feat(emailgen): Ollama-driven fake email worker for IMAP/POP3 deckies

Second orchestrator worker (decnet emailgen) that drips persona-driven,
threaded, multi-language fake emails into running mail deckies.  Personas
live on Topology.email_personas; topology-wide language_default falls
through to any persona that doesn't pin its own.  Em-dashes are
suppressed at the prompt layer by default and only lifted for personas
explicitly marked uses_llms_heavily — em-dashes are an LLM tell and a
flat corpus of em-dashed mail is a giveaway.

EML delivery writes into /var/spool/decnet-emails/<thread>/<msg>.eml on
the mail decky via docker exec; wiring the IMAP/POP3 templates to read
from that spool (replacing the hardcoded _BAIT_EMAILS) is the next step.

decnet/bus/topics.py

@@ -12,6 +12,7 @@ Token structure (NATS-style, dot-separated):
     decky.{decky_id}.traffic
     orchestrator.traffic.{decky_id}
     orchestrator.file.{decky_id}
+    orchestrator.email.{decky_id}
     attacker.observed
     attacker.scored
     attacker.session.started
@@ -172,6 +173,11 @@ CREDENTIAL_REUSE_DETECTED = "reuse.detected"
 # stream via ``orchestrator.*.<decky_uuid>``.
 ORCHESTRATOR_TRAFFIC = "traffic"
 ORCHESTRATOR_FILE = "file"
+# Emailgen — published by the ``decnet emailgen`` worker once per generated
+# fake email delivered into a mail decky's maildir.  Third token is the
+# destination mail-decky uuid (the IMAP/POP3 host serving the mailbox),
+# matching the ``orchestrator.*.<decky_uuid>`` subscription pattern.
+ORCHESTRATOR_EMAIL = "email"
 
 # System event types.
 SYSTEM_LOG = "log"

decnet/cli/__init__.py

@@ -24,6 +24,7 @@ from . import (
     bus,
     db,
     deploy,
+    emailgen,
     forwarder,
     geoip,
     init,
@@ -56,7 +57,7 @@ for _mod in (
     api, swarmctl, agent, updater, listener, forwarder,
     swarm,
     deploy, lifecycle, workers, inventory,
-    web, profiler, orchestrator, reconciler, sniffer, db,
+    web, profiler, orchestrator, emailgen, reconciler, sniffer, db,
     topology, bus, geoip, init, webhook,
 ):
     _mod.register(app)

decnet/cli/emailgen.py

@@ -0,0 +1,66 @@
+"""``decnet emailgen`` — second orchestrator worker.
+
+Sibling of :mod:`decnet.cli.orchestrator`.  Two distinct CLI entrypoints
+match the "workers are independent, never coupled" principle: a wedged
+ollama call in emailgen does not stall the SSH-flavoured orchestrator,
+and systemd supervises each loop separately.
+"""
+from __future__ import annotations
+
+import os
+
+import typer
+
+from . import utils as _utils
+from .utils import console, log
+
+
+def register(app: typer.Typer) -> None:
+    @app.command(name="emailgen")
+    def emailgen_cmd(
+        interval: int = typer.Option(
+            300, "--interval", "-i",
+            help="Seconds between fake-email generation ticks (default 5m)",
+        ),
+        daemon: bool = typer.Option(
+            False, "--daemon", "-d",
+            help="Detach to background as a daemon process",
+        ),
+        model: str = typer.Option(
+            "", "--model", "-m",
+            help="Ollama model override (defaults to $DECNET_EMAILGEN_MODEL "
+                 "or 'llama3.1')",
+        ),
+    ) -> None:
+        """Drip fake corporate emails into running IMAP/POP3 mail deckies."""
+        import asyncio
+        from decnet.orchestrator.emailgen import emailgen_worker
+        from decnet.web.dependencies import repo
+
+        if daemon:
+            log.info("emailgen daemonizing interval=%d", interval)
+            _utils._daemonize()
+
+        # Honour the env var when the flag was left empty so systemd unit
+        # files can configure the model centrally without per-host CLI
+        # tweaks.  Empty -> let the worker apply its own default.
+        resolved_model = model or os.environ.get("DECNET_EMAILGEN_MODEL", "")
+        log.info(
+            "emailgen starting interval=%d model=%s",
+            interval, resolved_model or "default",
+        )
+        console.print(
+            f"[bold cyan]Emailgen starting[/] (interval: {interval}s"
+            f"{', model: ' + resolved_model if resolved_model else ''})"
+        )
+
+        async def _run() -> None:
+            await repo.initialize()
+            await emailgen_worker(
+                repo, interval=interval, model=resolved_model or None,
+            )
+
+        try:
+            asyncio.run(_run())
+        except KeyboardInterrupt:
+            console.print("\n[yellow]Emailgen stopped.[/]")

decnet/orchestrator/drivers/email.py

@@ -0,0 +1,272 @@
+"""Email driver — Ollama-backed EML generation + decky-side delivery.
+
+One :class:`EmailAction` becomes one EML written into the mail decky's
+configured emailgen spool directory (``/var/spool/decnet-emails/`` by
+default).  An integration follow-up wires the IMAP/POP3 service templates
+to read EMLs from that spool at request time so attackers see the
+generated mail in their MUA.
+
+The Ollama call shells out via ``ollama run <model>`` — the prototype at
+``DECNET-EMAILs/main.py`` proved the round-trip works.  Output is
+parsed-and-repaired into a valid EML using :mod:`email.mime.*`; the
+worker then ``docker exec``\\s a ``tee`` to drop the file inside the
+target container.
+
+Per CLAUDE.md "no shell strings": every subprocess invocation uses an
+argv list, never ``shell=True``.  Ollama prompts and EML payloads are
+piped via ``stdin``, not interpolated into argv.
+"""
+from __future__ import annotations
+
+import asyncio
+import os
+import shlex
+import time
+from datetime import datetime, timezone
+from email.mime.text import MIMEText
+from email.utils import formatdate
+from typing import Any, Optional
+
+from decnet.logging import get_logger
+from decnet.orchestrator.drivers.base import ActivityResult
+from decnet.orchestrator.emailgen.prompt import PromptInputs, build as build_prompt
+from decnet.orchestrator.emailgen.scheduler import EmailAction
+from decnet.orchestrator.emailgen.threads import new_message_id
+
+log = get_logger("orchestrator.email")
+
+_DOCKER = "docker"
+_OLLAMA = "ollama"
+# Wall-clock cap for the LLM call.  Big enough for a 4070 running
+# llama3.1; small enough that a stuck Ollama server doesn't wedge the
+# emailgen tick.
+_DEFAULT_OLLAMA_TIMEOUT = float(os.environ.get("DECNET_EMAILGEN_TIMEOUT", "60"))
+_DEFAULT_MODEL = os.environ.get("DECNET_EMAILGEN_MODEL", "llama3.1")
+# docker-exec wall-clock cap for the per-EML write.
+_DOCKER_TIMEOUT = 8.0
+# Container suffix for the IMAP service on a mail decky.
+_IMAP_CONTAINER_SUFFIX = "-imap"
+_POP3_CONTAINER_SUFFIX = "-pop3"
+# Spool path inside the container.  Match the IMAP template's stubbed
+# IMAP_EMAIL_SEED location once wiring lands; shipping the constant now
+# lets that integration land independently.
+_SPOOL_DIR = "/var/spool/decnet-emails"
+
+
+async def _run_capture(
+    argv: list[str],
+    *,
+    stdin_data: Optional[bytes] = None,
+    timeout: float = _DOCKER_TIMEOUT,
+) -> tuple[int, str, str]:
+    """Spawn *argv*, optionally feeding *stdin_data*.  Never raises."""
+    try:
+        proc = await asyncio.create_subprocess_exec(
+            *argv,
+            stdin=asyncio.subprocess.PIPE if stdin_data is not None else None,
+            stdout=asyncio.subprocess.PIPE,
+            stderr=asyncio.subprocess.PIPE,
+        )
+    except FileNotFoundError as exc:
+        return 127, "", f"argv[0] not found: {exc}"
+    try:
+        stdout, stderr = await asyncio.wait_for(
+            proc.communicate(stdin_data), timeout=timeout,
+        )
+    except asyncio.TimeoutError:
+        try:
+            proc.kill()
+        except ProcessLookupError:
+            pass
+        return 124, "", "timeout"
+    return (
+        proc.returncode if proc.returncode is not None else -1,
+        stdout.decode("utf-8", "replace"),
+        stderr.decode("utf-8", "replace"),
+    )
+
+
+def _container_for(decky_name: str, services: list[str]) -> str:
+    """Pick the IMAP container if present, else POP3.  Names follow the
+    ``<decky_name>-<service>`` convention from the service templates."""
+    if "imap" in services:
+        return f"{decky_name}{_IMAP_CONTAINER_SUFFIX}"
+    return f"{decky_name}{_POP3_CONTAINER_SUFFIX}"
+
+
+def _parse_subject_and_body(ollama_output: str) -> tuple[str, str]:
+    """Split LLM output into (subject, body).
+
+    The prompt asks for ``Subject: <subject>\\n\\n<body>``.  When the
+    model misbehaves (e.g. wraps in markdown fences or skips the
+    Subject line), fall back to a generic subject and treat the whole
+    output as body.  Never raises.
+    """
+    text = ollama_output.strip()
+    # Strip code fences if the model wrapped output.
+    if text.startswith("```"):
+        nl = text.find("\n")
+        if nl > 0:
+            text = text[nl + 1:]
+        if text.endswith("```"):
+            text = text[: -3]
+        text = text.strip()
+    lines = text.splitlines()
+    if lines and lines[0].lower().startswith("subject:"):
+        subject = lines[0].split(":", 1)[1].strip()
+        # Drop the (possibly empty) blank line after Subject.
+        body_lines = lines[1:]
+        if body_lines and not body_lines[0].strip():
+            body_lines = body_lines[1:]
+        body = "\n".join(body_lines).strip()
+        if not subject:
+            subject = "Business Communication"
+        return subject, body
+    return "Business Communication", text
+
+
+def _build_eml(
+    *,
+    sender_name: str,
+    sender_email: str,
+    recipient_name: str,
+    recipient_email: str,
+    subject: str,
+    body: str,
+    message_id: str,
+    in_reply_to: Optional[str],
+    references: str,
+    ts: datetime,
+) -> bytes:
+    """Assemble a valid plain-text RFC 2822 EML."""
+    msg = MIMEText(body, "plain", "utf-8")
+    msg["From"] = f"{sender_name} <{sender_email}>"
+    msg["To"] = f"{recipient_name} <{recipient_email}>"
+    msg["Subject"] = subject
+    msg["Date"] = formatdate(ts.timestamp(), localtime=False)
+    msg["Message-ID"] = message_id
+    if in_reply_to:
+        msg["In-Reply-To"] = in_reply_to
+    if references:
+        msg["References"] = references
+    msg["MIME-Version"] = "1.0"
+    return msg.as_bytes()
+
+
+class EmailDriver:
+    """Concrete driver for :class:`EmailAction`.
+
+    Stateless across calls — Ollama model + timeout are constructor
+    args, not per-call.  The driver does *not* know about the bus or
+    DB; it returns an :class:`ActivityResult` that the worker pipes
+    onward.
+    """
+
+    def __init__(
+        self,
+        *,
+        model: str = _DEFAULT_MODEL,
+        ollama_timeout: float = _DEFAULT_OLLAMA_TIMEOUT,
+        spool_dir: str = _SPOOL_DIR,
+    ) -> None:
+        self.model = model
+        self.ollama_timeout = ollama_timeout
+        self.spool_dir = spool_dir
+
+    async def run(self, action: EmailAction) -> ActivityResult:
+        # Look up the mail-decky container name + services.  The driver
+        # receives a denormalised view via the action — the worker
+        # populates it from the same list the scheduler used.
+        return await self._run_email(action)
+
+    async def _run_email(self, action: EmailAction) -> ActivityResult:
+        t0 = time.monotonic()
+        prompt, mannerisms_used = build_prompt(
+            PromptInputs(
+                sender=action.sender,
+                recipient=action.recipient,
+                context_hint=action.context_hint,
+                parent_subject=action.subject_hint,
+                parent_excerpt=action.parent_excerpt,
+            )
+        )
+        rc, stdout, stderr = await _run_capture(
+            [_OLLAMA, "run", self.model],
+            stdin_data=prompt.encode("utf-8"),
+            timeout=self.ollama_timeout,
+        )
+        gen_ms = int((time.monotonic() - t0) * 1000)
+        if rc != 0 or not stdout.strip():
+            log.warning(
+                "emailgen ollama failed rc=%d stderr=%r model=%s",
+                rc, stderr[:200], self.model,
+            )
+            return ActivityResult(
+                success=False,
+                payload={
+                    "stage": "ollama",
+                    "rc": rc,
+                    "stderr": stderr.strip()[:256],
+                    "generation_ms": gen_ms,
+                    "model": self.model,
+                    "thread_id": action.thread_id,
+                },
+            )
+
+        subject, body = _parse_subject_and_body(stdout)
+        message_id = new_message_id(action.sender.email.split("@", 1)[1])
+        ts = datetime.now(timezone.utc)
+        eml_bytes = _build_eml(
+            sender_name=action.sender.name,
+            sender_email=action.sender.email,
+            recipient_name=action.recipient.name,
+            recipient_email=action.recipient.email,
+            subject=subject,
+            body=body,
+            message_id=message_id,
+            in_reply_to=action.parent_message_id,
+            references=action.references,
+            ts=ts,
+        )
+
+        # Drop the EML into the mail decky's spool dir over docker exec.
+        # File path: <spool>/<thread_id>/<uuid-from-message-id>.eml.
+        # Per-thread sub-directory keeps `ls` in the spool readable by
+        # operators inspecting the running decoy.
+        eml_filename = message_id.strip("<>").replace("@", "_at_") + ".eml"
+        eml_dir = f"{self.spool_dir.rstrip('/')}/{action.thread_id}"
+        eml_path = f"{eml_dir}/{eml_filename}"
+        container = _container_for(
+            action.mail_decky_name, list(action.mail_decky_services),
+        )
+        sh_cmd = (
+            f"mkdir -p {shlex.quote(eml_dir)} && "
+            f"tee {shlex.quote(eml_path)} >/dev/null"
+        )
+        argv = [_DOCKER, "exec", "-i", container, "sh", "-c", sh_cmd]
+        rc2, _stdout2, stderr2 = await _run_capture(
+            argv, stdin_data=eml_bytes, timeout=_DOCKER_TIMEOUT,
+        )
+        success = rc2 == 0
+        payload: dict[str, Any] = {
+            "stage": "delivered" if success else "delivery",
+            "model": self.model,
+            "generation_ms": gen_ms,
+            "bytes": len(eml_bytes),
+            "thread_id": action.thread_id,
+            "message_id": message_id,
+            "subject": subject,
+            "language": action.sender.language or "en",
+            "mannerisms_used": mannerisms_used,
+            "is_reply": action.is_reply,
+            "container": container,
+            "eml_path": eml_path,
+            "rc": rc2,
+            "stderr": stderr2.strip()[:256] if not success else None,
+        }
+        if not success:
+            log.warning(
+                "emailgen delivery failed container=%s rc=%d stderr=%r",
+                container, rc2, stderr2[:200],
+            )
+        return ActivityResult(success=success, payload=payload)

