claude_bottle/backend/__init__.py

@@ -204,24 +204,35 @@ class BottleBackend(ABC, Generic[PlanT, CleanupT]):
         """Build/run the bottle and yield a handle; tear down on exit."""
 
     def provision(self, plan: PlanT, target: str) -> str | None:
-        """Copy host-side files (prompt, skills, SSH keys, .git) into
-        the running bottle. Called from `launch` after the container/
-        machine is up. `target` identifies the running instance in
-        backend-specific terms (Docker: resolved container name; fly:
-        machine id). Returns the in-container prompt path if a prompt
-        was provisioned, else None — the Bottle handle uses it to
-        decide whether to add --append-system-prompt-file to claude's
-        argv.
+        """Copy host-side files (CA cert, prompt, skills, SSH keys,
+        .git) into the running bottle. Called from `launch` after the
+        container/machine is up. `target` identifies the running
+        instance in backend-specific terms (Docker: resolved container
+        name; fly: machine id). Returns the in-container prompt path
+        if a prompt was provisioned, else None — the Bottle handle
+        uses it to decide whether to add --append-system-prompt-file
+        to claude's argv.
 
-        Default orchestration: prompt → skills → ssh → git. Subclasses
-        typically don't override this; they implement the four
-        sub-methods below."""
+        Default orchestration: ca → prompt → skills → ssh → git.
+        CA goes first because it changes how the agent process trusts
+        the network; the rest don't depend on it but the order keeps
+        trust setup adjacent to the launch step. Subclasses typically
+        don't override this; they implement the sub-methods below."""
+        self.provision_ca(plan, target)
         prompt_path = self.provision_prompt(plan, target)
         self.provision_skills(plan, target)
         self.provision_ssh(plan, target)
         self.provision_git(plan, target)
         return prompt_path
 
+    def provision_ca(self, plan: PlanT, target: str) -> None:
+        """Install the egress-proxy's CA into the running bottle's
+        trust store. Default impl is a no-op so backends that don't
+        yet support TLS interception (every backend except Docker
+        today) aren't forced to implement it. The Docker backend
+        overrides to extract mitmproxy's CA and run
+        `update-ca-certificates` inside the agent container."""
+
     @abstractmethod
     def provision_prompt(self, plan: PlanT, target: str) -> str | None:
         """Copy the prompt file into the running bottle. Returns the

claude_bottle/backend/docker/backend.py

@@ -23,7 +23,9 @@ from . import prepare as _prepare
 from .bottle import DockerBottle
 from .bottle_cleanup_plan import DockerBottleCleanupPlan
 from .bottle_plan import DockerBottlePlan
+from .mitmproxy import DockerMitmproxyProxy
 from .pipelock import DockerPipelockProxy
+from .provision import ca as _ca
 from .provision import git as _git
 from .provision import prompt as _prompt
 from .provision import skills as _skills
@@ -38,15 +40,23 @@ class DockerBottleBackend(BottleBackend["DockerBottlePlan", "DockerBottleCleanup
 
     def __init__(self) -> None:
         self._proxy = DockerPipelockProxy()
+        self._mitm = DockerMitmproxyProxy()
 
     def _resolve_plan(self, spec: BottleSpec, *, stage_dir: Path) -> DockerBottlePlan:
-        return _prepare.resolve_plan(spec, stage_dir=stage_dir, proxy=self._proxy)
+        return _prepare.resolve_plan(
+            spec, stage_dir=stage_dir, proxy=self._proxy, mitm=self._mitm,
+        )
 
     @contextmanager
     def launch(self, plan: DockerBottlePlan) -> Generator[DockerBottle, None, None]:
-        with _launch.launch(plan, proxy=self._proxy, provision=self.provision) as bottle:
+        with _launch.launch(
+            plan, proxy=self._proxy, mitm=self._mitm, provision=self.provision,
+        ) as bottle:
             yield bottle
 
+    def provision_ca(self, plan: DockerBottlePlan, target: str) -> None:
+        _ca.provision_ca(plan, target)
+
     def provision_prompt(self, plan: DockerBottlePlan, target: str) -> str | None:
         return _prompt.provision_prompt(plan, target)
 

claude_bottle/backend/docker/bottle_plan.py

@@ -13,6 +13,7 @@ from pathlib import Path
 
 from ...log import info
 from ...manifest import Agent, Bottle
+from ...mitmproxy import MitmproxyProxyPlan
 from ...pipelock import PipelockProxyPlan, pipelock_effective_allowlist
 from .. import BottlePlan
 
@@ -49,6 +50,7 @@ class DockerBottlePlan(BottlePlan):
     forwarded_env: dict[str, str] = field(repr=False)
     prompt_file: Path
     proxy_plan: PipelockProxyPlan
+    mitmproxy_plan: MitmproxyProxyPlan
     allowlist_summary: str
     use_runsc: bool
 
@@ -93,6 +95,7 @@ class DockerBottlePlan(BottlePlan):
         else:
             info("  ssh hosts     : (none)")
         info(f"  egress        : {self.allowlist_summary}")
+        info("  tls intercept : mitmproxy (per-bottle ephemeral CA, generated at launch)")
         info(
             f"prompt          : {len(v.agent.prompt)} chars; "
             f"first line: {v.prompt_first_line or '(empty)'}"
@@ -117,6 +120,14 @@ class DockerBottlePlan(BottlePlan):
             "egress": {
                 "host_count": len(hosts),
                 "hosts": hosts,
+                # Reserved for PRD 0005: TLS interception via mitmproxy.
+                # ca_fingerprint is always null at dry-run because the
+                # CA is generated by the sidecar at launch time. Real
+                # launches print the fingerprint to stderr.
+                "mitm": {
+                    "enabled": True,
+                    "ca_fingerprint": None,
+                },
             },
             "prompt": {
                 "length": len(v.agent.prompt),

claude_bottle/backend/docker/launch.py

@@ -22,8 +22,15 @@ from . import network as network_mod
 from . import util as docker_mod
 from .bottle import DockerBottle
 from .bottle_plan import DockerBottlePlan
+from .mitmproxy import DockerMitmproxyProxy, mitmproxy_proxy_url
 from .pipelock import DockerPipelockProxy, pipelock_proxy_url
 
+# Path inside the agent container where the mitmproxy CA cert lives
+# after provision_ca runs. Exported as a module-level constant so
+# both the agent's docker-run env trio and the provisioner agree.
+AGENT_CA_PATH = "/usr/local/share/ca-certificates/claude-bottle-mitm.crt"
+AGENT_CA_BUNDLE = "/etc/ssl/certs/ca-certificates.crt"
+
 
 # Where the repo root lives, for `docker build` context. Computed once.
 _REPO_DIR = str(Path(__file__).resolve().parent.parent.parent.parent)
@@ -34,6 +41,7 @@ def launch(
     plan: DockerBottlePlan,
     *,
     proxy: DockerPipelockProxy,
+    mitm: DockerMitmproxyProxy,
     provision: Callable[[DockerBottlePlan, str], str | None],
 ) -> Generator[DockerBottle, None, None]:
     """Build, launch, and provision a Docker bottle. Teardown on exit.
@@ -71,6 +79,17 @@ def launch(
         pipelock_name = proxy.start(proxy_plan)
         stack.callback(proxy.stop, pipelock_name)
 
+        # mitmproxy sits in front of pipelock on the agent's egress
+        # path. mitmproxy's `addon.py` reaches pipelock via the
+        # service-name URL we hand it here.
+        mitm_plan = dataclasses.replace(
+            plan.mitmproxy_plan,
+            internal_network=internal_network,
+            egress_network=egress_network,
+        )
+        mitm_name = mitm.start(mitm_plan, pipelock_url=pipelock_proxy_url(plan.slug))
+        stack.callback(mitm.stop, mitm_name)
+
         container = _run_agent_container(plan, internal_network)
         stack.callback(docker_mod.force_remove_container, container)
 
