.exec_module(m)
+
+
+def run(*args: str, cwd: Path) -> str:
+    return subprocess.check_output(args, cwd=cwd, text=True).strip()
+
+
+def sha(data: bytes) -> str:
+    return hashlib.sha256(data).hexdigest()
+
+
+def canonical(value: object) -> bytes:
+    return (json.dumps(value, sort_keys=True, separators=(",", ":")) + "\n").encode()
+
+
+def setup_case(tmp_path: Path, *, risk: str = "high", tamper_bootstrap: bool = False):
+    repo = tmp_path / "src"
+    bare = tmp_path / "repo.git"
+    repo.mkdir()
+    run("git", "init", "-b", "main", cwd=repo)
+    run("git", "config", "user.email", "test@example.invalid", cwd=repo)
+    run("git", "config", "user.name", "test", cwd=repo)
+    (repo / "a.txt").write_text("base\n", encoding="utf-8")
+    (repo / "bin.sh").write_text("#!/bin/sh\nexit 0\n", encoding="utf-8")
+    (repo / "bin.sh").chmod(0o755)
+    run("git", "add", "-A", cwd=repo)
+    run("git", "commit", "-m", "base", cwd=repo)
+    base = run("git", "rev-parse", "HEAD", cwd=repo)
+    run("git", "clone", "--bare", str(repo), str(bare), cwd=tmp_path)
+
+    (repo / "a.txt").write_text("changed\n", encoding="utf-8")
+    (repo / "c.txt").write_text("added\n", encoding="utf-8")
+    run("git", "add", "-N", "c.txt", cwd=repo)
+    patch = subprocess.check_output(["git", "diff", "--binary", base], cwd=repo)
+    after = {
+        "a.txt": sha((repo / "a.txt").read_bytes()),
+        "bin.sh": sha((repo / "bin.sh").read_bytes()),
+        "c.txt": sha((repo / "c.txt").read_bytes()),
+    }
+    package_members = {f"payload/repo/after/{k}": v for k, v in after.items()}
+    release_tree = sha(json.dumps({k: package_members[k] for k in sorted(package_members)}, sort_keys=True, separators=(",", ":")).encode())
+    manifest = {
+        "schema": "aios.control-plane-immutable-candidate.v6",
+        "candidate": "V9",
+        "repository": "aios/aios",
+        "base_oid": base,
+        "release_id": "control-plane-test-v9",
+        "changed_file_count": 2,
+        "changed_files": [
+            {"path": "a.txt", "status": "modified", "after_sha256": after["a.txt"]},
+            {"path": "c.txt", "status": "added", "after_sha256": after["c.txt"]},
+        ],
+        "release_member_count": 3,
+        "package_members": package_members,
+        "release_tree_sha256": release_tree,
+    }
+    manifest_raw = canonical(manifest)
+    bootstrap = b"#!/usr/bin/env python3\nprint('seed helper evidence only')\n"
+    bootstrap_sha = sha(bootstrap)
+    artifact_sha = "a" * 64
+    goal = {
+        "schema": "aios.control-plane-immutable-candidate-goal.v6",
+        "candidate": "V9",
+        "repository": "aios/aios",
+        "base_oid": base,
+        "release_id": "control-plane-test-v9",
+        "artifact_sha256": artifact_sha,
+        "manifest_sha256": sha(manifest_raw),
+        "release_tree_sha256": release_tree,
+        "seed_bootstrap_sha256": bootstrap_sha,
+        "host_seed_authorized": False,
+    }
+    goal_raw = canonical(goal)
+
+    # Reset the source worktree to base; delivery files live in a separate commit.