decnet/orchestrator/emailgen/__init__.py

@@ -0,0 +1,33 @@
+"""Emailgen — second orchestrator worker.
+
+Generates fake corporate emails (multi-language, threaded, persona-driven)
+and drops them into mail-decky maildirs so attackers landing on
+IMAP/POP3 honeypots find believable mailboxes instead of empty inboxes.
+
+The module is intentionally a sibling of :mod:`decnet.orchestrator` (not
+a flag on it) — separate worker, separate CLI command
+(``decnet emailgen``), separate systemd-supervised lifecycle. Shares the
+heartbeat / control-listener scaffolding via :mod:`decnet.bus.publish`.
+
+Lazy worker re-export: :func:`emailgen_worker` is loaded on first
+attribute access so that submodules can import package-level names
+(``decnet.orchestrator.emailgen.prompt``) without triggering an eager
+load of the worker — and through it, the email driver, which imports
+back into this package.  Without lazy loading the package + driver +
+worker form a cycle.
+"""
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any
+
+if TYPE_CHECKING:  # pragma: no cover - typing only
+    from decnet.orchestrator.emailgen.worker import emailgen_worker  # noqa: F401
+
+__all__ = ["emailgen_worker"]
+
+
+def __getattr__(name: str) -> Any:
+    if name == "emailgen_worker":
+        from decnet.orchestrator.emailgen.worker import emailgen_worker as _w
+        return _w
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")

decnet/orchestrator/emailgen/events.py

@@ -0,0 +1,49 @@
+"""DB-row + bus-topic helpers for the emailgen worker.
+
+Mirror of :mod:`decnet.orchestrator.events` for the email action class.
+Kept in its own module so the SSH-flavoured orchestrator and the
+emailgen worker don't accumulate cross-imports of each other's action
+types.
+"""
+from __future__ import annotations
+
+from datetime import datetime, timezone
+from typing import Any
+
+from decnet.bus import topics as _topics
+from decnet.orchestrator.drivers.base import ActivityResult
+from decnet.orchestrator.emailgen.scheduler import EmailAction
+
+
+def to_row(action: EmailAction, result: ActivityResult) -> dict[str, Any]:
+    """Build the kwargs dict for ``OrchestratorEmail(**...)``.
+
+    Pulls ``message_id`` / ``subject`` / ``language`` out of the
+    driver's ``payload`` rather than off the action — the EML's
+    Message-ID is generated inside the driver after the LLM call so
+    we know it matches what landed on disk.
+    """
+    payload = result.payload or {}
+    return {
+        "ts": datetime.now(timezone.utc),
+        "mail_decky_uuid": action.mail_decky_uuid,
+        "thread_id": action.thread_id,
+        "message_id": payload.get("message_id", ""),
+        "in_reply_to": action.parent_message_id,
+        "sender_email": action.sender.email,
+        "recipient_email": action.recipient.email,
+        "subject": payload.get("subject", ""),
+        "language": payload.get("language", action.sender.language or "en"),
+        "eml_path": payload.get("eml_path", ""),
+        "success": result.success,
+        "payload": payload,    # repo serialises dict→json
+    }
+
+
+def topic_for(action: EmailAction) -> str:
+    """Map an email action to its bus topic."""
+    return _topics.orchestrator(_topics.ORCHESTRATOR_EMAIL, action.mail_decky_uuid)
+
+
+def event_type_for(action: EmailAction) -> str:    # noqa: ARG001 — symmetry
+    return _topics.ORCHESTRATOR_EMAIL

decnet/orchestrator/emailgen/personas.py

@@ -0,0 +1,119 @@
+"""Persona schema for the emailgen worker.
+
+Stored as a JSON list on :attr:`Topology.email_personas`.  Each persona
+describes one fictional employee whose mailbox lives on the topology's
+IMAP/POP3 decky.  The schema deliberately stays narrow: the LLM gets
+*enough* differentiation to write distinct voices, no more.
+
+Invalid entries are dropped with a warning (returned alongside the
+parsed list) rather than raising — a single typo in one persona must
+not stall the entire emailgen tick.
+"""
+from __future__ import annotations
+
+import json
+from typing import Literal, Optional
+
+from pydantic import BaseModel, Field, ValidationError, field_validator
+
+from decnet.logging import get_logger
+
+logger = get_logger("orchestrator.emailgen")
+
+Tone = Literal["formal", "direct", "casual", "technical"]
+ReplyLatency = Literal["fast", "normal", "slow"]
+
+
+class EmailPersona(BaseModel):
+    """One fake mailbox owner.
+
+    ``language`` is ISO 639-1 (``en``, ``es``, ``pt``…); when unset on the
+    persona it falls back to the topology's ``language_default``.
+    ``uses_llms_heavily`` lifts the prompt-layer em-dash suppression for
+    that persona — em-dashes are an LLM tell, but a persona explicitly
+    pegged as a heavy LLM user should *naturally* produce them.
+    """
+    name: str = Field(min_length=1, max_length=128)
+    email: str = Field(min_length=3, max_length=255)
+    role: str = Field(min_length=1, max_length=128)
+    tone: Tone = "formal"
+    mannerisms: list[str] = Field(default_factory=list, max_length=12)
+    language: Optional[str] = Field(default=None, max_length=8)
+    signature: Optional[str] = Field(default=None, max_length=512)
+    active_hours: str = Field(default="09:00-18:00", max_length=32)
+    reply_latency: ReplyLatency = "normal"
+    uses_llms_heavily: bool = False
+
+    @field_validator("email")
+    @classmethod
+    def _email_shape(cls, v: str) -> str:
+        # Cheap structural check — full RFC 5322 isn't worth the
+        # dependency.  We only need ``user@domain`` with non-empty parts
+        # for the prompt builder + Message-ID generator.
+        if "@" not in v:
+            raise ValueError("email must contain '@'")
+        local, _, domain = v.rpartition("@")
+        if not local or not domain or "." not in domain:
+            raise ValueError("email must look like user@domain.tld")
+        return v
+
+
+def parse_personas(
+    raw: str | list | None,
+    *,
+    language_default: str = "en",
+) -> list[EmailPersona]:
+    """Parse the JSON-or-list ``email_personas`` value into models.
+
+    Resolves ``language`` against *language_default* so downstream
+    consumers (prompt builder, scheduler) never need to know about
+    fallback semantics.
+    """
+    if not raw:
+        return []
+    if isinstance(raw, str):
+        try:
+            raw = json.loads(raw)
+        except json.JSONDecodeError as exc:
+            logger.warning("emailgen personas: invalid JSON, skipping: %s", exc)
+            return []
+    if not isinstance(raw, list):
+        logger.warning(
+            "emailgen personas: expected list, got %s", type(raw).__name__
+        )
+        return []
+    out: list[EmailPersona] = []
+    for i, entry in enumerate(raw):
+        try:
+            persona = EmailPersona.model_validate(entry)
+        except ValidationError as exc:
+            logger.warning(
+                "emailgen personas: dropping invalid entry index=%d: %s",
+                i, exc.errors(include_url=False),
+            )
+            continue
+        if persona.language is None:
+            persona = persona.model_copy(update={"language": language_default})
+        out.append(persona)
+    return out
+
+
+def in_active_hours(persona: EmailPersona, now_hour: int) -> bool:
+    """Return True if *now_hour* (0–23) falls in the persona's window.
+
+    Format: ``"HH:MM-HH:MM"``. Wrap-around windows (``"22:00-06:00"``)
+    are supported. Invalid windows treat the persona as always-on so a
+    config typo never silences the whole fleet.
+    """
+    try:
+        start_s, end_s = persona.active_hours.split("-")
+        start_h = int(start_s.split(":")[0])
+        end_h = int(end_s.split(":")[0])
+    except (ValueError, IndexError):
+        return True
+    if start_h == end_h:
+        return True
+    if start_h < end_h:
+        return start_h <= now_hour < end_h
+    # Wrap-around (e.g. 22:00-06:00).
+    return now_hour >= start_h or now_hour < end_h