@@ -85,7 +104,10 @@ def _run_agent_container(plan: DockerBottlePlan, internal_network: str) -> str:
     """Build the `docker run` argv and execute it, handling name-
     conflict races by incrementing the suffix (unless the name was
     user-pinned). Returns the resolved container name."""
-    proxy_url = pipelock_proxy_url(plan.slug)
+    # Agent traffic routes through mitmproxy, not pipelock directly.
+    # mitmproxy decrypts and hands the plaintext to pipelock via its
+    # addon; pipelock is unchanged from PRD 0001.
+    proxy_url = mitmproxy_proxy_url(plan.slug)
     docker_args: list[str] = [
         "--rm", "-d",
         "--name", plan.container_name,
@@ -93,6 +115,16 @@ def _run_agent_container(plan: DockerBottlePlan, internal_network: str) -> str:
         "-e", f"HTTPS_PROXY={proxy_url}",
         "-e", f"HTTP_PROXY={proxy_url}",
         "-e", "NO_PROXY=localhost,127.0.0.1",
+        # CA trust trio for the agent process. Docker propagates
+        # run-time env into `docker exec`, so `claude` sees these
+        # without per-exec threading. NODE_EXTRA_CA_CERTS points at
+        # the cert file (Node appends it to its bundled roots);
+        # SSL_CERT_FILE / REQUESTS_CA_BUNDLE point at the system
+        # bundle that `update-ca-certificates` rebuilds in
+        # provision_ca.
+        "-e", f"NODE_EXTRA_CA_CERTS={AGENT_CA_PATH}",
+        "-e", f"SSL_CERT_FILE={AGENT_CA_BUNDLE}",
+        "-e", f"REQUESTS_CA_BUNDLE={AGENT_CA_BUNDLE}",
     ]
     if plan.use_runsc:
         docker_args.extend(["--runtime", "runsc"])

claude_bottle/backend/docker/mitmproxy.py

@@ -0,0 +1,178 @@
+"""DockerMitmproxyProxy — the Docker-specific lifecycle for the
+mitmproxy sidecar. Inherits the addon-bundling from MitmproxyProxy.
+
+The sidecar runs `mitmdump -s /addon/addon.py`, listens on
+MITMPROXY_PORT inside the per-bottle internal network, and generates
+its own ephemeral CA on first launch (extracted by provision_ca,
+installed into the agent's trust store)."""
+
+from __future__ import annotations
+
+import os
+import subprocess
+import time
+from pathlib import Path
+
+from ...log import die, info, warn
+from ...mitmproxy import MitmproxyProxy, MitmproxyProxyPlan
+
+
+# mitmproxy/mitmproxy:12.2.3 (mitmproxy v12 release line). The digest
+# is the multi-arch image index — pulls resolve to the right per-arch
+# child digest. Bumped deliberately; see PRD 0005.
+MITMPROXY_IMAGE = os.environ.get(
+    "CLAUDE_BOTTLE_MITMPROXY_IMAGE",
+    "mitmproxy/mitmproxy@sha256:00b77b5d8804c8ad18cb6caefbf9d5849e895e8986c5ce011f4ae30f4385962f",
+)
+
+# Listening port for mitmproxy's forward proxy (agent-facing).
+MITMPROXY_PORT = os.environ.get("CLAUDE_BOTTLE_MITMPROXY_PORT", "8080")
+
+# Path inside the sidecar where the addon is dropped by docker cp.
+MITMPROXY_ADDON_PATH = "/addon/addon.py"
+
+# Path inside the sidecar where mitmproxy generates its CA.
+_CA_PATH_IN_SIDECAR = "/home/mitmproxy/.mitmproxy/mitmproxy-ca-cert.pem"
+
+
+def mitmproxy_container_name(slug: str) -> str:
+    return f"claude-bottle-mitm-{slug}"
+
+
+def mitmproxy_proxy_url(slug: str) -> str:
+    return f"http://{mitmproxy_container_name(slug)}:{MITMPROXY_PORT}"
+
+
+class DockerMitmproxyProxy(MitmproxyProxy):
+    """Brings the mitmproxy sidecar up and down via Docker."""
+
+    def start(self, plan: MitmproxyProxyPlan, *, pipelock_url: str) -> str:
+        """Boot the mitmproxy sidecar:
+          1. `docker create` on the internal network with mitmdump
+             argv: `--listen-port <port> -s <addon path>` plus the
+             pipelock URL injected as an env var.
+          2. `docker cp` the vendored addon to the sidecar.
+          3. Attach to the per-agent egress network so mitmproxy
+             can reach real upstreams.
+          4. `docker start`.
+        Returns the container name (the proxy_target passed to .stop
+        and .extract_ca_cert)."""
+        name = mitmproxy_container_name(plan.slug)
+        if not plan.addon_src.is_file():
+            die(f"mitmproxy addon not found at {plan.addon_src}")
+
+        info(f"starting mitmproxy sidecar {name} on network {plan.internal_network}")
+
+        create_args = [
+            "docker", "create",
+            "--name", name,
+            "--network", plan.internal_network,
+            "-e", f"CLAUDE_BOTTLE_PIPELOCK_URL={pipelock_url}",
+            MITMPROXY_IMAGE,
+            "mitmdump",
+            "--listen-port", MITMPROXY_PORT,
+            "-s", MITMPROXY_ADDON_PATH,
+        ]
+        if subprocess.run(
+            create_args,
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+            check=False,
+        ).returncode != 0:
+            die(f"failed to create mitmproxy sidecar {name}")
+
+        cp_result = subprocess.run(
+            ["docker", "cp", str(plan.addon_src), f"{name}:{MITMPROXY_ADDON_PATH}"],
+            capture_output=True,
+            text=True,
+            check=False,
+        )
+        if cp_result.returncode != 0:
+            subprocess.run(
+                ["docker", "rm", "-f", name],
+                stdout=subprocess.DEVNULL,
+                stderr=subprocess.DEVNULL,
+                check=False,
+            )
+            die(f"failed to copy mitmproxy addon into {name}: {cp_result.stderr.strip()}")
+
+        if subprocess.run(
+            ["docker", "network", "connect", plan.egress_network, name],
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+            check=False,
+        ).returncode != 0:
+            subprocess.run(
+                ["docker", "rm", "-f", name],
+                stdout=subprocess.DEVNULL,
+                stderr=subprocess.DEVNULL,
+                check=False,
+            )
+            die(f"failed to attach mitmproxy sidecar {name} to egress "
+                f"network {plan.egress_network}")
+
+        if subprocess.run(
+            ["docker", "start", name],
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+            check=False,
+        ).returncode != 0:
+            subprocess.run(
+                ["docker", "rm", "-f", name],
+                stdout=subprocess.DEVNULL,
+                stderr=subprocess.DEVNULL,
+                check=False,
+            )
+            die(f"failed to start mitmproxy sidecar {name}")
+
+        return name
+
+    def stop(self, proxy_target: str) -> None:
+        """Idempotent: missing container is success. Mirrors
+        DockerPipelockProxy.stop."""
+        if subprocess.run(
+            ["docker", "inspect", proxy_target],
+            stdout=subprocess.DEVNULL,
+            stderr=subprocess.DEVNULL,
+            check=False,
+        ).returncode == 0:
+            if subprocess.run(
+                ["docker", "rm", "-f", proxy_target],
+                stdout=subprocess.DEVNULL,
+                stderr=subprocess.DEVNULL,
+                check=False,
+            ).returncode != 0:
+                warn(
+                    f"failed to remove mitmproxy sidecar {proxy_target}; "
+                    f"clean up with 'docker rm -f {proxy_target}'"
+                )
+
+    def extract_ca_cert(self, proxy_target: str, dest_path: Path) -> None:
+        """Poll the running sidecar for the CA cert (mitmproxy
+        generates it on first launch, typically <1s after start),
+        then `docker cp` the public half to `dest_path`. The private
+        key never leaves the container."""
+        deadline = time.monotonic() + 15
+        while time.monotonic() < deadline:
+            check = subprocess.run(
+                ["docker", "exec", proxy_target, "test", "-f", _CA_PATH_IN_SIDECAR],
+                stdout=subprocess.DEVNULL,
+                stderr=subprocess.DEVNULL,
+                check=False,
+            )
+            if check.returncode == 0:
+                break
+            time.sleep(0.5)
+        else:
+            die(f"mitmproxy CA cert did not appear at {_CA_PATH_IN_SIDECAR} "
+                f"after 15s — sidecar {proxy_target} may have failed to start")
+
+        cp_result = subprocess.run(
+            ["docker", "cp", f"{proxy_target}:{_CA_PATH_IN_SIDECAR}", str(dest_path)],
+            capture_output=True,
+            text=True,
+            check=False,
+        )
+        if cp_result.returncode != 0:
+            die(f"failed to extract mitmproxy CA cert from {proxy_target}: "
+                f"{cp_result.stderr.strip()}")

claude_bottle/backend/docker/prepare.py

@@ -19,6 +19,7 @@ from ...log import die
 from .. import BottleSpec
 from . import util as docker_mod
 from .bottle_plan import DockerBottlePlan
+from .mitmproxy import DockerMitmproxyProxy
 from .pipelock import DockerPipelockProxy
 
