analysis_claude_code/s16_autonomous_agents/code.py

#!/usr/bin/env python3
"""
s16: Autonomous Agents — idle teammates discover and claim ready tasks.

Run:  python s16_autonomous_agents/code.py
Need: pip install anthropic python-dotenv + .env with ANTHROPIC_API_KEY

Changes from s15:
  - scan_unclaimed_tasks finds pending, unowned, unblocked tasks
  - Idle teammates periodically scan the shared task board
  - claim_next_task atomically assigns one ready task to a teammate
  - Teammates can list, claim, and complete tasks

ASCII flow:
  WORK → result → IDLE → scan board → claim ready task → WORK
                       └→ inbox or shutdown event
"""

import os, subprocess, json, time, random, threading, queue, re
from pathlib import Path
from datetime import datetime
from dataclasses import dataclass, asdict, field

try:
    import readline
    readline.parse_and_bind('set bind-tty-special-chars off')
except ImportError:
    pass

from anthropic import Anthropic
from dotenv import load_dotenv

load_dotenv(override=True)
if os.getenv("ANTHROPIC_BASE_URL"):
    os.environ.pop("ANTHROPIC_AUTH_TOKEN", None)

WORKDIR = Path.cwd()
MEMORY_DIR = WORKDIR / ".memory"
MEMORY_INDEX = MEMORY_DIR / "MEMORY.md"
client = Anthropic(base_url=os.getenv("ANTHROPIC_BASE_URL"))
MODEL = os.environ["MODEL_ID"]

# ── Task System (from s12, synced) ──

TASKS_DIR = WORKDIR / ".tasks"
TASKS_DIR.mkdir(exist_ok=True)
task_lock = threading.RLock()


@dataclass
class Task:
    id: str
    subject: str
    description: str
    status: str          # pending | in_progress | completed
    owner: str | None
    blockedBy: list[str]


def _task_path(task_id: str) -> Path:
    return TASKS_DIR / f"{task_id}.json"


def create_task(subject: str, description: str = "",
                blockedBy: list[str] | None = None) -> Task:
    task = Task(
        id=f"task_{int(time.time())}_{random.randint(0, 9999):04d}",
        subject=subject, description=description,
        status="pending", owner=None,
        blockedBy=blockedBy or [],
    )
    save_task(task)
    return task


def save_task(task: Task):
    _task_path(task.id).write_text(json.dumps(asdict(task), indent=2))


def load_task(task_id: str) -> Task:
    return Task(**json.loads(_task_path(task_id).read_text()))


def list_tasks() -> list[Task]:
    return [Task(**json.loads(p.read_text()))
            for p in sorted(TASKS_DIR.glob("task_*.json"))]


def get_task(task_id: str) -> str:
    """Return full task details as JSON."""
    task = load_task(task_id)
    return json.dumps(asdict(task), indent=2)


def can_start(task_id: str) -> bool:
    """Check if all blockedBy dependencies are completed.
    Missing dependencies are treated as blocked."""
    task = load_task(task_id)
    for dep_id in task.blockedBy:
        if not _task_path(dep_id).exists():
            return False
        if load_task(dep_id).status != "completed":
            return False
    return True


def claim_task(task_id: str, owner: str = "agent") -> str:
    with task_lock:
        task = load_task(task_id)
        if task.status != "pending":
            return f"Task {task_id} is {task.status}, cannot claim"
        if task.owner:
            return f"Task {task_id} is already owned by {task.owner}"
        if not can_start(task_id):
            deps = [d for d in task.blockedBy
                    if (not _task_path(d).exists()
                        or load_task(d).status != "completed")]
            return f"Blocked by: {deps}"
        task.owner = owner
        task.status = "in_progress"
        save_task(task)
    print(f"  \033[36m[claim] {task.subject} → in_progress (owner: {owner})\033[0m")
    return f"Claimed {task.id} ({task.subject})"


def complete_task(task_id: str) -> str:
    task = load_task(task_id)
    if task.status != "in_progress":
        return f"Task {task_id} is {task.status}, cannot complete"
    task.status = "completed"
    save_task(task)
    unblocked = [t.subject for t in list_tasks()
                 if t.status == "pending" and t.blockedBy and can_start(t.id)]
    print(f"  \033[32m[complete] {task.subject} ✓\033[0m")
    msg = f"Completed {task.id} ({task.subject})"
    if unblocked:
        msg += f"\nUnblocked: {', '.join(unblocked)}"
        print(f"  \033[33m[unblocked] {', '.join(unblocked)}\033[0m")
    return msg