decnet/orchestrator/emailgen/prompt.py

@@ -0,0 +1,151 @@
+"""Ollama prompt builder for emailgen.
+
+The LLM gets a tightly-scoped instruction and a small handful of
+deterministic constraints.  Persona mannerisms are *pre-selected* in
+Python (1–2 of the persona's full list) and injected as hard rules —
+small models otherwise treat the mannerism list as flavour text and
+ignore it, and the corpus collapses into one voice.
+
+**Em-dash suppression** is on by default; suppression is lifted only
+for personas that opt in via ``uses_llms_heavily``.  Em-dashes are a
+strong stylometric tell for LLM-authored prose, and a honeypot mailbox
+where every author uses them is a tell.
+"""
+from __future__ import annotations
+
+import secrets
+from dataclasses import dataclass
+from typing import Optional
+
+from decnet.orchestrator.emailgen.personas import EmailPersona
+
+
+@dataclass(frozen=True)
+class PromptInputs:
+    sender: EmailPersona
+    recipient: EmailPersona
+    context_hint: str
+    parent_subject: Optional[str] = None      # set when replying
+    parent_excerpt: Optional[str] = None      # short snippet of last msg
+
+
+_LANGUAGE_NAMES = {
+    "en": "English",
+    "es": "Spanish",
+    "pt": "Portuguese",
+    "fr": "French",
+    "de": "German",
+    "it": "Italian",
+    "nl": "Dutch",
+    "ja": "Japanese",
+    "zh": "Chinese",
+}
+
+
+def _lang_label(code: str) -> str:
+    return _LANGUAGE_NAMES.get(code.lower(), code)
+
+
+def select_mannerisms(
+    persona: EmailPersona,
+    *,
+    rng: Optional[secrets.SystemRandom] = None,
+    n: int = 2,
+) -> list[str]:
+    """Pick *n* mannerisms deterministically given *rng*.
+
+    Returns up to *n*; falls back to the full list when the persona
+    declares fewer.  Determinism (under a seeded RNG) is what makes
+    tests practical — otherwise mannerism injection is unverifiable.
+    """
+    rnd = rng or secrets.SystemRandom()
+    pool = list(persona.mannerisms)
+    if not pool:
+        return []
+    if len(pool) <= n:
+        return pool
+    rnd.shuffle(pool)
+    return pool[:n]
+
+
+def build(
+    inputs: PromptInputs,
+    *,
+    rng: Optional[secrets.SystemRandom] = None,
+) -> tuple[str, list[str]]:
+    """Return ``(prompt, mannerisms_used)``.
+
+    ``mannerisms_used`` flows back into the persisted ``payload`` JSON
+    so an analyst can see *why* a given email reads the way it does.
+    """
+    sender = inputs.sender
+    recipient = inputs.recipient
+    language = _lang_label(sender.language or "en")
+    mannerisms = select_mannerisms(sender, rng=rng)
+    mannerism_block = (
+        "\n".join(f"- {m}" for m in mannerisms)
+        if mannerisms
+        else "- (no specific mannerisms; write in the persona's tone)"
+    )
+
+    if sender.uses_llms_heavily:
+        em_dash_rule = (
+            "Em-dashes are fine — this persona uses them naturally. "
+            "Write in your usual style."
+        )
+    else:
+        em_dash_rule = (
+            "Do NOT use em-dashes (—). Use commas, periods, or "
+            "parentheses instead. Em-dashes are a tell."
+        )
+
+    sig_block = (
+        f"Use this exact signature block:\n{sender.signature}"
+        if sender.signature
+        else "End with a short, plausible signature for the persona's role."
+    )
+
+    if inputs.parent_subject:
+        thread_block = (
+            f"This is a REPLY in an ongoing thread.\n"
+            f"- Parent subject: {inputs.parent_subject}\n"
+            f"- Parent excerpt: {inputs.parent_excerpt or '(no excerpt)'}\n"
+            f"- Begin the body assuming the recipient already read the parent.\n"
+        )
+        subject_rule = (
+            "Subject must be the parent subject prefixed with 'Re: ' "
+            "(no double 'Re: Re:')."
+        )
+    else:
+        thread_block = "This is a NEW thread (no prior context)."
+        subject_rule = (
+            "Generate a short, specific subject line (≤ 80 chars) "
+            "appropriate to the context."
+        )
+
+    prompt = f"""You are writing one corporate email, RFC 2822 plain-text body only.
+
+Persona — sender:
+- Name: {sender.name}
+- Role: {sender.role}
+- Tone: {sender.tone}
+- Mannerisms (must show through):
+{mannerism_block}
+
+Persona — recipient:
+- Name: {recipient.name}
+- Role: {recipient.role}
+
+Context hint: {inputs.context_hint}
+
+Thread context:
+{thread_block}
+
+Hard rules:
+1. Write the email body in {language}. Do not translate or code-switch.
+2. {em_dash_rule}
+3. {subject_rule}
+4. {sig_block}
+5. Output ONLY the email — first line is "Subject: <subject>", then a blank line, then the body. No commentary, no markdown fences, no preamble.
+"""
+    return prompt.strip(), mannerisms

decnet/orchestrator/emailgen/scheduler.py

@@ -0,0 +1,228 @@
+"""Action picker for the emailgen worker.
+
+One tick = one (mail-decky, sender, recipient, [thread]) decision.
+
+Scope (v1):
+- Only TopologyDeckies are eligible mail hosts. Fleet / SWARM-shard
+  mail-deckies are out of scope per the plan; they get covered when the
+  forwarder pattern lands for emailgen.
+- Mail decky = a running TopologyDecky whose ``services`` includes
+  ``imap`` or ``pop3``.
+- Personas come from ``Topology.email_personas`` (JSON list of
+  :class:`EmailPersona`).  Topology-wide ``language_default`` fills in
+  any persona that didn't set its own.
+
+Returns ``None`` (skip tick) when:
+- no running mail decky,
+- the mail decky's topology has fewer than two valid personas,
+- nobody is in their ``active_hours`` window right now.
+"""
+from __future__ import annotations
+
+import secrets
+from dataclasses import dataclass
+from datetime import datetime
+from typing import Any, Optional
+
+from decnet.logging import get_logger
+from decnet.orchestrator.emailgen.personas import (
+    EmailPersona,
+    in_active_hours,
+    parse_personas,
+)
+from decnet.orchestrator.emailgen.threads import (
+    ThreadChain,
+    new_thread_id,
+    references_for_reply,
+    reply_subject,
+)
+
+logger = get_logger("orchestrator.emailgen")
+
+_MAIL_SERVICES = ("imap", "pop3")
+# Probability of replying on an existing thread when one exists.  The
+# inverse starts a fresh thread.  0.6 mirrors what mailbox studies find
+# for active corporate inboxes — most messages are replies, but not
+# overwhelmingly so.
+_REPLY_PROBABILITY = 0.6
+
+# Generic context hints fed to the LLM when starting a new thread.
+# Deliberately broad — the persona's tone + role is what shapes the
+# email; the hint just gives the model a topic to riff on.
+_CONTEXT_HINTS: tuple[str, ...] = (
+    "Q3 budget review and approval",
+    "Client presentation feedback",
+    "Project deadline extension request",
+    "Team building event planning",
+    "IT system maintenance notification",
+    "Quarterly performance review",
+    "Vendor onboarding process",
+    "Holiday schedule announcement",
+    "Training session invitation",
+    "Department restructuring update",
+    "Client contract negotiation",
+    "Security audit findings",
+    "Sales strategy meeting",
+    "Product launch timeline",
+    "Office relocation update",
+    "Travel reimbursement policy change",
+)
+
+
+@dataclass(frozen=True)
+class EmailAction:
+    """One emailgen tick's decision.
+
+    ``thread_id`` is non-None whenever this action is a reply; the
+    worker writes it back to the DB so future ticks can chain further
+    replies.  ``in_reply_to`` / ``references`` mirror the RFC 2822
+    headers we'll set on the EML.
+
+    ``mail_decky_name`` / ``mail_decky_services`` are denormalised onto
+    the action so the driver doesn't need a second repo round-trip just
+    to resolve the container name.
+    """
+    mail_decky_uuid: str
+    mail_decky_name: str
+    mail_decky_services: tuple[str, ...]
+    sender: EmailPersona
+    recipient: EmailPersona
+    thread_id: str
+    parent_message_id: Optional[str]
+    references: str
+    subject_hint: Optional[str]      # used as parent subject when replying
+    parent_excerpt: Optional[str]    # excerpt from the parent body
+    context_hint: str                # only meaningful on new threads
+    is_reply: bool
+    description: str = "email:send"
+
+
+def _is_mail_decky(decky: dict[str, Any]) -> bool:
+    services = decky.get("services") or []
+    if isinstance(services, str):
+        return False
+    return any(s in services for s in _MAIL_SERVICES)
+
+
+async def pick(
+    repo: Any,
+    *,
+    rand: Optional[secrets.SystemRandom] = None,
+    now: Optional[datetime] = None,
+) -> Optional[EmailAction]:
+    """Pick one email action against the running fleet.
+
+    *repo* is a :class:`BaseRepository`; we fetch running topology
+    deckies + their parent topology row directly. *now* is the
+    wall-clock used for ``active_hours`` filtering — injected so tests
+    can pin the hour deterministically.
+    """
+    rng = rand or secrets.SystemRandom()
+    now_dt = now or datetime.now()
+
+    deckies = await repo.list_running_topology_deckies()
+    mail_deckies = [d for d in deckies if _is_mail_decky(d)]
+    if not mail_deckies:
+        logger.debug("emailgen pick: no running mail decky")
+        return None
+
+    mail_decky = rng.choice(mail_deckies)
+    topology_id = mail_decky.get("topology_id")
+    if not topology_id:
+        logger.debug("emailgen pick: mail decky has no topology_id")
+        return None
+
+    topology = await repo.get_topology(topology_id)
+    if not topology:
+        logger.debug("emailgen pick: topology %s not found", topology_id)
+        return None
+
+    personas = parse_personas(
+        topology.get("email_personas"),
+        language_default=topology.get("language_default") or "en",
+    )
+    if len(personas) < 2:
+        logger.debug(
+            "emailgen pick: topology=%s has only %d personas; need >=2",
+            topology_id, len(personas),
+        )
+        return None
+
+    active = [p for p in personas if in_active_hours(p, now_dt.hour)]
+    if len(active) < 2:
+        logger.debug(
+            "emailgen pick: topology=%s only %d personas in-hours",
+            topology_id, len(active),
+        )
+        return None
+
+    sender = rng.choice(active)
+    recipient = rng.choice([p for p in active if p.email != sender.email])
+
+    # Look up open threads between this pair on this mail decky.
+    chain = await _maybe_pick_chain(
+        repo, mail_decky["uuid"], sender, recipient, rng=rng,
+    )
+
+    services = tuple(mail_decky.get("services") or ())
+    decky_name = mail_decky.get("name") or ""
+
+    if chain is not None:
+        return EmailAction(
+            mail_decky_uuid=mail_decky["uuid"],
+            mail_decky_name=decky_name,
+            mail_decky_services=services,
+            sender=sender,
+            recipient=recipient,
+            thread_id=chain.thread_id,
+            parent_message_id=chain.parent_message_id,
+            references=references_for_reply(chain),
+            subject_hint=chain.parent_subject,
+            parent_excerpt=None,    # repo can populate later if useful
+            context_hint=chain.parent_subject,
+            is_reply=True,
+        )
+
+    return EmailAction(
+        mail_decky_uuid=mail_decky["uuid"],
+        mail_decky_name=decky_name,
+        mail_decky_services=services,
+        sender=sender,
+        recipient=recipient,
+        thread_id=new_thread_id(),
+        parent_message_id=None,
+        references="",
+        subject_hint=None,
+        parent_excerpt=None,
+        context_hint=rng.choice(_CONTEXT_HINTS),
+        is_reply=False,
+    )
+
+
+async def _maybe_pick_chain(
+    repo: Any,
+    mail_decky_uuid: str,
+    sender: EmailPersona,
+    recipient: EmailPersona,
+    *,
+    rng: secrets.SystemRandom,
+) -> Optional[ThreadChain]:
+    """Probabilistically pick an open thread between the pair, or None."""
+    if rng.random() >= _REPLY_PROBABILITY:
+        return None
+    threads = await repo.list_orchestrator_email_threads(
+        mail_decky_uuid, sender.email, recipient.email, limit=20,
+    )
+    if not threads:
+        return None
+    head = threads[0]
+    return ThreadChain(
+        thread_id=head["thread_id"],
+        parent_message_id=head["message_id"],
+        # We don't reconstruct the full ancestry from row history here —
+        # the parent's References + parent's Message-ID would do that.
+        # For v1, single-step references is fine; mail clients still
+        # group correctly by (Subject + In-Reply-To).
+        references=tuple(),
+        parent_subject=reply_subject(head["subject"]),
+    )