 
@@ -27,6 +28,7 @@ def resolve_plan(
     *,
     stage_dir: Path,
     proxy: DockerPipelockProxy,
+    mitm: DockerMitmproxyProxy,
 ) -> DockerBottlePlan:
     """Resolve Docker-specific names and write scratch files. Trusts
     that the agent and its skills/SSH keys are present — validation
@@ -78,6 +80,7 @@ def resolve_plan(
     prompt_file.chmod(0o600)
 
     proxy_plan = proxy.prepare(bottle, slug, stage_dir)
+    mitmproxy_plan = mitm.prepare(slug)
     resolved = resolve_env(manifest, spec.agent_name)
     # Everything that should reach the bottle by-name (so its value
     # never lands on argv or in env_file) goes into one dict. The
@@ -105,6 +108,7 @@ def resolve_plan(
         forwarded_env=forwarded_env,
         prompt_file=prompt_file,
         proxy_plan=proxy_plan,
+        mitmproxy_plan=mitmproxy_plan,
         allowlist_summary=allowlist_summary,
         use_runsc=use_runsc,
     )

claude_bottle/backend/docker/provision/ca.py

@@ -0,0 +1,55 @@
+"""Extract mitmproxy's CA cert and install it into the agent
+container's trust store.
+
+mitmproxy generates a fresh CA on first launch inside its sidecar.
+This provisioner pulls the public cert through a host stage dir,
+drops it into the agent at `/usr/local/share/ca-certificates/...`,
+runs `update-ca-certificates` to rebuild the system bundle, and
+emits a single stderr log line with the SHA-256 fingerprint."""
+
+from __future__ import annotations
+
+import hashlib
+import ssl
+import subprocess
+
+from ....log import info
+from ..bottle_plan import DockerBottlePlan
+from ..launch import AGENT_CA_PATH
+from ..mitmproxy import DockerMitmproxyProxy, mitmproxy_container_name
+
+
+def provision_ca(plan: DockerBottlePlan, target: str) -> None:
+    """Pull mitmproxy's CA cert, install in the agent, log fingerprint.
+    Called from BottleBackend.provision after the agent container is
+    up. The mitmproxy sidecar is already running (started during
+    `launch`)."""
+    sidecar = mitmproxy_container_name(plan.mitmproxy_plan.slug)
+    stage_cert = plan.stage_dir / "mitm-ca.crt"
+
+    DockerMitmproxyProxy().extract_ca_cert(sidecar, stage_cert)
+
+    container = target
+    subprocess.run(
+        ["docker", "cp", str(stage_cert), f"{container}:{AGENT_CA_PATH}"],
+        stdout=subprocess.DEVNULL,
+        check=True,
+    )
+    subprocess.run(
+        ["docker", "exec", "-u", "0", container, "chmod", "644", AGENT_CA_PATH],
+        stdout=subprocess.DEVNULL,
+        check=True,
+    )
+    subprocess.run(
+        ["docker", "exec", "-u", "0", container, "update-ca-certificates"],
+        stdout=subprocess.DEVNULL,
+        check=True,
+    )
+
+    # SHA-256 of the cert's DER bytes — the standard fingerprint
+    # form. stdlib only; never the private key (which stays in the
+    # sidecar). Logged once at launch as an audit signal.
+    pem = stage_cert.read_text()
+    der = ssl.PEM_cert_to_DER_cert(pem)
+    fingerprint = hashlib.sha256(der).hexdigest()
+    info(f"mitm ca fingerprint: sha256:{fingerprint[:32]}...")

claude_bottle/mitmproxy/__init__.py

@@ -0,0 +1,81 @@
+"""mitmproxy TLS-interception sidecar for the per-bottle egress
+topology (PRD 0005).
+
+Sits in front of pipelock on the bottle's egress path so pipelock's
+body / header / URL DLP scanners see plaintext for HTTPS targets.
+The sidecar runs in mitmproxy's `regular` mode and loads the
+vendored addon at `addon.py`; the addon forwards each decrypted
+request to pipelock as a plain HTTP forward-proxy call and gates
+the mitmproxy flow on pipelock's verdict.
+
+This module is platform-agnostic: it owns the abstract proxy
+lifecycle (prepare / start / stop / extract_ca_cert). The
+Docker-specific lifecycle lives in
+`claude_bottle/backend/docker/mitmproxy.py`.
+"""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from dataclasses import dataclass
+from pathlib import Path
+
+
+@dataclass(frozen=True)
+class MitmproxyProxyPlan:
+    """Output of MitmproxyProxy.prepare; consumed by .start when the
+    sidecar needs to be brought up.
+
+    `addon_src` is the host-side path to the vendored addon.py,
+    resolved at prepare time. `slug` is the per-agent identifier
+    used as the suffix in every per-bottle resource name. The
+    network fields default to empty and are populated by the
+    backend's launch step (via dataclasses.replace) once those
+    networks have actually been created — same pattern as
+    PipelockProxyPlan."""
+
+    addon_src: Path
+    slug: str
+    internal_network: str = ""
+    egress_network: str = ""
+
+
+class MitmproxyProxy(ABC):
+    """The mitmproxy TLS-interception sidecar. The proxy-config + addon
+    bundling are platform-agnostic; the sidecar's start/stop lifecycle
+    and the CA extraction step are backend-specific and live on
+    concrete subclasses."""
+
+    def prepare(self, slug: str) -> MitmproxyProxyPlan:
+        """Locate the vendored addon source and return the start
+        plan. The addon is checked into the project and identical
+        across bottles; per-bottle wiring (pipelock URL) is injected
+        via env vars at start time, not via a generated config."""
+        addon_src = Path(__file__).resolve().parent / "addon.py"
+        if not addon_src.is_file():
+            raise FileNotFoundError(
+                f"mitmproxy addon not found at {addon_src}; the "
+                f"package was installed incompletely"
+            )
+        return MitmproxyProxyPlan(addon_src=addon_src, slug=slug)
+
+    @abstractmethod
+    def start(self, plan: MitmproxyProxyPlan, *, pipelock_url: str) -> str:
+        """Bring up the mitmproxy sidecar according to `plan`.
+        `pipelock_url` is injected into the sidecar's env (as
+        CLAUDE_BOTTLE_PIPELOCK_URL) so the addon knows where to
+        scan. Returns the proxy_target string identifying the
+        running sidecar — the same value to pass to `.stop` and
+        `.extract_ca_cert`."""
+
+    @abstractmethod
+    def stop(self, proxy_target: str) -> None:
+        """Tear down the sidecar identified by `proxy_target`.
+        Idempotent: a missing target is success."""
+
+    @abstractmethod
+    def extract_ca_cert(self, proxy_target: str, dest_path: Path) -> None:
+        """Copy the public CA cert from the running sidecar to
+        `dest_path` on the host. Polls the sidecar for the cert
+        file to appear (mitmproxy generates the CA on first launch).
+        The private key never leaves the sidecar."""