# ── Prompt Assembly (from s10, synced) ──

PROMPT_SECTIONS = {
    "identity": "You are a coding agent. Act, don't explain.",
    "tools": "Available tools: bash, read_file, write_file, "
             "get_task, create_task, list_tasks, claim_task, complete_task, "
             "schedule_cron, list_crons, cancel_cron, "
             "spawn_teammate, send_message, request_shutdown, "
             "request_plan, review_plan.",
    "teams": (
        "When parallel work would help, first propose a small team with clear "
        "responsibilities and wait for the user's confirmation. Do not call "
        "spawn_teammate before the user confirms. After confirmation, delegate "
        "independent work, react to team events delivered by the runtime, and "
        "shut teammates down when coordination is complete."
    ),
    "workspace": f"Working directory: {WORKDIR}",
    "memory": "Relevant memories are injected below when available.",
}


def assemble_system_prompt(context: dict) -> str:
    sections = [PROMPT_SECTIONS["identity"],
                PROMPT_SECTIONS["tools"],
                PROMPT_SECTIONS["teams"],
                PROMPT_SECTIONS["workspace"]]
    memories = context.get("memories", "")
    if memories:
        sections.append(f"Relevant memories:\n{memories}")
    return "\n\n".join(sections)


_last_context_key, _last_prompt = None, None


def get_system_prompt(context: dict) -> str:
    global _last_context_key, _last_prompt
    key = json.dumps(context, sort_keys=True, ensure_ascii=False, default=str)
    if key == _last_context_key and _last_prompt:
        return _last_prompt
    _last_context_key = key
    _last_prompt = assemble_system_prompt(context)
    return _last_prompt


# ── Tools ──

def safe_path(p: str) -> Path:
    path = (WORKDIR / p).resolve()
    if not path.is_relative_to(WORKDIR):
        raise ValueError(f"Path escapes workspace: {p}")
    return path


def run_bash(command: str, run_in_background: bool = False) -> str:
    # run_in_background is handled by agent_loop dispatch, not here
    try:
        r = subprocess.run(command, shell=True, cwd=WORKDIR,
                           capture_output=True, text=True, timeout=120)
        out = (r.stdout + r.stderr).strip()
        return out[:50000] if out else "(no output)"
    except subprocess.TimeoutExpired:
        return "Error: Timeout (120s)"


def run_read(path: str, limit: int | None = None) -> str:
    try:
        lines = safe_path(path).read_text().splitlines()
        if limit and limit < len(lines):
            lines = lines[:limit] + [f"... ({len(lines) - limit} more lines)"]
        return "\n".join(lines)
    except Exception as e:
        return f"Error: {e}"


def run_write(path: str, content: str) -> str:
    try:
        fp = safe_path(path)
        fp.parent.mkdir(parents=True, exist_ok=True)
        fp.write_text(content)
        return f"Wrote {len(content)} bytes to {path}"
    except Exception as e:
        return f"Error: {e}"


# Task tools

def run_create_task(subject: str, description: str = "",
                    blockedBy: list[str] | None = None) -> str:
    task = create_task(subject, description, blockedBy)
    deps = f" (blockedBy: {', '.join(blockedBy)})" if blockedBy else ""
    print(f"  \033[34m[create] {task.subject}{deps}\033[0m")
    return f"Created {task.id}: {task.subject}{deps}"


def run_list_tasks() -> str:
    tasks = list_tasks()
    if not tasks:
        return "No tasks. Use create_task to add some."
    lines = []
    for t in tasks:
        icon = {"pending": "○", "in_progress": "●",
                "completed": "✓"}.get(t.status, "?")
        deps = f" (blockedBy: {', '.join(t.blockedBy)})" if t.blockedBy else ""
        owner = f" [{t.owner}]" if t.owner else ""
        lines.append(f"  {icon} {t.id}: {t.subject} "
                     f"[{t.status}]{owner}{deps}")
    return "\n".join(lines)


def run_get_task(task_id: str) -> str:
    try:
        return get_task(task_id)
    except FileNotFoundError:
        return f"Error: Task {task_id} not found"


def run_claim_task(task_id: str) -> str:
    return claim_task(task_id, owner="agent")


def run_complete_task(task_id: str) -> str:
    return complete_task(task_id)