decnet/orchestrator/emailgen/threads.py

@@ -0,0 +1,75 @@
+"""RFC 2822 thread-chain bookkeeping.
+
+A thread is a worker-side UUID that groups one or more emails between
+the same two personas.  ``In-Reply-To`` carries the immediate parent's
+``Message-ID``; ``References`` carries the full ancestry chain.
+
+The emailgen scheduler queries the repository for the most recent email
+in any thread between (sender, recipient); if it finds one, it emits a
+reply (continuing the chain).  Otherwise it starts a new thread.
+"""
+from __future__ import annotations
+
+import uuid
+from dataclasses import dataclass
+from typing import Optional
+
+
+@dataclass(frozen=True)
+class ThreadChain:
+    """Immutable view of a thread's chain at a point in time.
+
+    ``thread_id`` is opaque (UUID).  ``parent_message_id`` is the most
+    recent message in the chain — the new reply's ``In-Reply-To`` field.
+    ``references`` is the dot-separated history fed into the
+    ``References:`` header (oldest-first per RFC 2822 §3.6.4).
+    ``parent_subject`` carries the subject we're replying to, so the
+    reply can prepend ``Re:`` correctly.
+    """
+    thread_id: str
+    parent_message_id: str
+    references: tuple[str, ...]
+    parent_subject: str
+
+
+def new_thread_id() -> str:
+    return str(uuid.uuid4())
+
+
+def reply_subject(parent_subject: str) -> str:
+    """Prepend ``Re:`` to *parent_subject* if not already a reply.
+
+    Folds repeat ``Re: Re: Re:`` into a single ``Re:`` — Outlook /
+    Thunderbird both do this and an attacker reading the maildir would
+    notice the corpus's missing convention immediately.
+    """
+    s = parent_subject.strip()
+    lowered = s.lower()
+    while lowered.startswith("re:"):
+        s = s[3:].lstrip()
+        lowered = s.lower()
+    return f"Re: {s}"
+
+
+def references_for_reply(chain: Optional[ThreadChain]) -> str:
+    """Build the ``References:`` header value for a reply.
+
+    Returns a space-separated list of message-ids, oldest-first, with
+    the parent appended.  Empty string when *chain* is None (root).
+    """
+    if chain is None:
+        return ""
+    refs = list(chain.references) + [chain.parent_message_id]
+    return " ".join(refs)
+
+
+def new_message_id(domain: str) -> str:
+    """Build an RFC 2822 ``Message-ID`` value (incl. angle brackets).
+
+    Worker side — the value is also stored in the DB so a future reply
+    can be threaded against it.  Domain mirrors the sender's email
+    domain so an attacker grepping for tells doesn't find every
+    fake-corp email tagged with ``@example.com``.
+    """
+    safe_domain = domain.strip() or "localhost"
+    return f"<{uuid.uuid4().hex}@{safe_domain}>"

decnet/orchestrator/emailgen/worker.py

@@ -0,0 +1,131 @@
+"""Emailgen main loop.
+
+Mirrors :mod:`decnet.orchestrator.worker` shape: same heartbeat, same
+control listener, same fire-and-forget bus publish, same prune knob.
+A wedged ollama call stalls only this worker, never the SSH-flavoured
+orchestrator running alongside.
+"""
+from __future__ import annotations
+
+import asyncio
+import contextlib
+
+from decnet.bus.factory import get_bus
+from decnet.bus.publish import (
+    publish_safely,
+    run_control_listener,
+    run_health_heartbeat,
+)
+from decnet.logging import get_logger
+from decnet.orchestrator.drivers.email import EmailDriver
+from decnet.orchestrator.emailgen import events, scheduler
+from decnet.web.db.repository import BaseRepository
+
+logger = get_logger("orchestrator.emailgen")
+
+# Periodic-prune knobs — same shape as orchestrator/worker.py.
+_PRUNE_EVERY_TICKS = 100
+_PRUNE_PER_DECKY_CAP = 5000
+
+
+async def emailgen_worker(
+    repo: BaseRepository,
+    *,
+    interval: int = 300,
+    model: str | None = None,
+) -> None:
+    """Periodically generate one fake email into a running mail decky.
+
+    Default interval is 5 minutes — emails are expensive (LLM round
+    trip) and don't need to fire every minute to look natural.  Honors
+    ``system.emailgen.control`` for graceful shutdown.
+    """
+    logger.info("emailgen worker started interval=%ds model=%s", interval, model)
+
+    bus = None
+    try:
+        bus = get_bus(client_name="emailgen")
+        await bus.connect()
+    except Exception as exc:  # noqa: BLE001
+        logger.warning(
+            "emailgen: bus unavailable, continuing without publish: %s", exc
+        )
+        bus = None
+
+    driver = EmailDriver(model=model) if model else EmailDriver()
+    shutdown = asyncio.Event()
+    heartbeat_task = asyncio.create_task(run_health_heartbeat(bus, "emailgen"))
+    control_task = asyncio.create_task(
+        run_control_listener(bus, "emailgen", shutdown),
+    )
+    tick_n = 0
+    try:
+        while not shutdown.is_set():
+            try:
+                await asyncio.wait_for(shutdown.wait(), timeout=interval)
+            except asyncio.TimeoutError:
+                pass  # normal tick
+            if shutdown.is_set():
+                break
+            try:
+                await _one_tick(repo, driver, bus)
+            except Exception as exc:  # noqa: BLE001
+                logger.error("emailgen tick failed: %s", exc)
+            tick_n += 1
+            if tick_n % _PRUNE_EVERY_TICKS == 0:
+                try:
+                    deleted = await repo.prune_orchestrator_emails(
+                        per_decky_cap=_PRUNE_PER_DECKY_CAP,
+                    )
+                    if deleted:
+                        logger.info(
+                            "emailgen prune deleted=%d cap=%d",
+                            deleted, _PRUNE_PER_DECKY_CAP,
+                        )
+                except Exception as exc:  # noqa: BLE001
+                    logger.error("emailgen prune failed: %s", exc)
+    finally:
+        for t in (heartbeat_task, control_task):
+            t.cancel()
+            with contextlib.suppress(Exception, asyncio.CancelledError):
+                await t
+        if bus is not None:
+            with contextlib.suppress(Exception):
+                await bus.close()
+
+
+async def _one_tick(repo: BaseRepository, driver: EmailDriver, bus) -> None:
+    action = await scheduler.pick(repo)
+    if action is None:
+        logger.debug("emailgen: no actionable mail decky / personas this tick")
+        return
+
+    result = await driver.run(action)
+    row = events.to_row(action, result)
+    await repo.record_orchestrator_email(row)
+
+    if bus is not None:
+        topic = events.topic_for(action)
+        # Mirror the orchestrator-event SSE-friendly payload shape: ts
+        # as iso8601, payload as already-serialised dict.
+        bus_payload = {
+            "kind": "email",
+            "mail_decky_uuid": row["mail_decky_uuid"],
+            "thread_id": row["thread_id"],
+            "message_id": row["message_id"],
+            "in_reply_to": row["in_reply_to"],
+            "sender_email": row["sender_email"],
+            "recipient_email": row["recipient_email"],
+            "subject": row["subject"],
+            "language": row["language"],
+            "success": row["success"],
+            "ts": row["ts"].isoformat(),
+        }
+        await publish_safely(
+            bus, topic, bus_payload, event_type=events.event_type_for(action),
+        )
+
+    logger.info(
+        "emailgen tick mail_decky=%s thread=%s success=%s reply=%s",
+        row["mail_decky_uuid"], row["thread_id"], row["success"], action.is_reply,
+    )

decnet/web/db/models/__init__.py

@@ -58,6 +58,8 @@ from .health import (
     HealthResponse,
 )
 from .orchestrator import (
+    OrchestratorEmail,
+    OrchestratorEmailsResponse,
     OrchestratorEvent,
     OrchestratorEventsResponse,
 )
@@ -193,6 +195,8 @@ __all__ = [
     "ComponentHealth",
     "HealthResponse",
     # orchestrator
+    "OrchestratorEmail",
+    "OrchestratorEmailsResponse",
     "OrchestratorEvent",
     "OrchestratorEventsResponse",
     # logs

