docs: sharpen the attribution guarantee to a byte<->activation-key binding

Revised per PR #480 (#5607 owner clarification + #5608 codex resolution;
#5612 directs the update):

- The audit row no longer implies upstream observation or agent-only
  authorship. Reworded the guarantee: the row cryptographically binds
  commit bytes (control-plane-RECOMPUTED SHA) to access to the activation
  signing key, and binds that key to control-plane-owned activation
  metadata. An agent can sign arbitrary contents but cannot verify as a
  different activation or choose the recorded metadata.
- Control plane accepts gateway-delivered opaque bytes, independently
  recomputes the Git object ID, verifies the embedded signature against
  the activation key, and stamps its own metadata. Trusts no gateway
  SHA/key/verdict/metadata. No upstream fetch.
- Purged overclaims: removed "a compromised gateway cannot fabricate an
  audit binding" (the sidecar holds the signing capability, so it can —
  and that's acceptable under the intended guarantee), plus "accepted
  push" / "introduced upstream" framing.
- Resolved the control-plane-transport open question in-PRD (was left
  open; codex asked to resolve): transport is gateway bytes +
  recompute + verify; mirror-read is no stronger.

Issue: #423

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

bot_bottle/backend/docker/orchestrator.py

@@ -19,7 +19,6 @@ from .util import run_docker
 from ...paths import (
     ORCHESTRATOR_TOKEN_ENV,
     bot_bottle_root,
-    host_orchestrator_token,
 )
 from ...gateway import GatewayError
 from ...orchestrator.lifecycle import (
@@ -171,7 +170,9 @@ class DockerOrchestrator(Orchestrator):
         fixed-name container first)."""
         self._ensure_control_network()
         run_docker(["docker", "rm", "--force", self.name])
-        _signing_key = host_orchestrator_token()
+        # The signing key comes through the shared provisioning contract (#476),
+        # which fail-closes rather than yield an empty key that would run OPEN.
+        _signing_key = self.control_plane_key()
         proc = run_docker([
             "docker", "run", "--detach",
             "--name", self.name,

bot_bottle/backend/firecracker/orchestrator.py

@@ -21,7 +21,6 @@ import time
 from pathlib import Path
 
 from ...log import die, info
-from ...paths import host_orchestrator_token
 from ...orchestrator.lifecycle import (
     DEFAULT_STARTUP_TIMEOUT_SECONDS,
     Orchestrator,
@@ -108,11 +107,13 @@ class FirecrackerOrchestrator(Orchestrator):
             data_drive=self._ensure_registry_volume(),
         )
         # Push the host-canonical signing key (the init waits for it before
-        # starting the control plane). The host token file stays the single
+        # starting the control plane). It comes through the shared provisioning
-        # source of truth, so a co-running docker/macOS control plane keeps
+        # contract (#476) — the same host token file every backend uses, so a
-        # working; the guest verifies tokens with the same key the CLI signs from.
+        # co-running docker/macOS control plane keeps working and the guest
+        # verifies tokens with the same key the CLI signs from; fail-closed, so
+        # the guest is never handed an empty key that would run it OPEN.
         infra_vm.push_secret(
-            vm, host_orchestrator_token(), infra_vm._GUEST_SIGNING_KEY_PATH,
+            vm, self.control_plane_key(), infra_vm._GUEST_SIGNING_KEY_PATH,
             "the control-plane signing key to the orchestrator VM "
             "(its control plane will not start)",
         )

bot_bottle/backend/macos_container/orchestrator.py

@@ -18,10 +18,7 @@ import urllib.request
 from pathlib import Path
 
 from ... import log
-from ...paths import (
+from ...paths import ORCHESTRATOR_TOKEN_ENV
-    ORCHESTRATOR_TOKEN_ENV,
-    host_orchestrator_token,
-)
 from ...orchestrator.lifecycle import (
     DEFAULT_HEALTH_TIMEOUT_SECONDS,
     DEFAULT_PORT,
@@ -134,7 +131,9 @@ class MacosOrchestrator(Orchestrator):
 
     def _run_container(self, current_hash: str) -> None:
         container_mod.force_remove_container(self.name)
-        _signing_key = host_orchestrator_token()
+        # The signing key comes through the shared provisioning contract (#476),
+        # which fail-closes rather than yield an empty key that would run OPEN.
+        _signing_key = self.control_plane_key()
         argv = [
             "container", "run", "--detach",
             "--name", self.name,

bot_bottle/orchestrator/client.py

@@ -18,8 +18,8 @@ import urllib.request
 from collections.abc import Iterable
 from dataclasses import dataclass
 
-from ..orchestrator_auth import ROLE_CLI, mint
+from ..orchestrator_auth import ROLE_CLI
-from ..paths import host_orchestrator_token
+from ..trust_domain import CONTROL_PLANE
 from .server import ORCHESTRATOR_AUTH_HEADER
 
 DEFAULT_TIMEOUT_SECONDS = 5.0
@@ -32,7 +32,7 @@ def _host_auth_token() -> str:
     "" means 'send no auth header' — correct against an open (unconfigured)
     control plane, and harmlessly rejected by a secured one."""
     try:
-        return mint(ROLE_CLI, host_orchestrator_token())
+        return CONTROL_PLANE.mint(ROLE_CLI)
     except (OSError, ValueError):
         return ""
 

bot_bottle/orchestrator/lifecycle.py

@@ -21,8 +21,7 @@ import urllib.error
 import urllib.request
 from pathlib import Path
 
-from ..orchestrator_auth import ROLE_GATEWAY, mint
+from ..trust_domain import ControlPlaneProvisioning
-from ..paths import host_orchestrator_token
 
 DEFAULT_PORT = 8099
 DEFAULT_STARTUP_TIMEOUT_SECONDS = 45.0
@@ -58,6 +57,12 @@ class Orchestrator(abc.ABC):
     so it — not the gateway — mints the gateway's role-scoped token.
     Backend-neutral."""
 
+    # The shared control-plane auth provisioning contract (#476). Every backend
+    # gets its signing key + gateway token through this one seam rather than
+    # re-deriving the wiring; it is fail-closed for every backend — the
+    # orchestrator never starts without its signing key.
+    provisioning: ControlPlaneProvisioning = ControlPlaneProvisioning()
+
     def ensure_built(self) -> None:
         """Ensure the orchestrator's image / rootfs exists, building it if
         needed. Default: nothing to build (e.g. a pre-pulled image). Call before
@@ -105,9 +110,17 @@ class Orchestrator(abc.ABC):
     def mint_gateway_token(self) -> str:
         """Mint a role-scoped `gateway` JWT from the host signing key for the
         gateway to present. The orchestrator holds the key; the gateway never
-        does (#469). Backend-neutral — the same host token file is the single
+        does (#469). Routed through the shared provisioning contract (#476), so
-        source of truth across backends."""
+        the same host token file is the single source of truth across backends."""
-        return mint(ROLE_GATEWAY, host_orchestrator_token())
+        return self.provisioning.gateway_token()
+
+    def control_plane_key(self) -> str:
+        """The raw signing key the control-plane *process* must receive — the ONE
+        place a backend obtains it (docker/macOS inject it as `key_env`;
+        firecracker pushes it to the guest). Fail-closed via the provisioning
+        contract: it raises rather than yield an empty key that would run the
+        server OPEN (#476)."""
+        return self.provisioning.orchestrator_key()
 