# ── Background Tasks (from s13, synced) ──

_bg_counter = 0
background_tasks: dict[str, dict] = {}
background_results: dict[str, str] = {}
background_lock = threading.Lock()


def is_slow_operation(tool_name: str, tool_input: dict) -> bool:
    """Fallback heuristic: commands likely to take > 30s."""
    if tool_name != "bash":
        return False
    cmd = tool_input.get("command", "").lower()
    slow_keywords = ["install", "build", "test", "deploy", "compile",
                     "docker build", "pip install", "npm install",
                     "cargo build", "pytest", "make"]
    return any(kw in cmd for kw in slow_keywords)


def should_run_background(tool_name: str, tool_input: dict) -> bool:
    """Model explicit request takes priority; fallback to heuristic."""
    if tool_input.get("run_in_background"):
        return True
    return is_slow_operation(tool_name, tool_input)


def execute_tool(block) -> str:
    """Execute a tool call block, return output."""
    handler = {
        "bash": run_bash, "read_file": run_read, "write_file": run_write,
        "create_task": run_create_task, "list_tasks": run_list_tasks,
        "get_task": run_get_task, "claim_task": run_claim_task,
        "complete_task": run_complete_task,
        "schedule_cron": run_schedule_cron, "list_crons": run_list_crons,
        "cancel_cron": run_cancel_cron,
        "spawn_teammate": run_spawn_teammate,
        "send_message": run_send_message,
        "request_shutdown": run_request_shutdown,
        "request_plan": run_request_plan,
        "review_plan": run_review_plan,
    }.get(block.name)
    if handler:
        return handler(**block.input)
    return f"Unknown tool: {block.name}"


def start_background_task(block) -> str:
    """Run tool in a daemon thread. Returns background task ID."""
    global _bg_counter
    _bg_counter += 1
    bg_id = f"bg_{_bg_counter:04d}"
    cmd = block.input.get("command", block.name)

    def worker():
        result = execute_tool(block)
        with background_lock:
            background_tasks[bg_id]["status"] = "completed"
            background_results[bg_id] = result

    with background_lock:
        background_tasks[bg_id] = {
            "tool_use_id": block.id,
            "command": cmd,
            "status": "running",
        }
    threading.Thread(target=worker, daemon=True).start()
    print(f"  \033[33m[background] dispatched {bg_id}: {cmd[:40]}\033[0m")
    return bg_id


def collect_background_results() -> list[str]:
    """Collect completed background results as task_notification messages."""
    with background_lock:
        ready_ids = [bid for bid, task in background_tasks.items()
                     if task["status"] == "completed"]
    notifications = []
    for bg_id in ready_ids:
        with background_lock:
            task = background_tasks.pop(bg_id)
            output = background_results.pop(bg_id, "")
        summary = output[:200] if len(output) > 200 else output
        notifications.append(
            f"<task_notification>\n"
            f"  <task_id>{bg_id}</task_id>\n"
            f"  <status>completed</status>\n"
            f"  <command>{task['command']}</command>\n"
            f"  <summary>{summary}</summary>\n"
            f"</task_notification>")
        print(f"  \033[32m[background done] {bg_id}: "
              f"{task['command'][:40]} ({len(output)} chars)\033[0m")
    return notifications


def has_pending_background() -> bool:
    """Non-destructive: True if any background task has completed and is
    waiting to be collected. The inbox poller uses this in its wake condition."""
    with background_lock:
        return any(t["status"] == "completed" for t in background_tasks.values())


# ── Cron Scheduler (from s14, synced) ──

DURABLE_PATH = WORKDIR / ".scheduled_tasks.json"


@dataclass
class CronJob:
    id: str
    cron: str        # "0 9 * * *"
    prompt: str      # message to inject when fired
    recurring: bool  # True = recurring, False = one-shot
    durable: bool    # True = persist to disk


scheduled_jobs: dict[str, CronJob] = {}
cron_queue: list[CronJob] = []
cron_lock = threading.Lock()
_last_fired: dict[str, str] = {}  # job_id → "YYYY-MM-DD HH:MM"


def _cron_field_matches(field: str, value: int) -> bool:
    """Match a single cron field against a value."""
    if field == "*":
        return True
    if field.startswith("*/"):
        step = int(field[2:])
        return step > 0 and value % step == 0
    if "," in field:
        return any(_cron_field_matches(f.strip(), value)
                   for f in field.split(","))
    if "-" in field:
        lo, hi = field.split("-", 1)
        return int(lo) <= value <= int(hi)
    return value == int(field)