decnet/web/db/models/orchestrator.py

@@ -60,3 +60,52 @@ class OrchestratorEventsResponse(BaseModel):
     limit: int
     offset: int
     data: List[dict[str, Any]]
+
+
+class OrchestratorEmail(SQLModel, table=True):
+    """One fake email generated by the ``decnet emailgen`` worker.
+
+    Sibling table to :class:`OrchestratorEvent` — kept disjoint because
+    email rows carry domain-specific fields (subject, message_id,
+    in_reply_to, language) that have no analogue in the SSH/file events
+    and would otherwise bloat ``OrchestratorEvent.payload``.
+
+    The mail decky's UUID lives in ``mail_decky_uuid`` (the host serving
+    the IMAP/POP3 mailbox).  ``thread_id`` is a worker-side UUID used to
+    chain replies; ``in_reply_to`` is the parent email's RFC 2822
+    Message-ID header value (or ``None`` for thread roots).
+
+    ``payload`` follows the same loose-JSON convention as
+    :class:`OrchestratorEvent`: ``bytes``, ``generation_ms``, ``model``,
+    ``mannerisms_used``, etc.  The worker can extend it without a
+    migration.
+    """
+    __tablename__ = "orchestrator_emails"
+    __table_args__ = (
+        Index("ix_orchestrator_emails_mail_ts", "mail_decky_uuid", "ts"),
+        Index("ix_orchestrator_emails_thread", "thread_id"),
+    )
+    uuid: str = Field(default_factory=lambda: str(uuid4()), primary_key=True)
+    ts: datetime = Field(
+        default_factory=lambda: datetime.now(timezone.utc), index=True
+    )
+    mail_decky_uuid: str = Field(index=True)
+    thread_id: str = Field(index=True)
+    message_id: str = Field(max_length=255)
+    in_reply_to: Optional[str] = Field(default=None, max_length=255)
+    sender_email: str = Field(max_length=255, index=True)
+    recipient_email: str = Field(max_length=255, index=True)
+    subject: str = Field(max_length=512)
+    language: str = Field(max_length=8, default="en")
+    eml_path: str = Field(max_length=1024)
+    success: bool = Field(default=False, index=True)
+    payload: str = Field(
+        sa_column=Column("payload", Text, nullable=False, default="{}")
+    )
+
+
+class OrchestratorEmailsResponse(BaseModel):
+    total: int
+    limit: int
+    offset: int
+    data: List[dict[str, Any]]

decnet/web/db/models/topology.py

@@ -47,6 +47,18 @@ class Topology(SQLModel, table=True):
     # running.  Drained by the mutator watch loop, which re-pushes via
     # AgentClient and clears the flag.  NULL for unihost topologies.
     needs_resync: bool = Field(default=False, nullable=False)
+    # JSON-serialised list of EmailPersona dicts consumed by the
+    # ``decnet emailgen`` worker.  Empty list = no fake mailbox owners
+    # configured for this topology, the worker skips it.
+    email_personas: str = Field(
+        sa_column=Column(
+            "email_personas", _BIG_TEXT, nullable=False, default="[]"
+        )
+    )
+    # ISO 639-1 language code applied to any persona that doesn't override
+    # ``language`` itself.  English by default; ANTI's deployments default
+    # to "es" by editing this column.
+    language_default: str = Field(default="en", max_length=8)
 
 
 class LAN(SQLModel, table=True):

decnet/web/db/repository.py

@@ -952,3 +952,57 @@ class BaseRepository(ABC):
         unbounded growth without paying the cost on every write.
         """
         raise NotImplementedError
+
+    async def record_orchestrator_email(self, data: dict[str, Any]) -> str:
+        """Insert one orchestrator-generated email row, returning its uuid."""
+        raise NotImplementedError
+
+    async def list_orchestrator_emails(
+        self,
+        limit: int = 100,
+        offset: int = 0,
+        *,
+        mail_decky_uuid: Optional[str] = None,
+        thread_id: Optional[str] = None,
+        since_ts: Optional[Any] = None,
+    ) -> list[dict[str, Any]]:
+        """Paginated orchestrator emails newest-first.
+
+        Optional filters narrow to a single mail decky or to one thread,
+        used by the dashboard's mailbox-inspector view.
+        """
+        raise NotImplementedError
+
+    async def count_orchestrator_emails(
+        self,
+        *,
+        mail_decky_uuid: Optional[str] = None,
+    ) -> int:
+        """Total orchestrator-email rows, optionally filtered by mail decky."""
+        raise NotImplementedError
+
+    async def list_orchestrator_email_threads(
+        self,
+        mail_decky_uuid: str,
+        sender_email: str,
+        recipient_email: str,
+        *,
+        limit: int = 50,
+    ) -> list[dict[str, Any]]:
+        """Open threads between *sender_email* and *recipient_email* on
+        *mail_decky_uuid*, newest-first.
+
+        Used by the emailgen scheduler to decide whether to start a new
+        thread or reply on an existing one.  Each entry is one row's
+        worth of dict — the worker only needs ``thread_id`` and the most
+        recent ``message_id`` / ``subject`` to build the reply.
+        """
+        raise NotImplementedError
+
+    async def prune_orchestrator_emails(self, per_decky_cap: int = 10000) -> int:
+        """Trim per-``mail_decky_uuid`` rows to a cap. Returns deleted count.
+
+        Mirrors :meth:`prune_orchestrator_events`; emailgen worker calls
+        this on a periodic tick.
+        """
+        raise NotImplementedError

decnet/web/db/sqlmodel_repo.py

@@ -51,6 +51,7 @@ from decnet.web.db.models import (
     TopologyEdge,
     TopologyStatusEvent,
     TopologyMutation,
+    OrchestratorEmail,
     OrchestratorEvent,
     WebhookSubscription,
 )
@@ -3003,3 +3004,113 @@ class SQLModelRepository(BaseRepository):
                 deleted += res.rowcount or 0
             await session.commit()
         return deleted
+
+    # ---------------------------------------------------------- emailgen
+
+    async def record_orchestrator_email(self, data: dict[str, Any]) -> str:
+        payload = data.get("payload")
+        if isinstance(payload, (dict, list)):
+            data = {**data, "payload": json.dumps(payload)}
+        async with self._session() as session:
+            row = OrchestratorEmail(**data)
+            session.add(row)
+            await session.commit()
+            await session.refresh(row)
+            return row.uuid
+
+    async def list_orchestrator_emails(
+        self,
+        limit: int = 100,
+        offset: int = 0,
+        *,
+        mail_decky_uuid: Optional[str] = None,
+        thread_id: Optional[str] = None,
+        since_ts: Optional[datetime] = None,
+    ) -> list[dict[str, Any]]:
+        async with self._session() as session:
+            stmt = select(OrchestratorEmail)
+            if mail_decky_uuid is not None:
+                stmt = stmt.where(
+                    OrchestratorEmail.mail_decky_uuid == mail_decky_uuid
+                )
+            if thread_id is not None:
+                stmt = stmt.where(OrchestratorEmail.thread_id == thread_id)
+            if since_ts is not None:
+                stmt = stmt.where(OrchestratorEmail.ts >= since_ts)
+            stmt = (
+                stmt.order_by(desc(OrchestratorEmail.ts))
+                .offset(offset)
+                .limit(limit)
+            )
+            result = await session.execute(stmt)
+            return [r.model_dump(mode="json") for r in result.scalars().all()]
+
+    async def count_orchestrator_emails(
+        self,
+        *,
+        mail_decky_uuid: Optional[str] = None,
+    ) -> int:
+        stmt = select(func.count()).select_from(OrchestratorEmail)
+        if mail_decky_uuid is not None:
+            stmt = stmt.where(OrchestratorEmail.mail_decky_uuid == mail_decky_uuid)
+        async with self._session() as session:
+            result = await session.execute(stmt)
+            return result.scalar() or 0
+
+    async def list_orchestrator_email_threads(
+        self,
+        mail_decky_uuid: str,
+        sender_email: str,
+        recipient_email: str,
+        *,
+        limit: int = 50,
+    ) -> list[dict[str, Any]]:
+        # Most-recent row per (sender, recipient) pair under this mail decky.
+        # The scheduler only needs the latest message_id/subject/thread_id to
+        # construct a reply; older rows in the same thread aren't relevant
+        # for the "do we reply or start fresh" decision.
+        async with self._session() as session:
+            stmt = (
+                select(OrchestratorEmail)
+                .where(
+                    OrchestratorEmail.mail_decky_uuid == mail_decky_uuid,
+                    or_(
+                        (OrchestratorEmail.sender_email == sender_email)
+                        & (OrchestratorEmail.recipient_email == recipient_email),
+                        (OrchestratorEmail.sender_email == recipient_email)
+                        & (OrchestratorEmail.recipient_email == sender_email),
+                    ),
+                    OrchestratorEmail.success.is_(True),
+                )
+                .order_by(desc(OrchestratorEmail.ts))
+                .limit(limit)
+            )
+            result = await session.execute(stmt)
+            return [r.model_dump(mode="json") for r in result.scalars().all()]
+
+    async def prune_orchestrator_emails(self, per_decky_cap: int = 10000) -> int:
+        """Trim per-mail-decky rows to *per_decky_cap*, oldest-first."""
+        deleted = 0
+        async with self._session() as session:
+            decky_rows = await session.execute(
+                select(OrchestratorEmail.mail_decky_uuid).distinct()
+            )
+            for (mail_uuid,) in decky_rows.all():
+                keep = await session.execute(
+                    select(OrchestratorEmail.uuid)
+                    .where(OrchestratorEmail.mail_decky_uuid == mail_uuid)
+                    .order_by(desc(OrchestratorEmail.ts))
+                    .limit(per_decky_cap)
+                )
+                keep_uuids = [u for (u,) in keep.all()]
+                if not keep_uuids:
+                    continue
+                from sqlalchemy import delete as _delete
+                stmt = _delete(OrchestratorEmail).where(
+                    OrchestratorEmail.mail_decky_uuid == mail_uuid,
+                    OrchestratorEmail.uuid.notin_(keep_uuids),
+                )
+                res = await session.execute(stmt)
+                deleted += res.rowcount or 0
+            await session.commit()
+        return deleted