 
 __all__ = [
@@ -117,4 +130,5 @@ __all__ = [
     "OrchestratorStartError",
     "source_hash",
     "Orchestrator",
+    "ControlPlaneProvisioning",
 ]

bot_bottle/orchestrator/server.py

@@ -63,8 +63,8 @@ import sys
 import typing
 from urllib.parse import urlsplit
 
-from ..orchestrator_auth import ROLE_CLI, ROLES, verify
+from ..orchestrator_auth import ROLE_CLI, ROLES
-from ..paths import ORCHESTRATOR_TOKEN_ENV
+from ..trust_domain import CONTROL_PLANE
 from ..supervisor.types import TOOLS
 from .service import OrchestratorCore
 
@@ -413,11 +413,13 @@ class OrchestratorServer(socketserver.ThreadingMixIn, http.server.HTTPServer):
 
     def __init__(self, address: tuple[str, int], orchestrator: OrchestratorCore) -> None:
         self.orchestrator = orchestrator
-        self._signing_key = os.environ.get(ORCHESTRATOR_TOKEN_ENV, "").strip()
+        # The control-plane trust domain's signing key, as injected into THIS
+        # (the owning) process by the launcher (#476). Unset → open mode below.
+        self._signing_key = CONTROL_PLANE.key_from_env()
         if not self._signing_key:
             sys.stderr.write(
                 "orchestrator: WARNING — no control-plane signing key "
-                f"(${ORCHESTRATOR_TOKEN_ENV}); running WITHOUT caller "
+                f"(${CONTROL_PLANE.key_env}); running WITHOUT caller "
                 "authentication. Any client that can reach this port can drive "
                 "it. Backends that put the control plane on an agent-reachable "
                 "network MUST set this.\n"
@@ -433,7 +435,7 @@ class OrchestratorServer(socketserver.ThreadingMixIn, http.server.HTTPServer):
         role (→ per-route 401/403 in `dispatch`)."""
         if not self._signing_key:
             return ROLE_CLI
-        return verify(presented, self._signing_key)
+        return CONTROL_PLANE.verify(presented, self._signing_key)
 
 
 def make_server(

bot_bottle/orchestrator_auth.py

@@ -59,12 +59,17 @@ _HEADER_SEGMENT = _b64url_encode(
 )
 
 
-def mint(role: str, secret: str) -> str:
+def mint(role: str, secret: str, *, roles: frozenset[str] = ROLES) -> str:
     """A compact HS256 token asserting `role`, signed with `secret`.
 
-    Raises ValueError for an unknown role (mint only what the control plane will
+    `roles` is the set the signing key is allowed to sign (default: the
-    accept) or an empty signing key (an unsigned credential is never valid)."""
+    orchestrator's `{gateway, cli}`). A separate service (e.g. the host
-    if role not in ROLES:
+    controller) passes its own key + role set so its tokens can't be forged with
+    the orchestrator's key — see `trust_domain.py`, issues #476/#468.
+
+    Raises ValueError for a role outside `roles`, or an empty signing key (an
+    unsigned credential is never valid)."""
+    if role not in roles:
         raise ValueError(f"unknown control-plane role {role!r}")
     if not secret:
         raise ValueError("cannot mint a control-plane token without a signing key")
@@ -73,10 +78,11 @@ def mint(role: str, secret: str) -> str:
     return f"{signing_input}.{_sign(secret, signing_input)}"
 
 
-def verify(token: str, secret: str) -> str | None:
+def verify(token: str, secret: str, *, roles: frozenset[str] = ROLES) -> str | None:
     """The role a valid `token` carries, or None if it is malformed, wrongly
-    signed, or names an unknown role. Constant-time signature check; rejects any
+    signed, or names a role outside `roles` (the verifying trust domain's set —
-    header whose alg isn't HS256 (no alg-confusion / `none`)."""
+    default `{gateway, cli}`). Constant-time signature check; rejects any header
+    whose alg isn't HS256 (no alg-confusion / `none`)."""
     if not token or not secret:
         return None
     parts = token.split(".")
@@ -94,7 +100,7 @@ def verify(token: str, secret: str) -> str | None:
     if not isinstance(header, dict) or header.get("alg") != _ALG:
         return None
     role = payload.get("role") if isinstance(payload, dict) else None
-    return role if isinstance(role, str) and role in ROLES else None
+    return role if isinstance(role, str) and role in roles else None
 
 
 __all__ = ["ROLE_GATEWAY", "ROLE_CLI", "ROLES", "mint", "verify"]

bot_bottle/paths.py

@@ -97,16 +97,17 @@ def host_gateway_ca_dir() -> Path:
     return ca_dir
 
 
-def host_orchestrator_token() -> str:
+def host_signing_key(filename: str) -> str:
-    """The per-host control-plane secret, minted (256-bit, url-safe) and
+    """A per-host signing key at `<root>/<filename>`, minted (256-bit, url-safe)
-    persisted 0600 on first use, then reused.
+    and persisted 0600 on first use, then reused.
 
-    This is the shared secret the launchers inject into the control-plane and
+    The generic form of `host_orchestrator_token()`: each service names its own
-    gateway containers and that the host CLI presents on every call. It is a
+    key file (`trust_domain.py`), so the orchestrator and a separate service like
-    *host* artifact — the file lives under the root the agent never mounts, and
+    the host controller (#468) get distinct keys neither can read. It is a *host*
-    the env var is set only on the trusted containers — so reading it here is
+    artifact — the file lives under the root the agent never mounts, and its value
-    safe on the host launch path but the value never reaches a bottle."""
+    is injected only into the trusted control-plane process — so reading it here
-    path = bot_bottle_root() / ORCHESTRATOR_TOKEN_FILENAME
+    is safe on the launch path but the value never reaches a bottle."""
+    path = bot_bottle_root() / filename
     try:
         existing = path.read_text().strip()
         if existing:
@@ -128,6 +129,14 @@ def host_orchestrator_token() -> str:
     return token
 
 
+def host_orchestrator_token() -> str:
+    """The per-host control-plane signing key — the host-canonical key the
+    launchers inject into the control-plane process and the host CLI mints its
+    own `cli` token from. The `control-plane` trust domain's specialization of
+    `host_signing_key()`."""
+    return host_signing_key(ORCHESTRATOR_TOKEN_FILENAME)
+
+
 __all__ = [
     "HOST_DB_FILENAME",
     "ORCHESTRATOR_TOKEN_FILENAME",
@@ -138,5 +147,6 @@ __all__ = [
     "host_db_path",
     "host_db_dir",
     "host_gateway_ca_dir",
+    "host_signing_key",
     "host_orchestrator_token",
 ]