+    run("git", "reset", "--hard", base, cwd=repo)
+    delivery = repo / "control-plane" / "candidates" / "v9"
+    delivery.mkdir(parents=True)
+    (delivery / "candidate.patch").write_bytes(patch)
+    (delivery / "implementation_manifest_v9.json").write_bytes(manifest_raw)
+    (delivery / "machine_goal_v9.json").write_bytes(goal_raw)
+    (delivery / "aios_control_plane_immutable_seed_v9.py").write_bytes(
+        b"tampered\n" if tamper_bootstrap else bootstrap
+    )
+    run("git", "add", "-A", cwd=repo)
+    run("git", "commit", "-m", "candidate payload", cwd=repo)
+    payload_commit = run("git", "rev-parse", "HEAD", cwd=repo)
+    run("git", "push", str(bare), f"{payload_commit}:refs/heads/agent/candidate-payload", cwd=repo)
+
+    intent = {
+        "candidate": "V9",
+        "release_id": "control-plane-test-v9",
+        "base_oid": base,
+        "payload_commit": payload_commit,
+        "patch_path": "control-plane/candidates/v9/candidate.patch",
+        "manifest_path": "control-plane/candidates/v9/implementation_manifest_v9.json",
+        "machine_goal_path": "control-plane/candidates/v9/machine_goal_v9.json",
+        "seed_bootstrap_path": "control-plane/candidates/v9/aios_control_plane_immutable_seed_v9.py",
+        "artifact_sha256": artifact_sha,
+        "manifest_sha256": sha(manifest_raw),
+        "machine_goal_sha256": sha(goal_raw),
+        "release_tree_sha256": release_tree,
+        "seed_bootstrap_sha256": bootstrap_sha,
+        "target_host": "cn-network-mkt",
+    }
+    intent_digest = sha(canonical(intent))
+    task_id = "host-seed-authz-v9-cn-network-mkt"
+    now = datetime(2026, 8, 22, 12, 0, tzinfo=timezone.utc)
+    expires_text = (now + timedelta(minutes=30)).isoformat().replace("+00:00", "Z")
+    authorization_digest = sha(canonical({
+        "task_id": task_id,
+        "intent_sha256": intent_digest,
+        "expires_at": expires_text,
+    }))
+    binding = {
+        "task_id": task_id,
+        "repository": "aios/aios",
+        "base_oid": payload_commit,
+        "target_branch": "agent/host-seed-authorization-v9-cn-network-mkt",
+        "risk": risk,
+        "description": "HOST_SEED_AUTHORIZATION:" + authorization_digest,
+        "idempotency_key": "host-seed-authz-v9-1",
+        "expected_branch_oid": payload_commit,
+        "branch_mode": "CREATE_NEW",
+        "generation": 1,
+        "job_id": "job-" + "1" * 32,
+    }
+    binding_root = tmp_path / "bindings"
+    binding_root.mkdir()
+    binding_raw = json.dumps(binding, sort_keys=True).encode()
+    (binding_root / f"{task_id}.json").write_bytes(binding_raw)
+    (binding_root / f"{task_id}.json").chmod(0o600)
+
+    request = {
+        "schema": "aios.control-plane-host-seed-request.v1",
+        "operation": "HOST_SEED_IMMUTABLE_CANDIDATE",
+        "repository": "aios/aios",
+        "intent": intent,
+        "authorization": {
+            "task_id": task_id,
+            "binding_sha256": sha(binding_raw),
+            "expires_at": expires_text,
+            "intent_sha256": intent_digest,
+            "authorization_sha256": authorization_digest,
+        },
+    }
+    request_path = repo / "control-plane" / "host-seed" / "request.json"
+    request_path.parent.mkdir(parents=True, exist_ok=True)
+    request_path.write_bytes(canonical(request))
+    run("git", "add", str(request_path.relative_to(repo)), cwd=repo)
+    run("git", "commit", "-m", "host seed request", cwd=repo)
+    request_commit = run("git", "rev-parse", "HEAD", cwd=repo)
+    run("git", "push", str(bare), f"{request_commit}:{m.REQUEST_REF}", cwd=repo)
+
+    config = m.Config(
+        git_dir=bare,
+        task_binding_root=binding_root,
+        state_root=tmp_path / "state",
+        release_root=tmp_path / "releases",
+        host_identity="cn-network-mkt",
+        task_binding_owner=None,
+    )
+    return config, now, after, request
+
+
+def test_execute_publishes_exact_release_and_is_idempotent(tmp_path: Path):
+    config, now, after, request = setup_case(tmp_path)
+    receipt = m.execute(config, now=now, require_root=False)
+    assert receipt["state"] == "EXECUTED"
+    assert receipt["service_mutation"] is False
+    assert receipt["service_restart"] is False
+    assert receipt["projector_started"] is False
+    assert receipt["task_creation"] is False
+    assert receipt["production_write"] is False
+    final = config.release_root / "control-plane-test-v9"
+    assert final.is_dir() and not final.is_symlink()
+    assert final.stat().st_mode & 0o777 == 0o755
+    assert sha((final / "a.txt").read_bytes()) == after["a.txt"]
+    assert sha((final / "bin.sh").read_bytes()) == after["bin.sh"]
+    assert sha((final / "c.txt").read_bytes()) == after["c.txt"]
+    assert (final / "bin.sh").stat().st_mode & 0o111
+    again = m.execute(config, now=now, require_root=False)
+    assert again == receipt
+
+
+def test_execute_rejects_non_high_risk_authorization(tmp_path: Path):
+    config, now, _, _ = setup_case(tmp_path, risk="engineering")
+    with pytest.raises(m.HostSeedError, match="AUTHORIZATION_RISK_MISMATCH"):
+        m.execute(config, now=now, require_root=False)
+    assert not config.release_root.exists()
+
+
+def test_execute_rejects_tampered_seed_bootstrap(tmp_path: Path):
+    config, now, _, _ = setup_case(tmp_path, tamper_bootstrap=True)
+    with pytest.raises(m.HostSeedError, match="SEED_BOOTSTRAP_HASH_MISMATCH"):
+        m.execute(config, now=now, require_root=False)
+    assert not config.release_root.exists()
+
+
+def test_request_rejects_wrong_host(tmp_path: Path):
+    config, now, _, _ = setup_case(tmp_path)
+    config = m.Config(
+        git_dir=config.git_dir,
+        task_binding_root=config.task_binding_root,
+        state_root=config.state_root,
+        release_root=config.release_root,
+        host_identity="other-host",
+        task_binding_owner=None,
+    )
+    with pytest.raises(m.HostSeedError, match="TARGET_HOST_MISMATCH"):
+        m.execute(config, now=now, require_root=False)
+
+
+def test_existing_release_drift_is_fail_closed(tmp_path: Path):
+    config, now, _, _ = setup_case(tmp_path)
+    first = m.execute(config, now=now, require_root=False)
+    assert first["state"] == "EXECUTED"
+    (config.release_root / "control-plane-test-v9" / "a.txt").write_text("drift\n")
+    # remove durable receipt so existing-release verification path is exercised.