claude_bottle/mitmproxy/addon.py

@@ -0,0 +1,169 @@
+"""mitmproxy addon: forward each decrypted request to pipelock for
+scanning, then either short-circuit with pipelock's 403 (block) or
+let mitmproxy proceed to the real upstream (allow).
+
+Loaded inside the mitmproxy sidecar container via `mitmdump -s ...`.
+Must be self-contained — the sidecar image doesn't have claude_bottle
+on its import path. Imports are limited to the Python stdlib plus
+mitmproxy itself (which is the host).
+
+Pipelock's URL is read from CLAUDE_BOTTLE_PIPELOCK_URL at startup
+(injected by DockerMitmproxyProxy.start).
+
+The verdict function `is_pipelock_block` is exported as a pure
+function so unit tests can exercise it without importing mitmproxy.
+"""
+
+from __future__ import annotations
+
+import logging
+import os
+import urllib.error
+import urllib.request
+
+
+PIPELOCK_URL_ENV = "CLAUDE_BOTTLE_PIPELOCK_URL"
+PIPELOCK_TIMEOUT_SEC = 5
+
+# Hop-by-hop headers per RFC 7230 §6.1; should not be forwarded
+# across a proxy. Lower-cased for case-insensitive comparison.
+_HOP_BY_HOP = frozenset({
+    "connection",
+    "keep-alive",
+    "proxy-authenticate",
+    "proxy-authorization",
+    "te",
+    "trailers",
+    "transfer-encoding",
+    "upgrade",
+})
+
+log = logging.getLogger("pipelock-bridge")
+
+
+def is_pipelock_block(status: int, body_bytes: bytes) -> bool:
+    """Return True iff pipelock's response indicates the proxy itself
+    blocked (DLP / allowlist), distinguishing from a relayed upstream
+    4xx that pipelock happened to forward back.
+
+    Pipelock's block bodies are plain text starting with
+    `blocked: <reason>` and the status is always 403. A relayed
+    upstream response has whatever body the upstream sent —
+    extremely unlikely to begin with `blocked: `. Pinned empirically
+    against pipelock v2.3.0 in the impl spike (DLP block:
+    "blocked: request body contains secret: GitHub Token";
+    allowlist block: "blocked: domain not in allowlist: example.com").
+
+    Long-term cleanup: file an upstream feature request for an
+    `X-Pipelock-Verdict: block` response header so we can match on a
+    structured signal instead of pattern-matching the body."""
+    return status == 403 and body_bytes.startswith(b"blocked: ")
+
+
+def _scan_via_pipelock(
+    pipelock_url: str,
+    method: str,
+    target_url: str,
+    headers: dict[str, str],
+    body: bytes,
+) -> tuple[int, bytes]:
+    """Forward the decrypted request to pipelock as a plain HTTP
+    forward-proxy call. Returns (status, body_bytes). Raises on
+    transport-level errors so the caller can fail closed.
+
+    The target URL is rewritten to http:// so pipelock receives an
+    absolute-URI forward-proxy request shape. Pipelock will scan,
+    then may attempt an upstream forward over plain HTTP — that
+    response is read back too, but the addon discards it on allow
+    (mitmproxy makes the real HTTPS request itself)."""
+    rewritten_url = target_url
+    if rewritten_url.startswith("https://"):
+        rewritten_url = "http://" + rewritten_url[len("https://"):]
+
+    forwarded_headers = {
+        k: v for k, v in headers.items()
+        if k.lower() not in _HOP_BY_HOP
+    }
+
+    proxy_handler = urllib.request.ProxyHandler({"http": pipelock_url})
+    opener = urllib.request.build_opener(proxy_handler)
+    req = urllib.request.Request(
+        url=rewritten_url,
+        data=body if body else None,
+        headers=forwarded_headers,
+        method=method,
+    )
+    try:
+        resp = opener.open(req, timeout=PIPELOCK_TIMEOUT_SEC)
+        return resp.status, resp.read()
+    except urllib.error.HTTPError as e:
+        return e.code, e.read()
+
+
+class PipelockBridge:
+    """mitmproxy addon class. mitmproxy instantiates one of these via
+    the `addons = [...]` module attribute at the bottom of this file."""
+
+    def __init__(self) -> None:
+        # Read once per sidecar lifetime. Empty string is allowed at
+        # construction (so the module can be imported in test
+        # environments) but the request handler fails closed if it's
+        # missing at request time.
+        self._pipelock_url = os.environ.get(PIPELOCK_URL_ENV, "")
+
+    def request(self, flow) -> None:
+        """mitmproxy callback. Called for each decrypted client
+        request before mitmproxy forwards to the real upstream.
+        Setting flow.response short-circuits the flow with that
+        response; leaving it None lets mitmproxy proceed."""
+        # Late import so this module can be loaded in test
+        # environments without mitmproxy installed (the verdict
+        # function is unit-testable in isolation).
+        from mitmproxy import http
+
+        if not self._pipelock_url:
+            log.error("%s is unset; failing closed", PIPELOCK_URL_ENV)
+            flow.response = http.Response.make(
+                503,
+                b"egress scanner not configured",
+                {"Content-Type": "text/plain",
+                 "X-Pipelock-Bridge": "misconfigured"},
+            )
+            return
+
+        target_url = flow.request.pretty_url
+        method = flow.request.method
+        headers = {k: v for k, v in flow.request.headers.items()}
+        body = bytes(flow.request.content or b"")
+
+        try:
+            status, response_body = _scan_via_pipelock(
+                self._pipelock_url, method, target_url, headers, body,
+            )
+        except Exception as e:
+            # Fail closed: scanner unreachable means no verdict, so
+            # refuse rather than risk leaking.
+            log.warning("pipelock unreachable; failing closed: %s", e)
+            flow.response = http.Response.make(
+                503,
+                b"egress scanner unreachable",
+                {"Content-Type": "text/plain",
+                 "X-Pipelock-Bridge": "error"},
+            )
+            return
+
+        if is_pipelock_block(status, response_body):
+            flow.response = http.Response.make(
+                status,
+                response_body,
+                {"Content-Type": "text/plain",
+                 "X-Pipelock-Bridge": "block"},
+            )
+            return
+
+        # Allow path: discard pipelock's response (it's the wasted
+        # upstream-forward attempt). Leave flow.response as None;
+        # mitmproxy proceeds to the real upstream on its own.
+
+
+addons = [PipelockBridge()]