bot_bottle/trust_domain.py

@@ -0,0 +1,140 @@
+"""Per-service control-plane signing keys (issue #476).
+
+A `TrustDomain` is one service's signing material: its host-canonical key file,
+the roles that key may sign, and the env vars its key and a pre-minted token ride
+in. Scoping `mint`/`verify` to a domain's roles keeps one service's key from
+signing (or accepting) another service's tokens.
+
+Today there is one domain, `CONTROL_PLANE` — the orchestrator's key (roles
+`{gateway, cli}`): the orchestrator holds it and mints the gateway's and CLI's
+tokens. The host controller (#468) will add a **second** domain with its own key
+the orchestrator never holds. That is the point: the host controller starts and
+stops the orchestrator, so the orchestrator must not be able to mint the
+credentials it uses to talk to it. Adding a `host` role to `CONTROL_PLANE`
+instead would defeat that — the orchestrator holds that key, so it could forge
+`host` tokens.
+
+`ControlPlaneProvisioning` is the one seam every backend launcher uses to get the
+orchestrator its key and the gateway its token, instead of re-deriving that
+wiring per backend (the bug class behind PR #471 — see
+`docs/prds/prd-new-control-plane-auth-provisioning.md`).
+
+Stdlib-only: the HMAC lives in `orchestrator_auth`, the key file in `paths`.
+"""
+
+from __future__ import annotations
+
+import os
+from collections.abc import Mapping
+from dataclasses import dataclass
+
+from . import orchestrator_auth
+from .orchestrator_auth import ROLE_GATEWAY
+from .paths import (
+    ORCHESTRATOR_AUTH_JWT_ENV,
+    ORCHESTRATOR_TOKEN_ENV,
+    ORCHESTRATOR_TOKEN_FILENAME,
+    host_signing_key,
+)
+
+
+class ProvisioningError(RuntimeError):
+    """A control-plane auth invariant would be violated (e.g. starting the
+    orchestrator without its signing key — which would run OPEN)."""
+
+
+@dataclass(frozen=True)
+class TrustDomain:
+    """One service's signing material: a host-canonical key file, the roles that
+    key may sign, and the env vars its key and a minted token ride in.
+
+    The service that *owns* the domain (e.g. the orchestrator) receives the raw
+    key via `key_env`; a delegate (e.g. the gateway) receives only a pre-minted,
+    role-scoped token via `token_env` it cannot rewrite. `mint`/`verify` are
+    scoped to `roles`, so this service's key can neither sign nor accept another
+    service's role."""
+
+    name: str
+    key_filename: str
+    roles: frozenset[str]
+    key_env: str
+    token_env: str
+
+    def signing_key(self) -> str:
+        """This service's host-canonical signing key (minted 0600 on first use).
+        Host-side only — the value is injected into the owning process."""
+        return host_signing_key(self.key_filename)
+
+    def key_from_env(self, environ: Mapping[str, str] | None = None) -> str:
+        """The signing key as the owning process sees it — read from `key_env`
+        (default `os.environ`). "" when unset; the caller decides whether that is
+        fatal (`ControlPlaneProvisioning`) or the open-mode fallback
+        (`OrchestratorServer`)."""
+        env = os.environ if environ is None else environ
+        return env.get(self.key_env, "").strip()
+
+    def mint(self, role: str) -> str:
+        """A role-scoped token for a delegate, signed with this service's key.
+        Raises ValueError for a role this service doesn't sign."""
+        if role not in self.roles:
+            raise ValueError(f"role {role!r} is not in trust domain {self.name!r}")
+        return orchestrator_auth.mint(role, self.signing_key(), roles=self.roles)
+
+    def verify(self, token: str, key: str) -> str | None:
+        """The role `token` carries under `key`, or None. `key` is passed in
+        (not read from disk) because the verifier — the control-plane process —
+        holds it in `key_env`, not on disk in its guest."""
+        return orchestrator_auth.verify(token, key, roles=self.roles)
+
+
+# The orchestrator's domain: the key the orchestrator (and host CLI) holds, the
+# `gateway` token it mints for the data plane, and the `cli` token the CLI mints
+# for itself. #468's host controller will add a second, separate domain.
+CONTROL_PLANE = TrustDomain(
+    name="control-plane",
+    key_filename=ORCHESTRATOR_TOKEN_FILENAME,
+    roles=orchestrator_auth.ROLES,
+    key_env=ORCHESTRATOR_TOKEN_ENV,
+    token_env=ORCHESTRATOR_AUTH_JWT_ENV,
+)
+
+
+@dataclass(frozen=True)
+class ControlPlaneProvisioning:
+    """The one seam every backend launcher uses to provision control-plane auth,
+    instead of re-deriving the four invariants that each cost a PR #471 review
+    round: the orchestrator gets the raw key (`orchestrator_key`), the gateway
+    gets a minted `gateway` token (`gateway_token`), the host CLI mints its own
+    `cli` token from the same host-canonical key, and the orchestrator never
+    starts open."""
+
+    domain: TrustDomain = CONTROL_PLANE
+
+    def orchestrator_key(self) -> str:
+        """The raw signing key the orchestrator process must receive (carry it in
+        `domain.key_env`). Fail-closed: raises rather than return "", since an
+        empty key runs the server open — and being on a separate host does not
+        stop the gateway from reaching the control plane (it must, for
+        `/resolve`), so an open orchestrator would treat that gateway as `cli`."""
+        key = self.domain.signing_key()
+        if not key:
+            raise ProvisioningError(
+                f"refusing to start the {self.domain.name} orchestrator without "
+                "a signing key: an open orchestrator authenticates no one and "
+                "grants every caller that reaches it full `cli` (#476)"
+            )
+        return key
+
+    def gateway_token(self) -> str:
+        """The `gateway`-role token the gateway receives (carry it in
+        `domain.token_env`) — minted from the key, never the key itself, so a
+        compromised gateway cannot forge a `cli` token."""
+        return self.domain.mint(ROLE_GATEWAY)
+
+
+__all__ = [
+    "ProvisioningError",
+    "TrustDomain",
+    "CONTROL_PLANE",
+    "ControlPlaneProvisioning",
+]