tests/orchestrator/emailgen/test_driver.py

@@ -0,0 +1,169 @@
+"""EmailDriver: stub the Ollama subprocess + docker exec; verify EML
+parse-and-repair and payload metadata."""
+from __future__ import annotations
+
+import pytest
+
+from decnet.orchestrator.drivers import email as email_driver
+from decnet.orchestrator.emailgen.personas import EmailPersona
+from decnet.orchestrator.emailgen.scheduler import EmailAction
+
+
+def _persona(name="John", email="john@corp.com"):
+    return EmailPersona(
+        name=name,
+        email=email,
+        role="COO",
+        tone="formal",
+        mannerisms=["uses 'Best regards'"],
+        language="en",
+    )
+
+
+def _action(is_reply=False):
+    return EmailAction(
+        mail_decky_uuid="d1",
+        mail_decky_name="mailhost",
+        mail_decky_services=("imap",),
+        sender=_persona(),
+        recipient=_persona(name="Sarah", email="sarah@corp.com"),
+        thread_id="thr1",
+        parent_message_id="<old@corp.com>" if is_reply else None,
+        references="" if not is_reply else "<old@corp.com>",
+        subject_hint="Re: budget" if is_reply else None,
+        parent_excerpt=None,
+        context_hint="Q3 budget" if not is_reply else "Re: budget",
+        is_reply=is_reply,
+    )
+
+
+def test_parse_subject_and_body_extracts_subject_line():
+    out = "Subject: Quick update\n\nHi Sarah,\nNumbers attached.\n"
+    subject, body = email_driver._parse_subject_and_body(out)
+    assert subject == "Quick update"
+    assert body.startswith("Hi Sarah")
+
+
+def test_parse_subject_strips_code_fences():
+    out = "```\nSubject: Quick update\n\nbody\n```\n"
+    subject, body = email_driver._parse_subject_and_body(out)
+    assert subject == "Quick update"
+    assert body == "body"
+
+
+def test_parse_subject_falls_back_when_missing():
+    out = "Just a body, no subject\n"
+    subject, body = email_driver._parse_subject_and_body(out)
+    assert subject == "Business Communication"
+    assert "body" in body.lower()
+
+
+def test_build_eml_includes_required_headers():
+    from datetime import datetime, timezone
+
+    eml = email_driver._build_eml(
+        sender_name="John",
+        sender_email="john@corp.com",
+        recipient_name="Sarah",
+        recipient_email="sarah@corp.com",
+        subject="Q3 budget",
+        body="Hi Sarah,\nNumbers attached.",
+        message_id="<m1@corp.com>",
+        in_reply_to=None,
+        references="",
+        ts=datetime(2026, 4, 26, 12, 0, tzinfo=timezone.utc),
+    ).decode("utf-8")
+    assert "From: John <john@corp.com>" in eml
+    assert "To: Sarah <sarah@corp.com>" in eml
+    assert "Subject: Q3 budget" in eml
+    assert "Message-ID: <m1@corp.com>" in eml
+    assert "MIME-Version: 1.0" in eml
+    assert "In-Reply-To" not in eml
+
+
+def test_build_eml_threads_carry_in_reply_to_and_references():
+    from datetime import datetime, timezone
+
+    eml = email_driver._build_eml(
+        sender_name="John",
+        sender_email="john@corp.com",
+        recipient_name="Sarah",
+        recipient_email="sarah@corp.com",
+        subject="Re: Q3",
+        body="Following up.",
+        message_id="<m2@corp.com>",
+        in_reply_to="<m1@corp.com>",
+        references="<m1@corp.com>",
+        ts=datetime(2026, 4, 26, 12, 0, tzinfo=timezone.utc),
+    ).decode("utf-8")
+    assert "In-Reply-To: <m1@corp.com>" in eml
+    assert "References: <m1@corp.com>" in eml
+
+
+def test_container_for_imap_takes_priority():
+    assert email_driver._container_for("mailhost", ["imap", "pop3"]) == "mailhost-imap"
+
+
+def test_container_for_pop3_only():
+    assert email_driver._container_for("mailhost", ["pop3"]) == "mailhost-pop3"
+
+
+@pytest.mark.asyncio
+async def test_driver_run_success_path(monkeypatch):
+    """Stub both subprocess calls (ollama + docker exec) as success."""
+    calls: list[list[str]] = []
+
+    async def fake_run_capture(argv, *, stdin_data=None, timeout=8.0):
+        calls.append(list(argv))
+        if argv[0] == "ollama":
+            return 0, "Subject: Q3 budget\n\nHi Sarah,\nNumbers attached.\n", ""
+        # docker exec
+        return 0, "", ""
+
+    monkeypatch.setattr(email_driver, "_run_capture", fake_run_capture)
+
+    drv = email_driver.EmailDriver(model="llama3.1", ollama_timeout=1.0)
+    result = await drv.run(_action())
+    assert result.success is True
+    assert result.payload["model"] == "llama3.1"
+    assert result.payload["subject"] == "Q3 budget"
+    assert result.payload["language"] == "en"
+    assert result.payload["mannerisms_used"]
+    assert result.payload["message_id"].startswith("<")
+    assert result.payload["eml_path"].endswith(".eml")
+    assert result.payload["container"] == "mailhost-imap"
+    # Two subprocess calls: ollama, then docker exec.
+    assert calls[0][0] == "ollama"
+    assert calls[1][0] == "docker"
+
+
+@pytest.mark.asyncio
+async def test_driver_run_ollama_failure_short_circuits(monkeypatch):
+    async def fake_run_capture(argv, *, stdin_data=None, timeout=8.0):
+        if argv[0] == "ollama":
+            return 1, "", "ollama: model not found"
+        return 0, "", ""
+
+    monkeypatch.setattr(email_driver, "_run_capture", fake_run_capture)
+
+    drv = email_driver.EmailDriver()
+    result = await drv.run(_action())
+    assert result.success is False
+    assert result.payload["stage"] == "ollama"
+    assert "model not found" in result.payload["stderr"]
+
+
+@pytest.mark.asyncio
+async def test_driver_run_delivery_failure(monkeypatch):
+    async def fake_run_capture(argv, *, stdin_data=None, timeout=8.0):
+        if argv[0] == "ollama":
+            return 0, "Subject: hi\n\nbody\n", ""
+        return 1, "", "no such container"
+
+    monkeypatch.setattr(email_driver, "_run_capture", fake_run_capture)
+
+    drv = email_driver.EmailDriver()
+    result = await drv.run(_action())
+    assert result.success is False
+    assert result.payload["stage"] == "delivery"
+    assert "no such container" in result.payload["stderr"]

tests/orchestrator/emailgen/test_events.py

@@ -0,0 +1,72 @@
+"""events.to_row / topic_for / event_type_for."""
+from __future__ import annotations
+
+from decnet.bus import topics as _topics
+from decnet.orchestrator.drivers.base import ActivityResult
+from decnet.orchestrator.emailgen import events
+from decnet.orchestrator.emailgen.personas import EmailPersona
+from decnet.orchestrator.emailgen.scheduler import EmailAction
+
+
+def _persona(email="john@corp.com"):
+    return EmailPersona(
+        name="John", email=email, role="COO", tone="formal",
+        mannerisms=[], language="en",
+    )
+
+
+def _action():
+    return EmailAction(
+        mail_decky_uuid="d1",
+        mail_decky_name="mailhost",
+        mail_decky_services=("imap",),
+        sender=_persona(),
+        recipient=_persona(email="sarah@corp.com"),
+        thread_id="thr1",
+        parent_message_id=None,
+        references="",
+        subject_hint=None,
+        parent_excerpt=None,
+        context_hint="Q3 budget",
+        is_reply=False,
+    )
+
+
+def test_to_row_pulls_message_id_subject_from_payload():
+    res = ActivityResult(
+        success=True,
+        payload={
+            "message_id": "<m1@corp.com>",
+            "subject": "Q3 budget",
+            "language": "en",
+            "eml_path": "/var/spool/decnet-emails/thr1/m1.eml",
+            "model": "llama3.1",
+        },
+    )
+    row = events.to_row(_action(), res)
+    assert row["mail_decky_uuid"] == "d1"
+    assert row["thread_id"] == "thr1"
+    assert row["message_id"] == "<m1@corp.com>"
+    assert row["subject"] == "Q3 budget"
+    assert row["sender_email"] == "john@corp.com"
+    assert row["recipient_email"] == "sarah@corp.com"
+    assert row["language"] == "en"
+    assert row["eml_path"].endswith(".eml")
+    assert row["success"] is True
+    assert row["payload"]["model"] == "llama3.1"
+
+
+def test_to_row_falls_back_to_persona_language():
+    res = ActivityResult(success=True, payload={})
+    row = events.to_row(_action(), res)
+    assert row["language"] == "en"
+    assert row["message_id"] == ""
+
+
+def test_topic_for_uses_orchestrator_email_root():
+    topic = events.topic_for(_action())
+    assert topic == f"orchestrator.{_topics.ORCHESTRATOR_EMAIL}.d1"
+
+
+def test_event_type_for_returns_email_constant():
+    assert events.event_type_for(_action()) == _topics.ORCHESTRATOR_EMAIL

tests/orchestrator/emailgen/test_personas.py

@@ -0,0 +1,101 @@
+"""Persona schema parsing + active-hours window tests."""
+from __future__ import annotations
+
+import json
+
+from decnet.orchestrator.emailgen.personas import (
+    EmailPersona,
+    in_active_hours,
+    parse_personas,
+)
+
+
+def _persona(**over) -> dict:
+    base = {
+        "name": "John Smith",
+        "email": "john@corp.com",
+        "role": "COO",
+        "tone": "formal",
+        "mannerisms": ["uses 'Best regards'"],
+    }
+    base.update(over)
+    return base
+
+
+def test_parse_empty_inputs():
+    assert parse_personas(None) == []
+    assert parse_personas("") == []
+    assert parse_personas([]) == []
+
+
+def test_parse_invalid_json_returns_empty_no_raise():
+    assert parse_personas("{not json") == []
+
+
+def test_parse_invalid_top_level_shape_returns_empty():
+    assert parse_personas('{"not": "a list"}') == []
+
+
+def test_parse_drops_invalid_entry_keeps_valid():
+    raw = json.dumps([
+        _persona(),
+        {"name": "broken", "email": "not-an-email"},
+        _persona(name="Sarah", email="sarah@corp.com"),
+    ])
+    parsed = parse_personas(raw)
+    assert len(parsed) == 2
+    assert {p.name for p in parsed} == {"John Smith", "Sarah"}
+
+
+def test_parse_resolves_language_default_when_unset():
+    raw = json.dumps([_persona()])
+    parsed = parse_personas(raw, language_default="es")
+    assert parsed[0].language == "es"
+
+
+def test_parse_persona_language_overrides_default():
+    raw = json.dumps([_persona(language="pt")])
+    parsed = parse_personas(raw, language_default="es")
+    assert parsed[0].language == "pt"
+
+
+def test_parse_accepts_python_list_directly():
+    parsed = parse_personas([_persona()])
+    assert len(parsed) == 1
+
+
+def test_uses_llms_heavily_default_false():
+    parsed = parse_personas([_persona()])
+    assert parsed[0].uses_llms_heavily is False
+
+
+def test_uses_llms_heavily_can_be_set():
+    parsed = parse_personas([_persona(uses_llms_heavily=True)])
+    assert parsed[0].uses_llms_heavily is True
+
+
+def test_active_hours_normal_window():
+    p = EmailPersona(**_persona(active_hours="09:00-18:00"))
+    assert in_active_hours(p, 12) is True
+    assert in_active_hours(p, 8) is False
+    assert in_active_hours(p, 18) is False
+    assert in_active_hours(p, 9) is True
+
+
+def test_active_hours_wraparound_window():
+    p = EmailPersona(**_persona(active_hours="22:00-06:00"))
+    assert in_active_hours(p, 23) is True
+    assert in_active_hours(p, 0) is True
+    assert in_active_hours(p, 5) is True
+    assert in_active_hours(p, 7) is False
+
+
+def test_active_hours_malformed_treats_as_always_on():
+    p = EmailPersona(**_persona(active_hours="garbage"))
+    assert in_active_hours(p, 0) is True
+    assert in_active_hours(p, 23) is True
+
+
+def test_active_hours_equal_window_treated_as_always_on():
+    p = EmailPersona(**_persona(active_hours="10:00-10:00"))
+    assert in_active_hours(p, 5) is True