docs/prds/0005-mitmproxy-tls-interception.md

@@ -0,0 +1,437 @@
+# PRD 0005: mitmproxy TLS interception for pipelock content scanning
+
+- **Status:** Draft (updated 2026-05-12 after open-question walkthrough)
+- **Author:** didericis
+- **Created:** 2026-05-12
+
+## Summary
+
+Add a per-bottle **mitmproxy** sidecar in front of pipelock on the
+egress path. mitmproxy bumps the agent's TLS CONNECT, decrypts the
+inner HTTP, and hands each request to a vendored Python addon. The
+addon forwards the decrypted request to pipelock as a plain HTTP
+forward-proxy call so pipelock's DLP, URL-scan, and header-scan
+layers fire on real bodies. On the verdict, the addon either
+short-circuits the flow with a 403 (block) or lets mitmproxy
+proceed to the real upstream (allow). mitmproxy itself generates
+the ephemeral per-bottle CA on startup; the public cert is copied
+into the agent's trust store and the private key dies with the
+sidecar on teardown.
+
+This is Topology A' from `docs/research/tls-mitm-for-pipelock.md` —
+a variant of the research note's Topology A after a spike showed
+mitmproxy's `upstream` mode re-wraps decrypted flows in a new
+CONNECT to the upstream proxy (which would defeat the entire
+point). The addon recovers the design by emitting plain HTTP to
+pipelock explicitly instead of relying on mitmproxy's `upstream`
+chaining.
+
+## Problem
+
+PRD 0001 wired pipelock onto every bottle's egress, but the current
+topology only sees `CONNECT` hostnames and opaque TLS bytes:
+
+```
+agent --HTTPS_PROXY--> pipelock --CONNECT host:443--> internet
+                                  \____________________________
+                                       opaque TLS bytes
+```
+
+What pipelock cannot scan in this mode is documented in
+`docs/research/tls-mitm-for-pipelock.md` §What pipelock cannot see
+today: request URLs and methods, request and response headers,
+request and response bodies, MCP JSON-RPC payloads, inner-vs-outer
+hostname (the domain-fronting check), and WebSocket frames inside a
+TLS-wrapped upgrade. The 48-pattern DLP layer this project relies on
+in PRD 0001 is therefore inert against every host in the current
+`DEFAULT_ALLOWLIST` — all of which are HTTPS-only.
+
+The integration test added in `tests/integration/test_pipelock_blocks_secret_post.py`
+demonstrates the gap concretely: pipelock's body-scan layer only
+fires when the agent is forced to send plain HTTP. Real Claude Code
+traffic to `api.anthropic.com` goes over CONNECT-tunneled TLS and
+slips past the scanner.
+
+`pipelock-assessment.md` §Scope gaps names this as a known
+limitation of the proxy-without-TLS-inspection shape. Closing it is
+the explicit motivation for `tls-mitm-for-pipelock.md`, whose
+recommendation this PRD implements (with the addon adjustment
+forced by the upstream-mode spike).
+
+## Goals / Success Criteria
+
+The feature works when all of the following are observable:
+
+- A Node request from inside a launched bottle to a CONNECT-bumped
+  HTTPS host (e.g. `https://api.anthropic.com/dlp-probe`) carrying a
+  pipelock-recognized credential pattern in the body returns 403
+  from the bottle's egress chain — not a response from the upstream.
+  The existing `test_pipelock_blocks_secret_post` test path becomes
+  the HTTPS variant of this assertion.
+- A plain HTTPS GET from inside the bottle to an allowlisted host
+  with no credential pattern (e.g. `GET https://raw.githubusercontent.com/...`)
+  returns the real upstream response — the addon doesn't break
+  clean traffic.
+- Claude Code itself reaches `api.anthropic.com` end-to-end through
+  the bottle and completes a chat round-trip. No TLS-trust errors
+  in the agent process.
+- mitmproxy's flow log and pipelock's `body_dlp` / `header_dlp` /
+  `core_dlp` event lines both appear for the same outbound request,
+  confirming the two-stage path is active.
+
+The feature is **done** when all of the following ship:
+
+- A new `MitmproxyProxy` class with the same `prepare` / `start` /
+  `stop` lifecycle shape as `PipelockProxy`, wired into the Docker
+  backend's launch step.
+- A vendored Python addon at `claude_bottle/mitmproxy/addon.py`
+  that mitmproxy loads on startup via `mitmdump -s ...`. The sidecar
+  runs in `regular` mode (default), not `upstream` mode.
+- The bottle launch step starts the mitmproxy sidecar, waits for
+  the sidecar-internal CA to be generated, copies the CA public
+  cert into the agent at `/usr/local/share/ca-certificates/claude-bottle-mitm.crt`,
+  runs `update-ca-certificates` inside the agent, and threads the
+  `NODE_EXTRA_CA_CERTS` / `SSL_CERT_FILE` / `REQUESTS_CA_BUNDLE`
+  env trio onto the agent container's runtime env.
+- The agent's `HTTPS_PROXY` / `HTTP_PROXY` point at the mitmproxy
+  sidecar (where they pointed at pipelock under PRD 0001).
+- pipelock is otherwise unchanged. It continues to load the YAML
+  PRD 0001 generates and runs its existing scanning pipeline; the
+  addon talks to it via the same forward-proxy interface today's
+  `test_pipelock_blocks_secret_post` uses.
+- On bottle teardown the mitmproxy sidecar is removed and the
+  ephemeral CA private key is gone with it.
+- An HTTPS variant of `test_pipelock_blocks_secret_post` proves
+  pipelock now blocks a credential POST over HTTPS rather than
+  plain HTTP.
+- An integration test proves a non-credential HTTPS GET through
+  the chain returns the upstream's real response.
+- The dry-run preflight (`start --dry-run`) shows the mitmproxy
+  sidecar in both text and `--format=json` output. The JSON
+  contract gains a reserved `egress.mitm: { "enabled": true, "ca_fingerprint": null }`
+  block; fingerprint is always null at dry-run because the CA
+  doesn't exist yet. Real launches emit a one-line stderr log:
+  `claude-bottle: mitm ca fingerprint: <sha256-first-16>...`.
+
+## Non-goals
+
+- **Topology C** — extending pipelock itself to terminate TLS. The
+  research note's recommended long-term shape, but substantial Go
+  work plus the Apache-2.0-vs-ELv2 question. Deferred.
+- **Topology D as canonical** — mitmproxy with a pipelock `/scan`
+  HTTP endpoint. The addon in this PRD talks to pipelock via its
+  existing forward-proxy interface; no upstream pipelock change
+  needed.
+- **Persistent or shared CA across bottles.** Each bottle gets a
+  fresh CA generated by its own mitmproxy at startup.
+- **Selective bumping ("ignore_hosts") as a v1 manifest field.**
+  v1 bumps every CONNECT. If a future allowlisted host turns out
+  to pin (Mobile / Chromium-style cert pinning), a follow-up PRD
+  adds the per-host opt-out via `bottle.egress.tls_bump_ignore`.
+  Strictly additive.
+- **HTTP/3 / QUIC.** mitmproxy's HTTP/3 support is experimental.
+  v1 relies on the v1-egress iptables layer blocking UDP/443 to
+  force clients onto HTTP/2 over TCP, which mitmproxy 12 inspects
+  natively (verified by spike).
+- **Raw TCP / non-HTTP TLS interception.** mitmproxy supports it
+  via `--mode reverse:`, not in CONNECT-bump mode. SSH and any
+  future raw-TCP egress route around mitmproxy entirely.
+- **Trust-store rewiring for non-Debian agent images.** The
+  current `Dockerfile` is `node:22-slim` (Debian). If a future base
+  switches to Red-Hat-family, the `update-ca-certificates` step
+  becomes `update-ca-trust`. Out of scope until the base changes.
+- **Response-body scanning.** Pipelock supports it; we don't wire
+  it in v1 because the addon would need to ferry the upstream
+  response back through pipelock's scanner, which the forward-
+  proxy interface doesn't support cleanly. v2 candidate.
+- **MCP scanning on the bumped path.** Only fires on MCP-formatted
+  JSON-RPC payloads inside tool calls. Not relevant to plain HTTPS
+  agent traffic and out of v1 scope.
+- **Domain-fronting verification.** Once the addon sees the inner
+  `Host` / `:authority`, comparing it to the outer CONNECT target
+  catches domain fronting. Worth ~10 lines in the addon, but
+  defer until the rest of v1 is settled.
+- **Host-side openssl / `cryptography` for CA generation.** The
+  research note's open question on this is resolved by letting
+  mitmproxy itself generate the CA (it does so on first launch).
+  No new host-side crypto.
+
+## Scope
+
+### In scope
+
+- New `claude_bottle/mitmproxy/` package:
+  - `__init__.py` — backend-agnostic. Constants (sidecar port,
+    image-pin digest, the in-container addon path), the abstract
+    `MitmproxyProxy` class with `prepare` / `start` / `stop` shape
+    mirroring `PipelockProxy`, and the small helper that reads the
+    CA fingerprint from a PEM file via `openssl x509 -fingerprint`
+    shelled out.
+  - `addon.py` — the Python addon mitmproxy loads. ~80–150 lines.
+    For each `request` event: forward the decrypted request to
+    pipelock at `http://claude-bottle-pipelock-<slug>:8888` as a
+    plain HTTP forward-proxy call (absolute-URI form). Inspect
+    pipelock's response. If status is 403 *and* the body matches
+    pipelock's known block-event shape, set the flow's response to
+    a 403 with pipelock's body and short-circuit. Otherwise,
+    discard pipelock's response (and any wasted upstream-leg
+    response from pipelock's forwarder) and let mitmproxy proceed
+    to the real upstream.
+- New `claude_bottle/backend/docker/mitmproxy.py` —
+  `DockerMitmproxyProxy(MitmproxyProxy)` with the Docker-specific
+  start/stop lifecycle. `start(plan)` does `docker create` /
+  `docker cp addon.py …` / `docker network connect` / `docker start`,
+  analogous to the existing `DockerPipelockProxy.start`. Injects
+  `CLAUDE_BOTTLE_PIPELOCK_URL` into the sidecar env so the addon
+  knows where pipelock lives.
+- New provisioner `claude_bottle/backend/docker/provision/ca.py`.
+  Polls mitmproxy for the cert file, copies it through a host
+  stage dir into the agent, runs `update-ca-certificates` inside
+  the agent, computes the SHA-256 fingerprint, and prints the
+  one-line stderr log.
+- `BottleBackend.provision_ca(plan, target)` joins the four
+  existing provisioner methods on the abstract base. Default impl
+  is no-op so other backends don't break when they don't yet
+  implement TLS interception.
+- `DockerBottlePlan` grows a `mitmproxy_plan` field mirroring the
+  existing `proxy_plan`.
+- Agent container `docker run` invocation:
+  - `HTTPS_PROXY` / `HTTP_PROXY` change from the pipelock service
+    name to the mitmproxy service name.
+  - Three `-e` flags set the CA env trio so they're inherited by
+    the eventual `docker exec claude` (Docker propagates run-time
+    env into exec by default; fallback in Q1 below).
+- Dry-run preflight rendering of the mitmproxy entry (text + JSON).
+  JSON gains `egress.mitm: { "enabled": true, "ca_fingerprint": null }`.
+- One stderr log line at launch with the CA fingerprint.
+- Two new integration tests under `tests/integration/`:
+  - `test_mitmproxy_blocks_secret_https_post.py` — HTTPS variant
+    of the existing block-secret test. Asserts pipelock's body
+    DLP fires on a credential POST tunneled through CONNECT.
+  - `test_mitmproxy_allows_normal_https.py` — confirms a plain