docs/prds/prd-new-control-plane-auth-provisioning.md

@@ -0,0 +1,89 @@
+# PRD prd-new: Per-service signing keys for control-plane auth
+
+- **Status:** Draft
+- **Author:** claude
+- **Created:** 2026-07-26
+- **Issue:** #476
+
+## Summary
+
+Provision control-plane signing keys **per service**, through one shared seam, so
+no service can mint another's credentials. Concretely: the orchestrator holds the
+control-plane key and mints the gateway's and CLI's tokens; the host controller
+(#468, next) gets a **separate** key the orchestrator never holds — so the
+orchestrator cannot forge the credentials it uses to talk to the host controller
+that starts and stops it. Landing this seam also retires the per-backend
+provisioning duplication that made PR #471 take three review rounds.
+
+## Problem
+
+**1. The orchestrator could forge host-controller credentials.** The
+orchestrator's key signs roles `{gateway, cli}`. The tempting way to add the host
+controller (#468) is a third role, `host`, on that same key. But then the
+orchestrator — which holds the key — can mint `host` tokens, and the host
+controller, which owns the orchestrator's lifecycle, must not trust anything the
+orchestrator can mint. The two services need separate keys.
+
+**2. Every backend provisioned auth by hand.** Each launcher (docker
+gateway/infra, macOS infra, firecracker infra) re-derived how to generate the
+signing key, scope it to the orchestrator, mint the gateway JWT, and keep the
+host key file canonical. All three PR #471 High-severity findings were this one
+integration bug in different launchers: the data plane got the full `cli` token;
+the firecracker control plane ran open; the firecracker guest clobbered the host
+key.
+
+## Goals / Success Criteria
+
+- The orchestrator and the host controller sign with **different** keys; neither
+  can mint the other's tokens. (This PR provisions the orchestrator's key and
+  leaves a drop-in seam for the host controller's.)
+- One shared provisioning seam every backend uses — a new backend or daemon
+  implements it instead of rediscovering these four invariants:
+  1. the signing key is host-canonical: a guest is handed it, never generates or
+     overwrites it;
+  2. only the orchestrator process gets the raw key; the gateway gets a
+     pre-minted `gateway` token it can't rewrite into `cli`;
+  3. the host CLI's `cli` token is minted from the same key, so it stays valid
+     across co-running backends;
+  4. the orchestrator never runs open — the signing key is mandatory, with no
+     topology opt-out (a separate host does not stop a caller from reaching the
+     control-plane listener, so it cannot make open mode safe).
+
+## Non-goals
+
+- The host controller itself (#468) — this only provisions the orchestrator's
+  key and the seam #468 plugs into.
+- Rewriting the HMAC primitive: `orchestrator_auth.mint/verify` gain an optional
+  `roles=` arg (default unchanged) so a key can carry a different role set;
+  nothing else changes.
+- Network topology, the plane split (#469), or the server's open-mode fallback
+  for tests.
+
+## Design
+
+A **`TrustDomain`** is one service's signing material: its host-canonical key
+file, the roles that key may sign, and the env vars its key and a pre-minted
+token ride in. `mint`/`verify` are scoped to that domain's roles, so a token
+signed by one service's key neither carries nor verifies another service's role.
+
+- `CONTROL_PLANE` — the orchestrator's domain: key `orchestrator-token`, roles
+  `{gateway, cli}`. The orchestrator process holds the key; the gateway holds
+  only a minted `gateway` token; the host CLI mints its own `cli` token.
+- The host controller (#468) will add a second `TrustDomain` — its own key file
+  and role(s) — that the orchestrator never holds.
+
+**`ControlPlaneProvisioning`** is the seam the backends call.
+`orchestrator_key()` returns the raw key for the control-plane process
+(fail-closed for every backend: it raises rather than hand back an empty key that
+would run the server open). `gateway_token()` mints the gateway's token. Each backend applies these through its own transport —
+docker/macOS inject env vars, firecracker pushes over SSH — but none re-derives
+*which* key or role.
+
+`paths.host_signing_key(filename)` generalizes `host_orchestrator_token()` so each
+domain names its own key file.
+
+## Open questions
+
+None blocking. #468 adds its `TrustDomain` and a second
+`ControlPlaneProvisioning`-shaped consumer; renaming that class to something
+service-neutral is a cosmetic call to make then.