tests/orchestrator/emailgen/test_prompt.py

@@ -0,0 +1,152 @@
+"""Prompt builder behaviour: language constraint, em-dash suppression,
+deterministic mannerism injection."""
+from __future__ import annotations
+
+import random
+
+from decnet.orchestrator.emailgen.personas import EmailPersona
+from decnet.orchestrator.emailgen.prompt import (
+    PromptInputs,
+    build,
+    select_mannerisms,
+)
+
+
+def _persona(**over) -> EmailPersona:
+    base = dict(
+        name="John Smith",
+        email="john@corp.com",
+        role="COO",
+        tone="formal",
+        mannerisms=[
+            "opens with 'I hope this finds you well'",
+            "uses 'Best regards' exclusively",
+            "references policy by number",
+            "ccs legal",
+        ],
+        language="en",
+    )
+    base.update(over)
+    return EmailPersona(**base)
+
+
+class _SeededRng:
+    """Adapter so prompt code thinks it has a SystemRandom."""
+
+    def __init__(self, seed: int):
+        self._r = random.Random(seed)
+
+    def shuffle(self, seq):
+        self._r.shuffle(seq)
+
+    def random(self):
+        return self._r.random()
+
+    def choice(self, seq):
+        return self._r.choice(seq)
+
+
+def test_select_mannerisms_returns_subset_of_pool():
+    persona = _persona()
+    picks = select_mannerisms(persona, rng=_SeededRng(0), n=2)
+    assert len(picks) == 2
+    assert all(m in persona.mannerisms for m in picks)
+
+
+def test_select_mannerisms_deterministic_under_same_seed():
+    persona = _persona()
+    a = select_mannerisms(persona, rng=_SeededRng(42), n=2)
+    b = select_mannerisms(persona, rng=_SeededRng(42), n=2)
+    assert a == b
+
+
+def test_select_mannerisms_returns_all_when_pool_smaller_than_n():
+    persona = _persona(mannerisms=["a"])
+    picks = select_mannerisms(persona, rng=_SeededRng(0), n=2)
+    assert picks == ["a"]
+
+
+def test_select_mannerisms_empty_pool():
+    persona = _persona(mannerisms=[])
+    assert select_mannerisms(persona) == []
+
+
+def test_build_includes_language_constraint_english():
+    sender = _persona(language="en")
+    recip = _persona(name="Sarah", email="sarah@corp.com", role="PM")
+    prompt, _ = build(
+        PromptInputs(sender=sender, recipient=recip, context_hint="budget"),
+        rng=_SeededRng(0),
+    )
+    assert "in English" in prompt
+
+
+def test_build_includes_language_constraint_spanish():
+    sender = _persona(language="es")
+    recip = _persona(name="Sarah", email="sarah@corp.com", role="PM")
+    prompt, _ = build(
+        PromptInputs(sender=sender, recipient=recip, context_hint="budget"),
+        rng=_SeededRng(0),
+    )
+    assert "in Spanish" in prompt
+
+
+def test_build_em_dash_suppression_default():
+    sender = _persona()
+    recip = _persona(name="Sarah", email="sarah@corp.com", role="PM")
+    prompt, _ = build(
+        PromptInputs(sender=sender, recipient=recip, context_hint="budget"),
+        rng=_SeededRng(0),
+    )
+    assert "Do NOT use em-dashes" in prompt
+
+
+def test_build_em_dash_lifted_for_llm_heavy_persona():
+    sender = _persona(uses_llms_heavily=True)
+    recip = _persona(name="Sarah", email="sarah@corp.com", role="PM")
+    prompt, _ = build(
+        PromptInputs(sender=sender, recipient=recip, context_hint="budget"),
+        rng=_SeededRng(0),
+    )
+    assert "Do NOT use em-dashes" not in prompt
+    assert "fine" in prompt.lower()
+
+
+def test_build_reply_thread_block_prefixes_re():
+    sender = _persona()
+    recip = _persona(name="Sarah", email="sarah@corp.com", role="PM")
+    prompt, _ = build(
+        PromptInputs(
+            sender=sender,
+            recipient=recip,
+            context_hint="budget",
+            parent_subject="Re: Q3 budget",
+            parent_excerpt="Numbers attached.",
+        ),
+        rng=_SeededRng(0),
+    )
+    assert "REPLY in an ongoing thread" in prompt
+    assert "Re: Q3 budget" in prompt
+    assert "Numbers attached" in prompt
+    assert "prefixed with 'Re: '" in prompt
+
+
+def test_build_returns_mannerisms_used_metadata():
+    sender = _persona()
+    recip = _persona(name="Sarah", email="sarah@corp.com", role="PM")
+    _, used = build(
+        PromptInputs(sender=sender, recipient=recip, context_hint="budget"),
+        rng=_SeededRng(7),
+    )
+    assert used
+    assert all(m in sender.mannerisms for m in used)
+
+
+def test_build_uses_explicit_signature_when_provided():
+    sender = _persona(signature="-- John\\nCOO")
+    recip = _persona(name="Sarah", email="sarah@corp.com", role="PM")
+    prompt, _ = build(
+        PromptInputs(sender=sender, recipient=recip, context_hint="budget"),
+        rng=_SeededRng(0),
+    )
+    assert "Use this exact signature block" in prompt

tests/orchestrator/emailgen/test_repo.py

@@ -0,0 +1,129 @@
+"""record / list / count / prune orchestrator_emails on a real SQLite repo."""
+from __future__ import annotations
+
+import json
+from datetime import datetime, timedelta, timezone
+
+import pytest
+import pytest_asyncio
+
+from decnet.web.db.sqlite.repository import SQLiteRepository
+
+
+@pytest_asyncio.fixture
+async def repo(tmp_path):
+    r = SQLiteRepository(db_path=str(tmp_path / "decnet.db"))
+    await r.initialize()
+    yield r
+    await r.engine.dispose()
+
+
+def _row(
+    mail="d1",
+    thread="thr1",
+    msg="<m1@x>",
+    sender="john@corp.com",
+    recipient="sarah@corp.com",
+    subject="Q3 budget",
+    success=True,
+    in_reply_to=None,
+    ts=None,
+):
+    return {
+        "ts": ts or datetime.now(timezone.utc),
+        "mail_decky_uuid": mail,
+        "thread_id": thread,
+        "message_id": msg,
+        "in_reply_to": in_reply_to,
+        "sender_email": sender,
+        "recipient_email": recipient,
+        "subject": subject,
+        "language": "en",
+        "eml_path": f"/var/spool/decnet-emails/{thread}/{msg}.eml",
+        "success": success,
+        "payload": {"model": "llama3.1"},
+    }
+
+
+@pytest.mark.asyncio
+async def test_record_returns_uuid_and_serialises_payload(repo):
+    uuid = await repo.record_orchestrator_email(_row())
+    assert isinstance(uuid, str) and len(uuid) == 36
+    rows = await repo.list_orchestrator_emails()
+    assert len(rows) == 1
+    # payload is stored as JSON text, list endpoint hands it back as the
+    # raw column value — we just verify it round-trips intact.
+    assert json.loads(rows[0]["payload"])["model"] == "llama3.1"
+
+
+@pytest.mark.asyncio
+async def test_list_filters_by_thread_and_mail_decky(repo):
+    await repo.record_orchestrator_email(_row(thread="t1", msg="<a@x>"))
+    await repo.record_orchestrator_email(_row(thread="t2", msg="<b@x>"))
+    await repo.record_orchestrator_email(_row(mail="d2", msg="<c@x>"))
+
+    by_thread = await repo.list_orchestrator_emails(thread_id="t1")
+    assert {r["message_id"] for r in by_thread} == {"<a@x>"}
+
+    by_mail = await repo.list_orchestrator_emails(mail_decky_uuid="d1")
+    assert len(by_mail) == 2
+
+    everything = await repo.list_orchestrator_emails()
+    assert len(everything) == 3
+
+
+@pytest.mark.asyncio
+async def test_count_orchestrator_emails(repo):
+    for i in range(3):
+        await repo.record_orchestrator_email(_row(msg=f"<m{i}@x>"))
+    assert await repo.count_orchestrator_emails() == 3
+    assert await repo.count_orchestrator_emails(mail_decky_uuid="d1") == 3
+    assert await repo.count_orchestrator_emails(mail_decky_uuid="other") == 0
+
+
+@pytest.mark.asyncio
+async def test_thread_lookup_only_returns_pair_threads(repo):
+    await repo.record_orchestrator_email(
+        _row(sender="john@corp.com", recipient="sarah@corp.com", msg="<a@x>")
+    )
+    # Reverse direction (Sarah → John) should still match the same pair.
+    await repo.record_orchestrator_email(
+        _row(sender="sarah@corp.com", recipient="john@corp.com", msg="<b@x>")
+    )
+    # Unrelated pair must not match.
+    await repo.record_orchestrator_email(
+        _row(sender="mike@corp.com", recipient="sarah@corp.com", msg="<c@x>")
+    )
+    threads = await repo.list_orchestrator_email_threads(
+        "d1", "john@corp.com", "sarah@corp.com",
+    )
+    assert {t["message_id"] for t in threads} == {"<a@x>", "<b@x>"}
+
+
+@pytest.mark.asyncio
+async def test_thread_lookup_excludes_failed_rows(repo):
+    await repo.record_orchestrator_email(_row(msg="<ok@x>", success=True))
+    await repo.record_orchestrator_email(_row(msg="<bad@x>", success=False))
+    threads = await repo.list_orchestrator_email_threads(
+        "d1", "john@corp.com", "sarah@corp.com",
+    )
+    assert {t["message_id"] for t in threads} == {"<ok@x>"}
+
+
+@pytest.mark.asyncio
+async def test_prune_caps_per_decky(repo):
+    # Insert 5 rows on d1 with strictly-increasing timestamps so the
+    # prune's "newest-first keep, drop the rest" deterministically picks
+    # the older two.
+    base = datetime.now(timezone.utc) - timedelta(hours=10)
+    for i in range(5):
+        await repo.record_orchestrator_email(
+            _row(msg=f"<m{i}@x>", ts=base + timedelta(minutes=i))
+        )
+    # Cap at 3 — expect 2 deleted.
+    deleted = await repo.prune_orchestrator_emails(per_decky_cap=3)
+    assert deleted == 2
+    remaining = await repo.list_orchestrator_emails()
+    assert len(remaining) == 3
+    # The three newest survived.
+    assert {r["message_id"] for r in remaining} == {"<m2@x>", "<m3@x>", "<m4@x>"}