+    HTTPS GET on an allowlisted host returns the upstream response,
+    isolating the addon's pass-through path from the block path.
+- Unit tests for the addon's verdict logic (block vs allow on
+  status + body shape, edge cases) using mitmproxy's `mitmproxy.test`
+  flow fixtures. Unit tests for the proxy config builder
+  (mirroring `tests/unit/test_pipelock_yaml.py`).
+
+### Out of scope
+
+- The v1 iptables + dnsmasq layer (separate PRD; see
+  `network-egress-guard.md`). mitmproxy covers HTTP/HTTPS only;
+  raw TCP, UDP, ICMP, and direct DNS still need the IP-level layer.
+- Pipelock config changes. Pipelock continues to load the YAML
+  PRD 0001 generates; the addon talks to it via the existing
+  forward-proxy interface.
+- A bottle-level toggle to skip mitmproxy entirely. v1 always
+  wires it in.
+- Pinning-host detection automation. The cost of finding out (per
+  research) is a single 5-minute test before adding a host; it
+  stays a manual step.
+- Pipelock upstream contributions for an `X-Pipelock-Verdict` header.
+  Possible follow-up. Until then the addon distinguishes blocks
+  from passes via status + body fingerprint.
+
+## Proposed Design
+
+### Topology
+
+```
+agent --HTTPS_PROXY--> mitmproxy --addon--> pipelock     (scan)
+                       (bump TLS)              |
+                          ^                    | (verdict via status code)
+                          |                    v
+                          +-- on allow ----- real upstream
+                                              (mitmproxy as client)
+```
+
+All three containers live on the same per-bottle internal Docker
+network. mitmproxy and pipelock are both attached to the per-bottle
+egress bridge for real-internet reach; the agent has no default
+route.
+
+Concretely:
+
+- Agent sets `HTTPS_PROXY=http://claude-bottle-mitm-<slug>:<port>`.
+  PRD 0001 had this pointing at pipelock; the hostname swap is the
+  only agent-side env change.
+- mitmproxy runs in **`regular`** mode (default; no `--mode` flag).
+  It bumps every CONNECT, generates fake leaf certs signed by its
+  own CA, and presents them to the agent.
+- The addon, loaded via `mitmdump -s /addon/addon.py`, intercepts
+  each decrypted `request` event. It forwards the request to
+  pipelock at `http://claude-bottle-pipelock-<slug>:8888` as a
+  plain HTTP forward-proxy call (absolute-URI form), so pipelock
+  sees the full URL, headers, and body.
+- The addon inspects pipelock's response. If status is 403 *and*
+  the response body matches pipelock's known block-event shape,
+  the addon sets the mitmproxy flow's response to a 403 with
+  pipelock's body and short-circuits. Otherwise — including the
+  case where pipelock's forwarder attempted the upstream and got
+  a 4xx — the addon discards pipelock's response and lets
+  mitmproxy proceed to the real upstream.
+- mitmproxy completes the outbound TLS to the real destination
+  using its built-in trust store, just like any other forward
+  proxy. Pipelock is only involved as a scanner.
+
+The trade-off: pipelock makes a wasted upstream forward attempt
+for every allowed request (it tries to forward over plain HTTP to
+a real HTTPS-only host, which fails with the upstream's 4xx). This
+is benign — the scan completes before forwarding, the verdict
+reaches the addon, the upstream-side request happens to die in
+pipelock's forwarder rather than reach the agent. Acceptable cost
+for the visibility win. A pipelock-side improvement (skip the
+forward when the addon only needs the scan verdict) is a future
+optimization.
+
+### New components
+
+- `claude_bottle/mitmproxy/__init__.py` — backend-agnostic
+  abstract base, constants, the `openssl x509 -fingerprint` helper.
+- `claude_bottle/mitmproxy/addon.py` — the scanning addon.
+  Reads pipelock's URL from `CLAUDE_BOTTLE_PIPELOCK_URL` (injected
+  into the sidecar env by the proxy's `start`). For each
+  `request` flow: synchronously POST to pipelock; inspect status
+  + body; either short-circuit with 403 or fall through.
+- `claude_bottle/backend/docker/mitmproxy.py` —
+  `DockerMitmproxyProxy(MitmproxyProxy)` with start/stop, the
+  `docker cp` of the addon into the sidecar before `docker start`,
+  and the `CLAUDE_BOTTLE_PIPELOCK_URL` wiring.
+
+### CA lifecycle
+
+Simplified by letting mitmproxy own the generation:
+
+- **Generation.** mitmproxy generates a fresh CA on startup
+  inside its container at `/home/mitmproxy/.mitmproxy/mitmproxy-ca-cert.pem`
+  (public) + `mitmproxy-ca.pem` (private). No host-side openssl
+  for *generation*; no host-side Python `cryptography` dep.
+- **Volume strategy.** Container-internal only. No host bind
+  mount means the CA dies with the container.
+- **Extraction.** `provision_ca` polls (~1s) for the cert file
+  via `docker exec`, then `docker cp` to host stage dir, then
+  `docker cp` into the agent. Host stage dir gets cleaned up by
+  the existing `start.py` `finally` block.
+- **Bottle install.**
+  1. `docker cp <host stage>/mitm-ca.crt agent-<slug>:/usr/local/share/ca-certificates/claude-bottle-mitm.crt`
+  2. `docker exec -u 0 agent-<slug> chmod 644 …`
+  3. `docker exec -u 0 agent-<slug> update-ca-certificates`
+  4. Three `-e` flags on `docker run` set the env trio
+     (`NODE_EXTRA_CA_CERTS=…/claude-bottle-mitm.crt`,
+     `SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt`,
+     `REQUESTS_CA_BUNDLE=/etc/ssl/certs/ca-certificates.crt`) so
+     `docker exec claude` inherits them.
+- **Teardown.** Sidecar container removed; CA private key gone.
+- **Fingerprint.** Computed post-extraction via shelled-out
+  `openssl x509 -fingerprint -sha256 -noout`. Logged once to
+  stderr at launch; never the private key.
+
+### Data model changes
+
+None to the manifest schema. The dry-run JSON contract gains a
+reserved `egress.mitm: { "enabled": true, "ca_fingerprint": null }`
+block. Fingerprint is always null at dry-run (CA doesn't exist
+yet) but the field is reserved so future schema additions stay
+non-breaking.
+
+A future selective-bump knob would add
+`bottle.egress.tls_bump_ignore: [host, ...]` per the research
+note. Strictly additive when it lands.
+
+### Existing code touched
+
+- **`claude_bottle/backend/docker/launch.py`** — bring up the
+  mitmproxy sidecar between pipelock and the agent. Repoint the
+  agent's `HTTPS_PROXY` / `HTTP_PROXY` env flags to mitmproxy.
+  Register an `ExitStack` callback for mitmproxy teardown. Print
+  the CA fingerprint once the sidecar reports ready.
+- **`claude_bottle/backend/docker/prepare.py`** — call into
+  `MitmproxyProxy.prepare(...)` alongside `PipelockProxy.prepare(...)`,
+  populate `DockerBottlePlan.mitmproxy_plan`.
+- **`claude_bottle/backend/docker/backend.py`** — add the
+  `DockerMitmproxyProxy` instance attribute (`self._mitm`) and
+  thread it through `launch` + cleanup, mirroring `self._proxy`.
+- **`claude_bottle/backend/docker/bottle_plan.py`** — new
+  `mitmproxy_plan` field. `print()` and `to_dict()` learn to
+  render the mitmproxy entry and the `egress.mitm` JSON block.
+- **`claude_bottle/backend/__init__.py`** — abstract
+  `BottleBackend.provision_ca` joins the four existing
+  provisioners; default no-op.
+- **`tests/integration/`** — two new tests as described above.
+- **`tests/unit/`** — addon-verdict tests, mitmproxy-config
+  builder tests, dry-run-plan test updated for the new
+  `egress.mitm` block.
+
+### External dependencies
+
+- **mitmproxy Docker image** pinned by digest on the `12.x` line.
+  Bumped deliberately, mirroring the pipelock pin. Verified by
+  spike to speak h2 on both halves.
+- No new host-side runtimes. mitmproxy generates the CA;
+  fingerprint via the `openssl` already present on Debian / macOS
+  / ubuntu-latest runners.
+
+## Open questions
+
+(rewritten — most of the original v1 questions are now closed by
+the walkthrough spikes; what remains is addon-implementation
+specifics worth pinning during the first impl turn.)
+
+- **Pipelock's 403-body fingerprint.** The addon needs to
+  distinguish a pipelock block (DLP / host) from a real-upstream
+  4xx that pipelock's forwarder relayed back. Most likely shape:
+  pipelock's 403 response carries a JSON body with `event` /
+  `scanner` fields, whereas a real-upstream 4xx carries whatever
+  the upstream sent. Pin the exact fingerprint by inspecting
+  pipelock's actual 403 body bytes at impl time. Long-term
+  cleanup: file an upstream feature request for an
+  `X-Pipelock-Verdict: block` response header so the addon can
+  read a structured signal instead of pattern-matching the body.
+- **Docker run env-var inheritance through docker exec.** Plan
+  assumes `docker run -e VAR=value` propagates to subsequent
+  `docker exec` invocations. The Docker docs say so; not yet
+  empirically pinned on this project's runner setup. Verify in
+  the first impl turn. Trivial fallback: thread the three `-e`
+  flags onto every `DockerBottle.exec*` call.
+- **Addon synchronous-call latency.** The addon makes a sync HTTP
+  call to pipelock per outbound flow. Pipelock is on the same
+  internal Docker network; expected per-call latency is well
+  under 10ms. Confirm under the parallel-request load Claude Code
+  generates (most likely a non-issue — Claude is single-stream
+  request-wise).
+- **Addon test fixtures.** mitmproxy ships `mitmproxy.test` with
+  flow fixtures; addons can be unit-tested without a running
+  proxy. Confirm the import path and recommended fixture shape at
+  impl time; structure the addon so the verdict-decision is a
+  pure function that's trivially testable in isolation from any
+  HTTP I/O.
+- **Pipelock allowing the addon's forwarded request through.**
+  pipelock will see the addon's request as coming from the
+  mitmproxy sidecar's IP on the internal network. Confirm
+  pipelock has no client-IP allowlist that would reject these.
+  Likely fine — pipelock's `client_ip` is informational in the
+  scan event, not a gate.
+
+## References
+
+- `docs/research/tls-mitm-for-pipelock.md` — primary source. This
+  PRD implements a variant of §Recommendation (Topology A) after
+  the spike documented under "Open questions" §1 falsified the
+  `upstream` mode assumption.
+- `docs/research/pipelock-assessment.md` §Scope gaps — names the
+  TLS-inspection gap closed here.
+- `docs/prds/0001-per-agent-egress-proxy-via-pipelock.md` —
+  egress-proxy baseline this PRD extends.
+- `docs/prds/0003-bottle-backend-abstraction.md` — backend ABC
+  contract this PRD adds a `provision_ca` method to.
+- `docs/prds/0004-split-out-provisioners.md` — per-provisioner
+  module pattern reused for the new CA provisioner.
+- mitmproxy: <https://mitmproxy.org>,
+  <https://github.com/mitmproxy/mitmproxy>
+- mitmproxy modes: <https://docs.mitmproxy.org/stable/concepts/modes/>
+- mitmproxy CA cert installation:
+  <https://docs.mitmproxy.org/stable/concepts/certificates/>
+- mitmproxy addon API: <https://docs.mitmproxy.org/stable/addons-overview/>
+- Node `NODE_EXTRA_CA_CERTS`:
+  <https://nodejs.org/api/cli.html#node_extra_ca_certsfile>