docs/prds/prd-new-signed-commits-attribution.md

@@ -0,0 +1,463 @@
+# PRD prd-new: Per-bottle signed commits & audit attribution
+
+- **Status:** Draft
+- **Author:** didericis-claude
+- **Created:** 2026-07-25
+- **Issue:** #423
+
+## Summary
+
+Give each bottled agent a **per-activation signing key** so that every commit it
+produces is signed in the git-gate trust boundary (outside the bottle) and
+recorded in bot-bottle's own **host-owned audit store**, which is the portable
+source of truth. Each row cryptographically binds a commit's bytes (and their
+control-plane-recomputed SHA) to **access to that activation's signing key**, and
+binds the key to control-plane-owned activation metadata — bottle, host,
+manifest, agent, activation interval, retained public key — plus the commit's
+*claimed* author. The gate mints a short-lived Ed25519 key at spin-up, holds the
+private half in the sidecar `ssh-agent`, and forwards only `SSH_AUTH_SOCK` into
+the bottle. The gate rejects any commit it forwards that is not signed by the
+activation key; separately, the **control plane** independently recomputes each
+commit's object ID and verifies its signature before recording attribution — it
+never trusts a SHA, key, or verdict asserted by the gate.
+
+This PRD deliberately does **not** enforce or vouch author/committer identity.
+Author/committer name/email are recorded as claims carried inside the signed
+object; making the gate reject a mismatching author/committer is a possible
+future add (see **Non-goals** and **Deferred: identity enforcement**). Push
+capability stays exactly as PRD 0048 deploy keys; forge subuser accounts,
+provisioned API tokens, and forge-side status/"Verified" badges remain out of
+scope (a future "forge actors" PRD).
+
+Successor to:
+
+- **PRD 0027 (agent git identity, #94)** / **ADR 0002** — established that
+  `git-gate.user` name/email is *claimed, not vouched*. This PRD keeps that
+  posture: it adds signed **provenance** and a durable host record, not identity
+  enforcement.
+- **PRD 0048 (deploy-key provisioning, #169)** — the host-side mint-at-spin-up /
+  revoke-at-teardown lifecycle the signing key follows. Deploy keys are
+  unchanged.
+- **PRD 0070 (per-host orchestrator, #351)** — the orchestrator/control plane is
+  the sole owner of `bot-bottle.db`; audit verification and recording live
+  there, not in the data-plane gate (see **Trust boundary**).
+
+## The guarantee
+
+The crisp property this feature provides:
+
+> The **host-owned audit store** binds a set of commit bytes — whose Git object
+> ID the control plane **recomputes** itself — to **access to this activation's
+> signing key**, and binds that key to **control-plane-owned activation
+> metadata**: bottle, host, manifest, agent, activation interval, retained public
+> key. An agent may author and sign arbitrary commit contents, but it cannot make
+> that signature verify as a *different* activation, and it cannot choose the
+> activation metadata the control plane records. The commit's author/committer
+> identity is **recorded as a claim**, not enforced or vouched. The forge remains
+> only the repository transport/capability layer.
+
+What this does and does not prove (issue #423, comments #5554 / #5607 / #5608):
+
+- It proves **access to activation *Y*'s signing key**: whoever assembled these
+  commit bytes could sign with that key. Recomputing the object ID and verifying
+  the embedded signature binds the SHA to activation *Y*, and the control plane's
+  own records bind *Y*'s key to *Y*'s metadata.
+- It does **not** prove the commit was ever pushed, observed upstream, kept
+  (vs. later reverted or dropped), or produced by the *agent* rather than by any
+  other holder of the activation signing capability (the sidecar itself). The
+  store deliberately makes no claim about publication or sole-agent authorship
+  — the owner's requirement is attribution of *what manifest/agent/etc. was in
+  use when a commit was signed*, not proof of where the commit went (#5607).
+- It does **not** make author/committer identity cryptographically vouched. The
+  bottle chooses every byte sent through the forwarded agent, so a signature over
+  `author Mallory <mallory@example>` is just as valid. Those fields are a claim
+  carried inside the signed object and recorded as-is.
+- The binding is trustworthy because the **control plane** supplies the SHA (it
+  recomputes it), the public key, and the activation metadata from its own state
+  — never from a value the gateway asserts (see **Trust boundary**). The
+  residual, by design: anything that holds the activation signing capability can
+  produce commits that attribute to that activation. That is inherent to a
+  binding on *activation-key access*, not a defect.
+
+## Problem
+
+An agent runs on the developer's machine as a *subrole*, scoped down per role.
+Locally that is fine because the machine is single-tenant. The git history an
+agent produces, however, is a durable artifact that outlives the session and
+can be pushed to shared repositories, and today bot-bottle offers no
+tamper-evidence over it:
+
+- **No provenance.** Nothing ties a pushed commit to the bottle/activation that
+  actually produced it. `git-gate.user` name/email is forgeable and cosmetic
+  (ADR 0002); a commit could be produced anywhere.
+- **No durable, portable record.** There is no host-side ledger that says "SHA
+  *X* was produced by agent *A* in bottle *B* on host *H* during interval
+  *[t0,t1]*, signed by key *K*," independent of any forge and surviving key
+  rotation.
+
+## Goals / Success Criteria
+
+- **Per-activation signing key.** A fresh Ed25519 keypair is minted host-side at
+  each activation; the private half lives only in the sidecar `ssh-agent`, never
+  in the bottle. Only `SSH_AUTH_SOCK` crosses the boundary.
+- **Signed commits with no SHA divergence.** Commits produced in the bottle are
+  signed at commit time; the SHA the agent observes is the SHA that reaches the
+  upstream through the gate.
+- **Gate rejects unsigned commits.** Before the gate forwards a push, every
+  newly-introduced commit (those not already reachable from the advertised
+  upstream refs) must verify against the activation public key; a push with any
+  unsigned or wrong-key new commit is rejected, loudly, with the offending SHA.
+  This is a **signature** check only — no author/committer matching.
+- **Control-plane-owned attribution.** The orchestrator/control plane (sole
+  owner of `bot-bottle.db`, PRD 0070) recomputes each commit's object ID from the
+  bytes, verifies the embedded signature against the activation public key it
+  holds, and attaches activation metadata from its own state — accepting no SHA,
+  key, verdict, or metadata asserted by the gateway. No upstream fetch is
+  required.
+- **Host is the source of truth.** The audit record binds each recomputed SHA to
+  the bottle, host, manifest, agent, activation interval, and retained public
+  key, and records the commit's claimed author/committer.
+- **Verifiable after teardown.** The audit record retains the **full public
+  key, fingerprint, principal, and validity interval** — enough to regenerate an
+  allowed-signers file and run `git verify-commit` long after the activation
+  ends and the key is gone.
+- **Reprovision-per-activation, fail-loud teardown.** The signing key is minted
+  once per activation (persists across restarts within that activation) and
+  discarded at teardown; deploy-key revocation continues to follow PRD 0048's
+  fail-loud discipline.
+- **Push capability unchanged.** Forge access remains PRD 0048 deploy keys; no
+  new forge API dependency beyond 0048's existing deploy-key registration.
+
+## Non-goals
+
+- **Author/committer enforcement.** Explicitly out of scope for this PRD (issue
+  #423, comment #5590). The gate does not reject a commit for carrying a foreign
+  author or committer; those fields are recorded as claims. We rely on the
+  cross-forge audit store of signed commits and the authors recorded there. See
+  **Deferred: identity enforcement** for what a future add would look like.
+- **Cryptographically-vouched author identity.** Not claimed — see **The
+  guarantee**.
+- **Forge subuser accounts / provisioned API tokens / PAT minting.** Dropped.
+  Gitea's `POST /users/:name/tokens` requires Basic Auth *as the target user*
+  (an admin PAT cannot mint one for another user; the only server-side path is
+  the `gitea admin user generate-access-token` CLI), so a token-minting
+  bootstrap is a design in its own right (issue #423, comments #5518 / #5554).
+  This PRD needs no subrole API token, so that bootstrap problem does not arise.
+- **Forge-side attribution surfaces.** No commit-status badges, no forge
+  "Verified" badge. The latter is doubly unsuitable: it renders dynamically
+  against a *currently registered* key (so it would lie the moment a
+  reprovisioned key is revoked), and on Gitea registering a signing key also
+  grants push. Attribution lives in the host record and local `git
+  verify-commit`, not the forge.
+- **Non-Gitea forges, dashboard UI for orphan cleanup, mid-session rotation,
+  dirty-teardown reconciliation.** As before; a separate cleanup/sync pass
+  handles orphans left by a crash or discarded snapshot.
+
+## Scope narrowing
+
+This PRD started as "forge subroles" (forge subuser accounts + provisioned API
+tokens + optional forge status posting + signing). Review (issue #423, comments
+#5518 → #5590) narrowed it in two steps:
+
+1. **Dropped the forge-account and API-token machinery** (#5518 → #5556):
+   the PAT bootstrap is not implementable as sketched (Basic-Auth-as-target-user
+   constraint); the signature never vouched the author anyway; and making the
+   host audit store the portable source of truth is a cleaner boundary that
+   removes the forge-specific token lifecycle and commit-status dependence.
+2. **Dropped author/committer enforcement** (#5590): rely on the audit store of
+   signed commits and the authors recorded there; gate enforcement of the
+   identity fields is a possible future add, not part of this slice.
+
+What remains is the core that stands on its own: **signed commits + a
+host-owned, independently-verified audit record.** Forge *actors* (a per-bottle
+account that comments/opens PRs) and *identity enforcement* (the gate rejecting a
+foreign author/committer) are each candidate future PRDs.
+
+## Design
+
+### Trust boundary (control plane vs data plane)
+
+git-gate is the **data plane**: it parses hostile bytes from inside the bottle
+and forwards pushes. The orchestrator is the **control plane** and, per PRD
+0070, is the sole owner of `bot-bottle.db`. These are different trust boundaries,
+and the audit record must be anchored in the control plane:
+
+- The gate performs a **synchronous pre-forward signature check** (below) and
+  can reject a push before it reaches the upstream. This is a data-plane gate on
+  what leaves the bottle, not the audit binding.
+- The **control plane** takes the commit bytes to attribute (gateway-delivered
+  opaque bytes are fine), **recomputes the Git object ID**, **verifies the
+  embedded signature** against the activation public key it minted and holds, and
+  writes `attributed_commit` attaching metadata from its own state. It accepts
+  **no** gateway-supplied `verified` flag, claimed SHA, public key, or activation
+  identity.
+
+The precise trust statement (issue #423, review by didericis-codex on d8362ec,
+resolved in #5608): the row binds *these commit bytes / this recomputed SHA* to
+*access to this activation's signing key*, and the control plane binds that key
+to the recorded activation metadata. It does **not** assert forge observation or
+that only the agent (not the signing sidecar) authored the commit — so this PRD
+does **not** claim a compromised gateway cannot obtain an attribution row.
+Because the sidecar holds the activation signing capability, a compromised
+gateway *can* assemble and sign a commit and have it attributed to that
+activation; what it cannot do is make the signature verify as a *different*
+activation or choose the metadata the control plane records. That residual is
+acceptable under the intended guarantee (#5607) and is why the guarantee is
+worded as activation-key access, not agent-only authorship or upstream
+publication. The gate therefore cannot stand in for host-side verification: the
+control plane recomputes the object ID and verifies the signature itself rather
+than trusting the gate's word.
+
+### Identity model
+
+Per **bottled agent** (agent definition ∘ sealed bottle), realized per
+activation:
+
+| Part | Value | Source | Role |
+|------|-------|--------|------|
+| Signing key | one Ed25519 keypair | minted host-side per activation | signs every commit; private half sidecar-only; the anchor of provenance |