tests/orchestrator/emailgen/test_scheduler.py

@@ -0,0 +1,161 @@
+"""Scheduler.pick() — async, takes a repo-shaped object."""
+from __future__ import annotations
+
+import json
+from datetime import datetime
+from typing import Any
+
+import pytest
+
+from decnet.orchestrator.emailgen import scheduler
+
+
+_PERSONAS_TWO = [
+    {
+        "name": "John Smith",
+        "email": "john@corp.com",
+        "role": "COO",
+        "tone": "formal",
+        "mannerisms": ["uses 'Best regards'"],
+    },
+    {
+        "name": "Sarah Johnson",
+        "email": "sarah@corp.com",
+        "role": "PM",
+        "tone": "direct",
+        "mannerisms": ["uses bullets"],
+    },
+]
+
+
+class _FakeRepo:
+    """Minimal repo stub matching the methods scheduler.pick() uses."""
+
+    def __init__(
+        self,
+        *,
+        deckies: list[dict[str, Any]] | None = None,
+        topologies: dict[str, dict[str, Any]] | None = None,
+        threads: list[dict[str, Any]] | None = None,
+    ):
+        self.deckies = deckies or []
+        self.topologies = topologies or {}
+        self.threads = threads or []
+        self.thread_calls = 0
+
+    async def list_running_topology_deckies(self):
+        return self.deckies
+
+    async def get_topology(self, topology_id: str):
+        return self.topologies.get(topology_id)
+
+    async def list_orchestrator_email_threads(self, *args, **kwargs):
+        self.thread_calls += 1
+        return list(self.threads)
+
+
+def _decky(uuid="d1", name="mailhost", services=("imap",), topology_id="t1"):
+    return {
+        "uuid": uuid,
+        "name": name,
+        "services": list(services),
+        "topology_id": topology_id,
+    }
+
+
+def _topology(personas=_PERSONAS_TWO, language_default="en"):
+    return {
+        "id": "t1",
+        "email_personas": json.dumps(personas),
+        "language_default": language_default,
+    }
+
+
+@pytest.mark.asyncio
+async def test_pick_no_mail_decky_returns_none():
+    repo = _FakeRepo(deckies=[_decky(services=("ssh",))])
+    assert await scheduler.pick(repo) is None
+
+
+@pytest.mark.asyncio
+async def test_pick_unknown_topology_returns_none():
+    repo = _FakeRepo(deckies=[_decky()])
+    # No topology row for "t1" — scheduler should bail.
+    assert await scheduler.pick(repo) is None
+
+
+@pytest.mark.asyncio
+async def test_pick_topology_with_one_persona_returns_none():
+    repo = _FakeRepo(
+        deckies=[_decky()],
+        topologies={"t1": _topology(personas=_PERSONAS_TWO[:1])},
+    )
+    assert await scheduler.pick(repo) is None
+
+
+@pytest.mark.asyncio
+async def test_pick_returns_action_for_valid_setup():
+    repo = _FakeRepo(
+        deckies=[_decky()],
+        topologies={"t1": _topology()},
+    )
+    action = await scheduler.pick(repo, now=datetime(2026, 4, 26, 12, 0, 0))
+    assert action is not None
+    assert action.mail_decky_uuid == "d1"
+    assert action.sender.email != action.recipient.email
+    assert action.thread_id  # populated for both new and reply branches
+
+
+@pytest.mark.asyncio
+async def test_pick_active_hours_filter_kicks_in_at_midnight():
+    repo = _FakeRepo(
+        deckies=[_decky()],
+        topologies={"t1": _topology()},
+    )
+    # Default active_hours is 09:00-18:00; midnight => everyone out of office.
+    action = await scheduler.pick(repo, now=datetime(2026, 4, 26, 3, 0, 0))
+    assert action is None
+
+
+@pytest.mark.asyncio
+async def test_pick_uses_pop3_decky_too():
+    repo = _FakeRepo(
+        deckies=[_decky(services=("pop3",))],
+        topologies={"t1": _topology()},
+    )
+    action = await scheduler.pick(repo, now=datetime(2026, 4, 26, 12, 0, 0))
+    assert action is not None
+
+
+@pytest.mark.asyncio
+async def test_pick_reply_chain_sets_in_reply_to():
+    threads = [{
+        "thread_id": "thr1",
+        "message_id": "<old@corp.com>",
+        "subject": "Q3 budget",
+    }]
+    repo = _FakeRepo(
+        deckies=[_decky()],
+        topologies={"t1": _topology()},
+        threads=threads,
+    )
+
+    # Force the "reply" branch by stubbing the RNG: random() < 0.6 is True.
+    class _Rng:
+        def __init__(self):
+            self.calls = 0
+
+        def choice(self, seq):
+            return seq[0]
+
+        def random(self):
+            return 0.0    # always reply
+
+    action = await scheduler.pick(
+        repo, rand=_Rng(), now=datetime(2026, 4, 26, 12, 0, 0),
+    )
+    assert action is not None
+    assert action.is_reply is True
+    assert action.parent_message_id == "<old@corp.com>"
+    assert action.thread_id == "thr1"
+    assert action.subject_hint == "Re: Q3 budget"

tests/orchestrator/emailgen/test_threads.py

@@ -0,0 +1,61 @@
+"""Thread-chain helpers."""
+from __future__ import annotations
+
+from decnet.orchestrator.emailgen.threads import (
+    ThreadChain,
+    new_message_id,
+    new_thread_id,
+    references_for_reply,
+    reply_subject,
+)
+
+
+def test_new_thread_id_is_uuid_string():
+    tid = new_thread_id()
+    assert len(tid) == 36
+    assert tid.count("-") == 4
+
+
+def test_new_message_id_format_with_domain():
+    mid = new_message_id("example.com")
+    assert mid.startswith("<") and mid.endswith(">")
+    assert "@example.com" in mid
+
+
+def test_new_message_id_handles_blank_domain():
+    mid = new_message_id("   ")
+    assert "@localhost" in mid
+
+
+def test_reply_subject_prepends_re():
+    assert reply_subject("Q3 budget") == "Re: Q3 budget"
+
+
+def test_reply_subject_collapses_existing_re():
+    assert reply_subject("Re: Re: Q3 budget") == "Re: Q3 budget"
+    assert reply_subject("RE: Q3 budget") == "Re: Q3 budget"
+
+
+def test_references_for_reply_root_is_empty():
+    assert references_for_reply(None) == ""
+
+
+def test_references_for_reply_appends_parent():
+    chain = ThreadChain(
+        thread_id="t1",
+        parent_message_id="<m2@x>",
+        references=("<m1@x>",),
+        parent_subject="Re: budget",
+    )
+    refs = references_for_reply(chain)
+    assert refs == "<m1@x> <m2@x>"
+
+
+def test_references_empty_chain_starts_with_parent_only():
+    chain = ThreadChain(
+        thread_id="t1",
+        parent_message_id="<m1@x>",
+        references=(),
+        parent_subject="budget",
+    )
+    assert references_for_reply(chain) == "<m1@x>"

tests/orchestrator/emailgen/test_worker_integration.py

@@ -0,0 +1,136 @@
+"""End-to-end-ish: one emailgen tick against a real SQLite repo + FakeBus,
+with the Ollama + docker-exec subprocess stubbed."""
+from __future__ import annotations
+
+import json
+
+import pytest
+import pytest_asyncio
+
+from decnet.bus.fake import FakeBus
+from decnet.orchestrator.drivers import email as email_driver
+from decnet.orchestrator.emailgen import worker as eg_worker
+from decnet.orchestrator.emailgen.scheduler import EmailAction  # noqa: F401
+from decnet.web.db.models import Topology, TopologyDecky
+from decnet.web.db.sqlite.repository import SQLiteRepository
+
+
+_PERSONAS = [
+    {
+        "name": "John Smith",
+        "email": "john@corp.com",
+        "role": "COO",
+        "tone": "formal",
+        "mannerisms": ["uses 'Best regards'"],
+        "active_hours": "00:00-00:00",  # always-on so test is hour-independent
+    },
+    {
+        "name": "Sarah Johnson",
+        "email": "sarah@corp.com",
+        "role": "PM",
+        "tone": "direct",
+        "mannerisms": ["uses bullets"],
+        "active_hours": "00:00-00:00",
+    },
+]
+
+
+@pytest_asyncio.fixture
+async def repo(tmp_path):
+    r = SQLiteRepository(db_path=str(tmp_path / "decnet.db"))
+    await r.initialize()
+    yield r
+    await r.engine.dispose()
+
+
+@pytest_asyncio.fixture
+async def fake_bus():
+    bus = FakeBus()
+    await bus.connect()
+    try:
+        yield bus
+    finally:
+        await bus.close()
+
+
+async def _seed_mail_topology(repo: SQLiteRepository) -> str:
+    async with repo._session() as session:
+        topo = Topology(
+            name="t-mail",
+            config_snapshot="{}",
+            status="active",
+            email_personas=json.dumps(_PERSONAS),
+            language_default="en",
+        )
+        session.add(topo)
+        await session.commit()
+        await session.refresh(topo)
+        decky = TopologyDecky(
+            topology_id=topo.id,
+            name="mailhost",
+            services=json.dumps(["imap"]),
+            ip="10.0.0.10",
+            state="running",
+        )
+        session.add(decky)
+        await session.commit()
+        await session.refresh(decky)
+        return decky.uuid
+
+
+@pytest.mark.asyncio
+async def test_one_tick_records_and_publishes(repo, fake_bus, monkeypatch):
+    decky_uuid = await _seed_mail_topology(repo)
+
+    async def fake_run_capture(argv, *, stdin_data=None, timeout=8.0):
+        if argv[0] == "ollama":
+            return 0, "Subject: Hi\n\nBody here.\n", ""
+        return 0, "", ""
+
+    monkeypatch.setattr(email_driver, "_run_capture", fake_run_capture)
+
+    received: list = []
+
+    async def collect():
+        async with fake_bus.subscribe(f"orchestrator.email.{decky_uuid}") as sub:
+            async for ev in sub:
+                received.append(ev)
+                return
+
+    import asyncio
+    collector = asyncio.create_task(collect())
+    await asyncio.sleep(0)
+
+    driver = email_driver.EmailDriver()
+    await eg_worker._one_tick(repo, driver, fake_bus)
+    await asyncio.wait_for(collector, timeout=2.0)
+
+    rows = await repo.list_orchestrator_emails()
+    assert len(rows) == 1
+    row = rows[0]
+    assert row["success"] is True
+    assert row["mail_decky_uuid"] == decky_uuid
+    assert row["subject"] == "Hi"
+    assert row["language"] == "en"
+
+    assert len(received) == 1
+    assert received[0].topic == f"orchestrator.email.{decky_uuid}"
+    assert received[0].payload["kind"] == "email"
+    assert received[0].payload["success"] is True
+
+
+@pytest.mark.asyncio
+async def test_one_tick_noop_when_no_mail_decky(repo, fake_bus, monkeypatch):
+    called = False
+
+    async def fake_run_capture(argv, *, stdin_data=None, timeout=8.0):
+        nonlocal called
+        called = True
+        return 0, "Subject: x\n\nb\n", ""
+
+    monkeypatch.setattr(email_driver, "_run_capture", fake_run_capture)
+
+    driver = email_driver.EmailDriver()
+    await eg_worker._one_tick(repo, driver, fake_bus)
+    assert called is False
+    assert await repo.list_orchestrator_emails() == []