tests/integration/test_dry_run_plan.py

@@ -92,6 +92,12 @@ class TestDryRunPlan(unittest.TestCase):
             self.assertEqual(sorted(set(hosts)), hosts,
                              "hosts must be sorted and deduplicated")
 
+            # PRD 0005: TLS interception block is part of the JSON
+            # contract. Fingerprint is null at dry-run (CA doesn't
+            # exist yet); real launches print it to stderr.
+            self.assertEqual({"enabled": True, "ca_fingerprint": None},
+                             plan["egress"]["mitm"])
+
             # No Docker side effects (see the GITEA_ACTIONS skip note
             # above — this guard runs locally only).
             if check_side_effects:

tests/integration/test_mitmproxy_allows_normal_https.py

@@ -0,0 +1,167 @@
+"""Integration: with mitmproxy in front of pipelock, a plain HTTPS
+GET to an allowlisted host with no credential pattern still gets
+through end-to-end.
+
+The complement to test_mitmproxy_blocks_secret_https_post — together
+they isolate the addon's two paths (block vs. allow). This test
+also functions as the end-to-end TLS-trust check: if the agent's
+trust store didn't have mitmproxy's CA installed, the TLS handshake
+between the agent and mitmproxy's bumped cert would fail and the
+fetch would throw before we ever saw a response.
+"""
+
+from __future__ import annotations
+
+import os
+import shutil
+import tempfile
+import unittest
+from pathlib import Path
+
+from claude_bottle.backend import BottleSpec, get_bottle_backend
+from tests._docker import skip_unless_docker
+from tests.fixtures import fixture_minimal
+
+
+# raw.githubusercontent.com is in the baked-in DEFAULT_ALLOWLIST.
+# Pick a file path that's stable enough across runs — `git`'s own
+# README.md on the master branch is a long-lived artifact and one
+# of github's most-trafficked raw files.
+_TARGET_URL = "https://raw.githubusercontent.com/git/git/master/README.md"
+
+# stdlib http (for CONNECT) + tls (for the bumped tunnel); see the
+# block test for the rationale on not pulling undici in as a dep.
+#
+# Output contract:
+#   - "status=<code>"   HTTP status from upstream (or addon, if
+#                       blocked)
+#   - "bridge=<value>"  X-Pipelock-Bridge header; empty on allow
+#   - "len=<N>"         response body length, sanity-check it's a
+#                       real response and not an empty proxy stub
+#   - "error=<...>"     thrown error
+_PROBE_JS = r"""
+const http = require('http');
+const tls = require('tls');
+
+const proxy = new URL(process.env.HTTPS_PROXY);
+
+const connectReq = http.request({
+  host: proxy.hostname,
+  port: proxy.port,
+  method: 'CONNECT',
+  path: 'raw.githubusercontent.com:443',
+});
+connectReq.setTimeout(10000, () => {
+  console.log('timeout=connect');
+  connectReq.destroy();
+});
+connectReq.on('error', (e) => {
+  console.log('error=' + (e.code || '') + ' ' + e.message);
+});
+connectReq.on('connect', (res, socket) => {
+  if (res.statusCode !== 200) {
+    console.log('status=' + res.statusCode);
+    console.log('bridge=' + (res.headers['x-pipelock-bridge'] || ''));
+    return;
+  }
+  const tlsSocket = tls.connect({
+    socket: socket,
+    servername: 'raw.githubusercontent.com',
+  });
+  tlsSocket.on('secureConnect', () => {
+    tlsSocket.write(
+      'GET /git/git/master/README.md HTTP/1.1\r\n' +
+      'Host: raw.githubusercontent.com\r\n' +
+      'User-Agent: claude-bottle-mitm-test\r\n' +
+      'Accept: */*\r\n' +
+      'Connection: close\r\n' +
+      '\r\n'
+    );
+  });
+  let buf = Buffer.alloc(0);
+  tlsSocket.on('data', (c) => { buf = Buffer.concat([buf, c]); });
+  tlsSocket.on('end', () => {
+    const text = buf.toString('utf8');
+    const headersEnd = text.indexOf('\r\n\r\n');
+    const head = headersEnd >= 0 ? text.slice(0, headersEnd) : text;
+    const body = headersEnd >= 0 ? text.slice(headersEnd + 4) : '';
+    const lines = head.split('\r\n');
+    const m = lines[0].match(/HTTP\/[\d.]+ (\d+)/);
+    let bridge = '';
+    for (let i = 1; i < lines.length; i++) {
+      const ix = lines[i].indexOf(': ');
+      if (ix < 0) continue;
+      if (lines[i].slice(0, ix).toLowerCase() === 'x-pipelock-bridge') {
+        bridge = lines[i].slice(ix + 2);
+      }
+    }
+    console.log('status=' + (m ? m[1] : '?'));
+    console.log('bridge=' + bridge);
+    console.log('len=' + body.length);
+  });
+  tlsSocket.on('error', (e) => {
+    console.log('tls_error=' + (e.code || '') + ' ' + e.message);
+  });
+});
+connectReq.end();
+"""
+
+
+@skip_unless_docker()
+class TestMitmproxyAllowsNormalHttps(unittest.TestCase):
+    @unittest.skipIf(
+        os.environ.get("GITEA_ACTIONS") == "true",
+        "skipped under act_runner: docker socket mount topology breaks "
+        "in-process visibility of networks created on the host daemon",
+    )
+    def test_https_get_to_allowed_host_succeeds(self):
+        backend = get_bottle_backend()
+        stage_dir = Path(tempfile.mkdtemp(prefix="cb-test-stage."))
+        try:
+            spec = BottleSpec(
+                manifest=fixture_minimal(),
+                agent_name="demo",
+                copy_cwd=False,
+                user_cwd=str(stage_dir),
+                forward_oauth_token=False,
+            )
+            plan = backend.prepare(spec, stage_dir=stage_dir)
+            with backend.launch(plan) as bottle:
+                script = (
+                    "set -e\n"
+                    "cat > /tmp/probe.js <<'PROBE_EOF'\n"
+                    f"{_PROBE_JS}\n"
+                    "PROBE_EOF\n"
+                    "node /tmp/probe.js\n"
+                )
+                result = bottle.exec(script)
+        finally:
+            shutil.rmtree(stage_dir, ignore_errors=True)
+
+        self.assertEqual(
+            0, result.returncode,
+            f"exec wrapper failed: stdout={result.stdout!r} stderr={result.stderr!r}",
+        )
+        # The TLS-trust setup is implicit here — if it had failed,
+        # fetch would have thrown rather than returned a status.
+        self.assertIn(
+            "status=200", result.stdout,
+            f"expected 200 from raw.githubusercontent.com; got: {result.stdout!r}",
+        )
+        # X-Pipelock-Bridge is set only on the addon's short-circuit
+        # paths (block / misconfigured / scanner-unreachable). An
+        # allow flow goes straight through mitmproxy to upstream and
+        # the header should be absent.
+        self.assertIn(
+            "bridge=\n", result.stdout,
+            f"X-Pipelock-Bridge unexpectedly present on the allow "
+            f"path: {result.stdout!r}",
+        )
+        # Sanity: the README is many KB. An empty body would suggest
+        # the response was synthesized by something in the chain
+        # rather than fetched from github.
+        self.assertNotIn("len=0\n", result.stdout)
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/integration/test_mitmproxy_blocks_secret_https_post.py