+| Author/committer | name + email | `git-gate.user` (PRD 0027 overlay) | written into commits and **recorded** as a claim; **not** enforced |
+
+### Manifest surface
+
+No new top-level keys and no `git-forge`/`forge-accounts` blocks. A single
+opt-in flag under the existing `git-gate` key turns on per-activation signing;
+`git-gate.user` (PRD 0027) supplies the author string as today.
+
+```yaml
+git-gate:
+  user:                          # PRD 0027 — author string; recorded, not enforced
+    name: didericis-claude
+    email: eric+claude@dideric.is
+  signing:
+    enabled: true                # NEW — opt-in per-activation signing + audit
+  repos:
+    bot-bottle:
+      url: ssh://git@100.78.141.42:30009/didericis/bot-bottle.git
+      provisioned_key:           # PRD 0048 — push capability, UNCHANGED
+        provider: gitea
+        token_env: GITEA_DEPLOY_TOKEN
+      host_key: "ssh-ed25519 AAAA..."
+```
+
+- `git-gate.signing.enabled: true` opts a bottle in. Without it, behavior is
+  exactly as today. There is **no `enforce` sub-key** — this PRD does not enforce
+  identity fields, so no knob is needed (and a knob that weakened a guarantee
+  was flagged as a contradiction in review).
+- `git-gate.signing` is **bottle-only** (home-only policy), rejected at the
+  agent level with a clear pointer. `git-gate.user` keeps its PRD 0027
+  agent-overlay semantics.
+
+### Signing: sign at commit time via a forwarded ssh-agent
+
+The reason SHAs never diverge:
+
+- The **sidecar** (the git-gate trust boundary) runs an `ssh-agent` holding the
+  short-lived signing private key.
+- **Only `SSH_AUTH_SOCK`** is forwarded into the bottle — a bounded signing
+  capability, not the key.
+- The provisioner writes the bottle `.gitconfig`:
+
+  ```ini
+  [commit]
+      gpgsign = true
+  [gpg]
+      format = ssh
+  [user]
+      name = didericis-claude
+      email = eric+claude@dideric.is
+      signingkey = ssh-ed25519 AAAA...   # activation signing PUBLIC key
+  ```
+
+- `git commit` asks the forwarded agent to sign; the signature is embedded at
+  object creation, so the agent-space SHA equals the pushed SHA. No transcoder,
+  no SHA translation table.
+
+### Gate pre-forward signature check (data plane)
+
+The gate already fetches from upstream before every `upload-pack` and mirrors
+bidirectionally (PRD 0008). When `git-gate.signing.enabled` is set, after
+gitleaks and before forwarding a push upstream:
+
+1. **Compute the newly-introduced set.** Commits reachable from the pushed ref
+   tips but **not** reachable from any ref already advertised by the upstream
+   (which the gate knows because it fetches upstream first) — equivalent to
+   `git rev-list <new-tips> --not <all-known-upstream-refs>`. This excludes
+   pulled/merged existing history; a merge commit the bottle creates is itself
+   new and is checked, its already-upstream ancestors are not.
+2. **Verify each new commit's signature** against the activation public key. A
+   commit that is unsigned or signed by any other key causes the push to be
+   **rejected** with the offending SHA.
+3. No author/committer matching is performed.
+
+This is a synchronous safety gate on what leaves the bottle; it is not the audit
+record.
+
+### Control-plane verification & recording
+
+For each commit to attribute (the gate hands the control plane the commit bytes;
+opaque gateway-delivered bytes are acceptable because nothing the gateway *says*
+about them is trusted), the orchestrator/control plane:
+
+1. **Recomputes the Git object ID** from the bytes itself. The stored `sha` is
+   this recomputed value, never a SHA the gateway claims.
+2. **Verifies the embedded signature** against the activation public key it
+   minted and holds for that activation (via a generated allowed-signers file) —
+   ignoring any `verified` flag, key, or activation identity supplied by the
+   gateway.
+3. Writes `attributed_commit` only for bytes that pass, stamping the activation
+   metadata (bottle/manifest/agent/host/interval) from its **own** state — not
+   from anything the gateway provides — and recording the commit's claimed
+   author/committer.
+
+No upstream fetch is required: the guarantee is a byte↔activation-key binding, so
+the object does not need to come from the forge (issue #423, #5608). Bytes that
+do not verify against the activation key are **not** recorded as attributed (they
+may be logged as an anomaly instead).
+
+### Audit trail
+
+The host SQLite store (PRD 0067, `~/.bot-bottle/bot-bottle.db`, owned by the
+control plane per PRD 0070) records the signing-key lifecycle and per-commit
+attribution. Retention is the **full public key, fingerprint, principal, and
+validity interval** — enough to regenerate an allowed-signers file and verify
+commits after teardown (issue #423, comment #5554, resolution 3). Never any
+private key material.
+
+```sql
+CREATE TABLE bottled_agent_activation (
+    bottled_agent_slug TEXT NOT NULL,
+    activation_id      TEXT NOT NULL,     -- one per activation cycle
+    host              TEXT NOT NULL,
+    manifest_digest   TEXT NOT NULL,      -- ties the record to the sealed manifest
+    agent             TEXT NOT NULL,
+    signing_pubkey    TEXT NOT NULL,      -- full ssh-ed25519 public key (for verify-commit)
+    signing_fpr       TEXT NOT NULL,      -- SHA256:... fingerprint (stable handle)
+    principal         TEXT NOT NULL,      -- allowed-signers principal, e.g. the author email
+    valid_from        TEXT NOT NULL,
+    valid_until       TEXT,               -- NULL while active; set at teardown
+    status            TEXT NOT NULL,      -- active | retired
+    PRIMARY KEY (bottled_agent_slug, activation_id)
+);
+
+CREATE TABLE attributed_commit (
+    sha                TEXT NOT NULL,      -- control-plane-RECOMPUTED object ID, not gateway-claimed
+    bottled_agent_slug TEXT NOT NULL,
+    activation_id      TEXT NOT NULL,
+    repo               TEXT NOT NULL,
+    author_name        TEXT NOT NULL,     -- CLAIMED, recorded as-is (not enforced)
+    author_email       TEXT NOT NULL,     -- CLAIMED
+    committer_name     TEXT NOT NULL,     -- CLAIMED
+    committer_email    TEXT NOT NULL,     -- CLAIMED
+    observed_at        TEXT NOT NULL,
+    PRIMARY KEY (sha, repo)
+);
+```
+
+Verification/allowed-signers generation is a stated part of the design: for a
+given SHA, join `attributed_commit → bottled_agent_activation`, emit
+`<principal> <signing_pubkey>` to a temporary allowed-signers file, and
+`git verify-commit` (or `ssh-keygen -Y verify`) against it. The
+`(pubkey, principal, valid_from/until)` tuple is exactly what that requires. The
+recorded author/committer columns are the *claim*; a consumer that wants to know
+"who says they wrote this" reads them, understanding they are unenforced.
+
+### Credential lifecycle
+
+Follows PRD 0048, minus the API-token kind (dropped):
+
+- **Activation:** mint a fresh Ed25519 signing keypair; load the private half
+  into the sidecar `ssh-agent`; write the public half into `.gitconfig` and the
+  `bottled_agent_activation` row (`active`, `valid_from` set). Deploy keys are
+  provisioned exactly as PRD 0048. Minting is **per activation** (a restart
+  re-attaches the same key; a new activation mints a new key and retires the old
+  row), so frozen snapshots don't accumulate live keys.
+- **Teardown (fail-loud):** revoke provisioned deploy keys via the forge API
+  (0048); discard the signing key from the sidecar agent and set the activation
+  row to `retired` with `valid_until`. The signing key was never on the forge,
+  so there is nothing to revoke there — only the local retire. Deploy-key
+  revocation failure halts teardown (0048); 404 = already-gone = success.
+- **Dirty teardown** is assumed handled; a separate cleanup/sync pass reconciles
+  orphaned deploy keys.
+
+## Deferred: identity enforcement
+
+If a future PRD wants the gate to *enforce* that new commits carry the manifest
+identity, the natural shape is: extend the gate pre-forward check to also require
+each new commit's author **and** committer name/email to equal `git-gate.user`,
+rejecting mismatches — with the same control-plane re-verification before
+recording. This is deliberately left out now (issue #423, comment #5590); it is
+noted so the door stays open and the current schema (which records the claimed
+author/committer) already carries what such a check would compare against. Note
+that even then the property would be gate-*enforced*, not signature-*vouched*; a
+validating signing broker in front of the key would be required for the latter.
+
+## Implementation chunks
+
+1. **This PRD.** Sets the (narrowed) design.
+2. **Manifest surface.** Add `git-gate.signing` (bottle-only; `enabled` only);
+   reject it at the agent level. Unit tests for parse/validation and the
+   agent-level rejection.
+3. **Signing pipeline.** Sidecar `ssh-agent` provisioning; forward
+   `SSH_AUTH_SOCK` into the bottle across docker, smolmachines, macOS-container,
+   and firecracker backends; emit the `commit.gpgsign` / `gpg.format=ssh` /
+   `user.signingkey` gitconfig. Integration test: a bottle commit is
+   `verify-commit`-valid and its SHA is unchanged through the gate; the private
+   key is absent from the bottle.
+4. **Gate pre-forward signature check.** Compute the newly-introduced set
+   (excluding upstream-reachable commits), verify each against the activation
+   key, reject unsigned/wrong-key with the offending SHA. Tests: unsigned
+   rejected; wrong-key rejected; pulled/merged upstream history passes; an
+   all-signed push succeeds. A foreign-author commit that is correctly signed
+   **passes the gate** (identity is not enforced here).
+5. **Control-plane verification + audit.** `bottled_agent_activation` /
+   `attributed_commit` tables (PRD 0067 store, control-plane-owned per PRD 0070);
+   the control plane recomputes each commit's object ID and verifies the
+   signature before writing a row; retain full pubkey + fingerprint + principal +
+   validity interval; record claimed author/committer; allowed-signers generation
+   + a post-teardown `verify-commit` helper. Tests: a gateway-claimed SHA/key/
+   verdict is ignored — the row's `sha` is the recomputed ID and bytes not signed
+   by the activation key produce **no** row.
+6. **Docs.** Glossary entry ("per-bottle signed commits"); README manifest
+   section; ADR note that signing-enabled bottles gain signed *provenance* and a
+   host-owned audit record while authorship stays *claimed* (ADR 0002 unchanged).
+
+## Testing strategy
+
+- **Unit (must):** `git-gate.signing` parse/validation; agent-level `signing`
+  rejection.
+- **Integration — signing (must):** end-to-end signed commit verifies with
+  `git verify-commit`; SHA observed in the bottle equals the SHA upstream; the
+  private key is absent from the bottle.
+- **Integration — gate check (must):** unsigned rejected; wrong-key rejected;
+  the upstream-reachable exclusion (pull + merge human history and push a signed
+  merge); a correctly-signed foreign-author commit **passes** (no identity
+  enforcement); a clean all-signed push succeeds.
+- **Control plane (must):** the control plane recomputes the object ID and
+  records a row for bytes genuinely signed by the activation key; a gateway-
+  supplied SHA/key/verdict is ignored (the stored `sha` is the recomputed value);
+  bytes signed by a foreign/invalid key produce **no** row.
+- **Lifecycle:** activation mints the key and writes an `active` row; teardown
+  retires it (`valid_until`) and revokes deploy keys fail-loud; a restart
+  re-attaches the same key (no new row); a fresh activation mints a new key and
+  retires the old.
+- **Post-teardown verification:** regenerate the allowed-signers file from a
+  `retired` row and confirm `verify-commit` still succeeds for an attributed SHA.
+
+## Resolved: control-plane transport
+
+Raised in review and **resolved** (issue #423, #5608): the commit object does not
+need to come from the forge, and reading the gateway-owned mirror is no stronger
+than accepting gateway-delivered bytes — both are fabricatable, and neither
+matters because the control plane trusts nothing the gateway *asserts*. The
+transport is therefore: the gate hands the control plane the raw commit bytes,
+the control plane **recomputes the object ID** and **verifies the signature**
+against the activation key, and stamps its own activation metadata. No upstream
+fetch. This is exactly what makes the byte↔activation-key binding sound
+regardless of transport.
+
+## Open questions
+
+- **Where the gate check slots into PRD 0008 ordering.** Modeled as a
+  pre-forward step after gitleaks; confirm it composes with the existing
+  access-hook / mirror ordering rather than needing a separate hook.