+    for p in (config.state_root / "receipts").glob("*.json"):
+        p.unlink()
+    with pytest.raises(m.HostSeedError, match="EXISTING_RELEASE_HASH_MISMATCH"):
+        m.execute(config, now=now, require_root=False)
+
+
+def test_no_request_ref_is_safe_noop(tmp_path: Path):
+    repo = tmp_path / "src"
+    bare = tmp_path / "repo.git"
+    repo.mkdir()
+    run("git", "init", "-b", "main", cwd=repo)
+    run("git", "config", "user.email", "test@example.invalid", cwd=repo)
+    run("git", "config", "user.name", "test", cwd=repo)
+    (repo / "a").write_text("x\n")
+    run("git", "add", "a", cwd=repo)
+    run("git", "commit", "-m", "base", cwd=repo)
+    run("git", "clone", "--bare", str(repo), str(bare), cwd=tmp_path)
+    cfg = m.Config(
+        git_dir=bare,
+        task_binding_root=tmp_path / "bindings",
+        state_root=tmp_path / "state",
+        release_root=tmp_path / "releases",
+        host_identity="cn-network-mkt",
+        task_binding_owner=None,
+    )
+    result = m.execute(cfg, now=datetime(2026, 8, 22, tzinfo=timezone.utc), require_root=False)
+    assert result["state"] == "NO_REQUEST"
+    assert result["service_mutation"] is False
+    assert result["task_creation"] is False
+    assert not cfg.release_root.exists()
+
+
+def test_authorization_expiry_cannot_be_extended_without_new_binding(tmp_path: Path):
+    config, now, _, _ = setup_case(tmp_path)
+    # Rewrite only the request expiry and recompute the request commit, but keep
+    # the original governed-task binding description. The authorization digest
+    # therefore no longer matches the binding and must fail closed.
+    repo = tmp_path / "src"
+    req_path = repo / "control-plane" / "host-seed" / "request.json"
+    value = json.loads(req_path.read_text())
+    value["authorization"]["expires_at"] = (now + timedelta(minutes=45)).isoformat().replace("+00:00", "Z")
+    value["authorization"]["authorization_sha256"] = sha(canonical({
+        "task_id": value["authorization"]["task_id"],
+        "intent_sha256": value["authorization"]["intent_sha256"],
+        "expires_at": value["authorization"]["expires_at"],
+    }))
+    req_path.write_bytes(canonical(value))
+    run("git", "add", str(req_path.relative_to(repo)), cwd=repo)
+    run("git", "commit", "-m", "tamper expiry", cwd=repo)
+    new_commit = run("git", "rev-parse", "HEAD", cwd=repo)
+    run("git", "push", "--force", str(config.git_dir), f"{new_commit}:{m.REQUEST_REF}", cwd=repo)
+    with pytest.raises(m.HostSeedError, match="AUTHORIZATION_DESCRIPTION_MISMATCH"):
+        m.execute(config, now=now, require_root=False)
+
+
+def test_systemd_contract_has_no_network_or_implicit_activation():
+    root = Path(__file__).parents[1]
+    service = (root / "deploy/systemd/aios-control-plane-host-seed-executor.service").read_text()
+    timer = (root / "deploy/systemd/aios-control-plane-host-seed-executor.timer").read_text()
+    assert "User=root" in service
+    assert "IPAddressDeny=any" in service
+    assert "RestrictAddressFamilies=AF_UNIX" in service
+    assert "ReadOnlyPaths=/data/aios-gitops/repo.git" in service
+    assert "ReadWritePaths=/opt/aios/releases" in service
+    assert "systemctl start" not in service
+    assert "projector" not in service.lower()
+    assert "OnUnitActiveSec=30s" in timer
+
+
+def test_release_root_symlink_is_rejected(tmp_path: Path):
+    config, now, _, _ = setup_case(tmp_path)
+    real = tmp_path / "real-releases"
+    real.mkdir()
+    config.release_root.symlink_to(real, target_is_directory=True)
+    with pytest.raises(m.HostSeedError, match="RELEASE_ROOT_SYMLINK_REJECTED"):
+        m.execute(config, now=now, require_root=False)
+
+def test_install_and_rollback_scripts_have_valid_bash_syntax():
+    root = Path(__file__).parents[1]
+    for relative in (
+        "deploy/install/install_control_plane_host_seed_executor.sh",
+        "deploy/install/rollback_control_plane_host_seed_executor.sh",
+    ):
+        subprocess.run(
+            ["/usr/bin/bash", "-n", str(root / relative)],
+            check=True,
+            text=True,
+            capture_output=True,
+        )
+