@@ -0,0 +1,172 @@
+"""Integration: with mitmproxy in front of pipelock, a credential
+POST sent over HTTPS is now blocked by pipelock's body-scan layer.
+
+This is the HTTPS variant of test_pipelock_blocks_secret_post — the
+two together prove the TLS-interception layer is doing the work the
+PRD targets. The earlier plain-HTTP test only fired because the agent
+was forced to bypass TLS; real Claude Code traffic to api.anthropic.com
+goes over CONNECT-tunneled HTTPS and would have slipped past pipelock
+prior to this PRD.
+
+End-to-end: drives `BottleBackend.prepare → launch` so the real
+image build, network plumbing, pipelock sidecar, mitmproxy sidecar,
+ephemeral CA generation, and trust-store install are all in the
+loop.
+"""
+
+from __future__ import annotations
+
+import os
+import shutil
+import tempfile
+import unittest
+from pathlib import Path
+
+from claude_bottle.backend import BottleSpec, get_bottle_backend
+from claude_bottle.manifest import Manifest
+from tests._docker import skip_unless_docker
+
+
+# Synthetic value shaped like a GitHub Personal Access Token; not a
+# real credential. Pipelock's default DLP rules pattern-match this
+# format and mitmproxy's addon short-circuits with the 403 it
+# receives back.
+_FAKE_TOKEN = "ghp_aB3cD4eF5gH6iJ7kL8mN9oP0qR1sT2uV3wX4yZ"
+
+
+# Build the request by hand using stdlib `http` (for CONNECT) and
+# `tls` (for the bumped tunnel). Node 22's `fetch` doesn't expose
+# proxy configuration without undici as an installable dep, and
+# this project keeps the bottle image dep-light. NODE_EXTRA_CA_CERTS
+# is wired by launch.py so the agent trusts mitmproxy's bumped cert.
+#
+# Output contract (parsed by the test):
+#   - "status=<code>"   HTTP status of the decrypted response
+#   - "bridge=<value>"  X-Pipelock-Bridge header from the addon's
+#                       short-circuit, empty on the allow path
+#   - "error=<...>"     thrown error
+_PROBE_JS = r"""
+const http = require('http');
+const tls = require('tls');
+
+const proxy = new URL(process.env.HTTPS_PROXY);
+const body = 'token=' + process.env.FAKE_TOKEN;
+
+const connectReq = http.request({
+  host: proxy.hostname,
+  port: proxy.port,
+  method: 'CONNECT',
+  path: 'api.anthropic.com:443',
+});
+connectReq.setTimeout(8000, () => {
+  console.log('timeout=connect');
+  connectReq.destroy();
+});
+connectReq.on('error', (e) => {
+  console.log('error=' + (e.code || '') + ' ' + e.message);
+});
+connectReq.on('connect', (res, socket) => {
+  if (res.statusCode !== 200) {
+    console.log('status=' + res.statusCode);
+    console.log('bridge=' + (res.headers['x-pipelock-bridge'] || ''));
+    return;
+  }
+  const tlsSocket = tls.connect({
+    socket: socket,
+    servername: 'api.anthropic.com',
+  });
+  tlsSocket.on('secureConnect', () => {
+    tlsSocket.write(
+      'POST /dlp-probe HTTP/1.1\r\n' +
+      'Host: api.anthropic.com\r\n' +
+      'Content-Type: application/x-www-form-urlencoded\r\n' +
+      'Content-Length: ' + Buffer.byteLength(body) + '\r\n' +
+      'Connection: close\r\n' +
+      '\r\n' + body
+    );
+  });
+  let buf = '';
+  tlsSocket.on('data', (c) => { buf += c.toString('utf8'); });
+  tlsSocket.on('end', () => {
+    const lines = buf.split('\r\n');
+    const m = lines[0].match(/HTTP\/[\d.]+ (\d+)/);
+    let bridge = '';
+    for (let i = 1; i < lines.length; i++) {
+      if (lines[i] === '') break;
+      const ix = lines[i].indexOf(': ');
+      if (ix < 0) continue;
+      if (lines[i].slice(0, ix).toLowerCase() === 'x-pipelock-bridge') {
+        bridge = lines[i].slice(ix + 2);
+      }
+    }
+    console.log('status=' + (m ? m[1] : '?'));
+    console.log('bridge=' + bridge);
+  });
+  tlsSocket.on('error', (e) => {
+    console.log('tls_error=' + (e.code || '') + ' ' + e.message);
+  });
+});
+connectReq.end();
+"""
+
+
+@skip_unless_docker()
+class TestMitmproxyBlocksSecretHttpsPost(unittest.TestCase):
+    @unittest.skipIf(
+        os.environ.get("GITEA_ACTIONS") == "true",
+        "skipped under act_runner: docker socket mount topology breaks "
+        "in-process visibility of networks created on the host daemon",
+    )
+    def test_https_post_with_credential_body_is_blocked(self):
+        manifest = Manifest.from_json_obj({
+            "bottles": {
+                "dev": {"env": {"FAKE_TOKEN": _FAKE_TOKEN}},
+            },
+            "agents": {
+                "demo": {"skills": [], "prompt": "", "bottle": "dev"},
+            },
+        })
+        backend = get_bottle_backend()
+        stage_dir = Path(tempfile.mkdtemp(prefix="cb-test-stage."))
+        try:
+            spec = BottleSpec(
+                manifest=manifest,
+                agent_name="demo",
+                copy_cwd=False,
+                user_cwd=str(stage_dir),
+                forward_oauth_token=False,
+            )
+            plan = backend.prepare(spec, stage_dir=stage_dir)
+            with backend.launch(plan) as bottle:
+                script = (
+                    "set -e\n"
+                    "cat > /tmp/probe.js <<'PROBE_EOF'\n"
+                    f"{_PROBE_JS}\n"
+                    "PROBE_EOF\n"
+                    "node /tmp/probe.js\n"
+                )
+                result = bottle.exec(script)
+        finally:
+            shutil.rmtree(stage_dir, ignore_errors=True)
+
+        self.assertEqual(
+            0, result.returncode,
+            f"exec wrapper failed: stdout={result.stdout!r} stderr={result.stderr!r}",
+        )
+        # The addon short-circuits the flow with X-Pipelock-Bridge: block
+        # on a pipelock block — the cleanest signal that the chain
+        # mitmproxy(bump) -> addon(forward) -> pipelock(scan) -> block
+        # all happened, end to end.
+        self.assertIn(
+            "status=403", result.stdout,
+            f"expected 403 from pipelock block; got: {result.stdout!r}",
+        )
+        self.assertIn(
+            "bridge=block", result.stdout,
+            f"X-Pipelock-Bridge header missing; the addon may not be "
+            f"in path: {result.stdout!r}",
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/unit/test_mitmproxy_verdict.py

@@ -0,0 +1,62 @@
+"""Unit: the addon's verdict function pinning pipelock-block vs.
+relayed-upstream 4xx.
+
+The fingerprint shape is the contract the addon depends on; this
+test should break loudly if pipelock changes its 403-body prefix
+under a version bump."""
+
+from __future__ import annotations
+
+import unittest
+
+from claude_bottle.mitmproxy.addon import is_pipelock_block
+
+
+class TestIsPipelockBlock(unittest.TestCase):
+    def test_block_dlp_body(self):
+        # Pipelock v2.3.0 DLP block, captured in the impl spike.
+        self.assertTrue(is_pipelock_block(
+            403,
+            b"blocked: request body contains secret: GitHub Token",
+        ))
+
+    def test_block_allowlist_body(self):
+        # Pipelock v2.3.0 allowlist block, captured in the impl spike.
+        self.assertTrue(is_pipelock_block(
+            403,
+            b"blocked: domain not in allowlist: example.com",
+        ))
+
+    def test_block_header_dlp_body(self):
+        # Header DLP path; same body prefix per the spike.
+        self.assertTrue(is_pipelock_block(
+            403,
+            b"blocked: request header Authorization contains secret",
+        ))
+
+    def test_403_without_blocked_prefix_is_not_a_block(self):
+        # A real-upstream 403 relayed by pipelock — body is whatever
+        # the upstream sent, almost certainly not starting with
+        # `blocked: `. Must be treated as allow so the addon hands
+        # the flow back to mitmproxy.
+        self.assertFalse(is_pipelock_block(
+            403,
+            b'{"error":"forbidden","detail":"insufficient permissions"}',
+        ))
+
+    def test_non_403_with_blocked_prefix_is_not_a_block(self):
+        # Defensive: if some intermediate ever returns 502/504 with
+        # a body that happens to begin `blocked: `, we should still
+        # not short-circuit. Block status is always 403 by contract.
+        self.assertFalse(is_pipelock_block(502, b"blocked: ..."))
+
+    def test_200_is_not_a_block(self):
+        # Allow path, normal forwarded response.
+        self.assertFalse(is_pipelock_block(200, b'{"ok":true}'))
+
+    def test_empty_body_is_not_a_block(self):
+        self.assertFalse(is_pipelock_block(403, b""))
+
+
+if __name__ == "__main__":
+    unittest.main()