tests/unit/test_docker_orchestrator.py

@@ -19,7 +19,9 @@ _ORCH = "bot_bottle.backend.docker.orchestrator"
 _RUN = f"{_ORCH}.run_docker"
 _SLEEP = f"{_ORCH}.time.sleep"
 _MONOTONIC = f"{_ORCH}.time.monotonic"
-_TOKEN = f"{_ORCH}.host_orchestrator_token"
+# The signing key is read through the shared provisioning contract (#476); patch
+# its host-canonical key file read to keep it off the real host file.
+_TOKEN = "bot_bottle.trust_domain.host_signing_key"
 # The ABC's is_healthy probes /health via urllib in the lifecycle module.
 _URLOPEN = "bot_bottle.orchestrator.lifecycle.urllib.request.urlopen"
 

tests/unit/test_firecracker_orchestrator.py

@@ -44,7 +44,7 @@ class TestEnsureRunning(unittest.TestCase):
         vm = infra_vm.InfraVm(guest_ip="10.243.255.1", private_key=Path("/k"), vm=MagicMock())
         with patch.object(infra_vm, "boot_vm", return_value=vm) as boot, \
                 patch.object(infra_vm, "push_secret") as push, \
-                patch(f"{_ORCH}.host_orchestrator_token", return_value="host-key"), \
+                patch("bot_bottle.trust_domain.host_signing_key", return_value="host-key"), \
                 patch.object(orch, "is_running", return_value=False), \
                 patch.object(orch, "_ensure_registry_volume", return_value=Path("/reg")), \
                 patch.object(orch, "_wait_for_health"):

tests/unit/test_macos_orchestrator.py

@@ -33,7 +33,7 @@ class TestMacosOrchestratorRun(unittest.TestCase):
     def _run(self) -> list[str]:
         run = Mock(return_value=_ok())
         with patch(f"{_ORCH}.container_mod") as mod, \
-                patch(f"{_ORCH}.host_orchestrator_token", return_value="k"):
+                patch("bot_bottle.trust_domain.host_signing_key", return_value="k"):
             mod.dns_server.return_value = "1.1.1.1"
             mod.bind_mount_spec.side_effect = _spec
             mod.run_container_argv = run
@@ -65,7 +65,7 @@ class TestMacosOrchestratorRun(unittest.TestCase):
 
     def test_start_failure_raises(self) -> None:
         with patch(f"{_ORCH}.container_mod") as mod, \
-                patch(f"{_ORCH}.host_orchestrator_token", return_value="k"):
+                patch("bot_bottle.trust_domain.host_signing_key", return_value="k"):
             mod.dns_server.return_value = "1.1.1.1"
             mod.run_container_argv = Mock(return_value=_fail())
             with self.assertRaises(OrchestratorStartError):

tests/unit/test_orchestrator_auth.py

@@ -82,5 +82,26 @@ class TestMintVerify(unittest.TestCase):
             mint(ROLE_GATEWAY, "")
 
 
+class TestCustomRoleSet(unittest.TestCase):
+    """The `roles=` seam a trust domain other than the control plane uses (#476):
+    mint/verify are scoped to the passed role set, not the module default."""
+
+    _ROLES = frozenset({"host"})
+
+    def test_round_trips_a_role_in_the_custom_set(self) -> None:
+        tok = mint("host", _KEY, roles=self._ROLES)
+        self.assertEqual("host", verify(tok, _KEY, roles=self._ROLES))
+
+    def test_mint_rejects_a_role_outside_the_custom_set(self) -> None:
+        with self.assertRaises(ValueError):
+            mint(ROLE_CLI, _KEY, roles=self._ROLES)
+
+    def test_verify_rejects_a_role_outside_the_verifiers_set(self) -> None:
+        # A validly signed token whose role isn't in the verifier's set fails —
+        # this is what keeps one domain's key from asserting another's role.
+        tok = mint(ROLE_CLI, _KEY)  # a control-plane `cli` token
+        self.assertIsNone(verify(tok, _KEY, roles=self._ROLES))
+
+
 if __name__ == "__main__":
     unittest.main()

tests/unit/test_orchestrator_client.py

@@ -20,13 +20,15 @@ _URLOPEN = "bot_bottle.orchestrator.client.urllib.request.urlopen"
 
 class TestHostAuthToken(unittest.TestCase):
     def test_mints_a_cli_token_from_the_host_key(self) -> None:
-        with patch("bot_bottle.orchestrator.client.host_orchestrator_token",
+        # The CLI mints its `cli` token from the control-plane trust domain's
+        # host-canonical key (#476) — patch the key file read underneath it.
+        with patch("bot_bottle.trust_domain.host_signing_key",
                    return_value="signing-key"):
             tok = _host_auth_token()
         self.assertEqual(ROLE_CLI, verify(tok, "signing-key"))
 
     def test_returns_empty_when_key_unreadable(self) -> None:
-        with patch("bot_bottle.orchestrator.client.host_orchestrator_token",
+        with patch("bot_bottle.trust_domain.host_signing_key",
                    side_effect=OSError("no host root")):
             self.assertEqual("", _host_auth_token())
 

tests/unit/test_trust_domain.py

@@ -0,0 +1,105 @@
+"""Unit: trust domains + the shared control-plane provisioning contract (#476)."""
+
+from __future__ import annotations
+
+import unittest
+from unittest.mock import patch
+
+from bot_bottle import orchestrator_auth
+from bot_bottle.orchestrator_auth import ROLE_CLI, ROLE_GATEWAY
+from bot_bottle.trust_domain import (
+    CONTROL_PLANE,
+    ControlPlaneProvisioning,
+    ProvisioningError,
+    TrustDomain,
+)
+
+# A second, unrelated domain — the shape #468's host controller would take: its
+# own key file, its own role, its own env vars. Distinct from CONTROL_PLANE.
+_HOST_CTRL = TrustDomain(
+    name="host-controller",
+    key_filename="host-controller-token",
+    roles=frozenset({"host"}),
+    key_env="BOT_BOTTLE_HOST_CONTROLLER_TOKEN",
+    token_env="BOT_BOTTLE_HOST_CONTROLLER_JWT",
+)
+
+
+class TestTrustDomainMintVerify(unittest.TestCase):
+    def test_mint_verify_round_trips_within_a_domain(self) -> None:
+        with patch("bot_bottle.trust_domain.host_signing_key", return_value="k"):
+            tok = CONTROL_PLANE.mint(ROLE_GATEWAY)
+        self.assertEqual(ROLE_GATEWAY, CONTROL_PLANE.verify(tok, "k"))
+
+    def test_mint_rejects_a_role_outside_the_domain(self) -> None:
+        # `host` is a valid role in _HOST_CTRL but not in the control plane —
+        # the control-plane key must refuse to mint it.
+        with patch("bot_bottle.trust_domain.host_signing_key", return_value="k"):
+            with self.assertRaises(ValueError):
+                CONTROL_PLANE.mint("host")
+
+    def test_a_custom_role_set_verifies_its_own_role(self) -> None:
+        with patch("bot_bottle.trust_domain.host_signing_key", return_value="k"):
+            tok = _HOST_CTRL.mint("host")
+        self.assertEqual("host", _HOST_CTRL.verify(tok, "k"))
+
+    def test_key_from_env_reads_the_domains_env_var(self) -> None:
+        self.assertEqual(
+            "secret", CONTROL_PLANE.key_from_env({CONTROL_PLANE.key_env: " secret "}))
+        self.assertEqual("", CONTROL_PLANE.key_from_env({}))
+
+
+class TestDomainBoundary(unittest.TestCase):
+    """The #476/#468 invariant: two domains, two keys, two role sets — one
+    domain's key can neither mint nor verify the other's tokens."""
+
+    def test_a_control_plane_token_does_not_verify_under_another_domains_key(
+        self,
+    ) -> None:
+        # Even with an IDENTICAL underlying key, a `cli` token minted under the
+        # control-plane domain must not verify as a role in the host-controller
+        # domain — the role isn't in that domain's set.
+        cli_tok = orchestrator_auth.mint(ROLE_CLI, "shared-bytes")
+        self.assertIsNone(_HOST_CTRL.verify(cli_tok, "shared-bytes"))
+
+    def test_distinct_keys_do_not_cross_verify(self) -> None:
+        # The realistic case: distinct host-canonical keys per domain. A token
+        # signed by one key never verifies under the other.
+        host_tok = orchestrator_auth.mint(
+            "host", "host-ctrl-key", roles=_HOST_CTRL.roles)
+        self.assertIsNone(_HOST_CTRL.verify(host_tok, "control-plane-key"))
+        self.assertEqual("host", _HOST_CTRL.verify(host_tok, "host-ctrl-key"))
+
+
+class TestControlPlaneProvisioning(unittest.TestCase):
+    def test_orchestrator_key_returns_the_canonical_key(self) -> None:
+        prov = ControlPlaneProvisioning()
+        with patch("bot_bottle.trust_domain.host_signing_key", return_value="key"):
+            self.assertEqual("key", prov.orchestrator_key())
+
+    def test_orchestrator_key_fail_closes_when_empty(self) -> None:
+        # Invariant 4: the orchestrator must never start without a key — it would
+        # run OPEN and grant every caller that reaches it full `cli`. There is no
+        # topology opt-out: a separate host does not stop the gateway (or any
+        # other caller) from reaching the control-plane listener.
+        prov = ControlPlaneProvisioning()
+        with patch("bot_bottle.trust_domain.host_signing_key", return_value=""):
+            with self.assertRaises(ProvisioningError):
+                prov.orchestrator_key()
+
+    def test_gateway_token_is_a_verifiable_gateway_role_token(self) -> None:
+        prov = ControlPlaneProvisioning()
+        with patch("bot_bottle.trust_domain.host_signing_key", return_value="k"):
+            tok = prov.gateway_token()
+        self.assertEqual(ROLE_GATEWAY, CONTROL_PLANE.verify(tok, "k"))
+
+    def test_gateway_token_cannot_be_reused_as_cli(self) -> None:
+        # The data plane's token is `gateway`-scoped: it never carries `cli`.
+        prov = ControlPlaneProvisioning()
+        with patch("bot_bottle.trust_domain.host_signing_key", return_value="k"):
+            tok = prov.gateway_token()
+        self.assertNotEqual(ROLE_CLI, CONTROL_PLANE.verify(tok, "k"))
+
+
+if __name__ == "__main__":
+    unittest.main()