def cron_matches(cron_expr: str, dt: datetime) -> bool:
    """Check if a 5-field cron expression matches the given datetime.
    Standard cron semantics: DOM and DOW use OR when both are constrained."""
    fields = cron_expr.strip().split()
    if len(fields) != 5:
        return False
    minute, hour, dom, month, dow = fields
    dow_val = (dt.weekday() + 1) % 7  # Python Monday=0 → cron Sunday=0

    m = _cron_field_matches(minute, dt.minute)
    h = _cron_field_matches(hour, dt.hour)
    dom_ok = _cron_field_matches(dom, dt.day)
    month_ok = _cron_field_matches(month, dt.month)
    dow_ok = _cron_field_matches(dow, dow_val)

    # Minute, hour, month must all match
    if not (m and h and month_ok):
        return False
    # DOM and DOW: if both constrained, either matching is enough (OR)
    dom_unconstrained = dom == "*"
    dow_unconstrained = dow == "*"
    if dom_unconstrained and dow_unconstrained:
        return True
    if dom_unconstrained:
        return dow_ok
    if dow_unconstrained:
        return dom_ok
    return dom_ok or dow_ok


def _validate_cron_field(field: str, lo: int, hi: int) -> str | None:
    """Validate a single cron field value is within [lo, hi]."""
    if field == "*":
        return None
    if field.startswith("*/"):
        step_str = field[2:]
        if not step_str.isdigit():
            return f"Invalid step: {field}"
        step = int(step_str)
        if step <= 0:
            return f"Step must be > 0: {field}"
        return None
    if "," in field:
        for part in field.split(","):
            err = _validate_cron_field(part.strip(), lo, hi)
            if err: return err
        return None
    if "-" in field:
        parts = field.split("-", 1)
        if not parts[0].isdigit() or not parts[1].isdigit():
            return f"Invalid range: {field}"
        a, b = int(parts[0]), int(parts[1])
        if a < lo or a > hi or b < lo or b > hi:
            return f"Range {field} out of bounds [{lo}-{hi}]"
        if a > b:
            return f"Range start > end: {field}"
        return None
    if not field.isdigit():
        return f"Invalid field: {field}"
    val = int(field)
    if val < lo or val > hi:
        return f"Value {val} out of bounds [{lo}-{hi}]"
    return None


def validate_cron(cron_expr: str) -> str | None:
    """Validate a cron expression. Returns error message or None."""
    fields = cron_expr.strip().split()
    if len(fields) != 5:
        return f"Expected 5 fields, got {len(fields)}"
    bounds = [(0, 59), (0, 23), (1, 31), (1, 12), (0, 6)]
    names = ["minute", "hour", "day-of-month", "month", "day-of-week"]
    for i, (field, (lo, hi), name) in enumerate(zip(fields, bounds, names)):
        err = _validate_cron_field(field, lo, hi)
        if err:
            return f"{name}: {err}"
    return None


def save_durable_jobs():
    """Persist durable jobs to .scheduled_tasks.json."""
    durable = [asdict(j) for j in scheduled_jobs.values() if j.durable]
    DURABLE_PATH.write_text(json.dumps(durable, indent=2))


def load_durable_jobs():
    """Load durable jobs from disk on startup."""
    if not DURABLE_PATH.exists():
        return
    try:
        jobs = json.loads(DURABLE_PATH.read_text())
        for j in jobs:
            job = CronJob(**j)
            err = validate_cron(job.cron)
            if err:
                print(f"  \033[31m[cron] skipping invalid job {job.id}: {err}\033[0m")
                continue
            scheduled_jobs[job.id] = job
        valid = [j for j in jobs if j["id"] in scheduled_jobs]
        if valid:
            print(f"  \033[35m[cron] loaded {len(valid)} durable job(s)\033[0m")
    except Exception:
        pass


def schedule_job(cron: str, prompt: str, recurring: bool = True,
                 durable: bool = True) -> CronJob | str:
    """Register a new cron job. Returns CronJob or error string."""
    err = validate_cron(cron)
    if err:
        return err
    job = CronJob(
        id=f"cron_{random.randint(0, 999999):06d}",
        cron=cron, prompt=prompt,
        recurring=recurring, durable=durable,
    )
    with cron_lock:
        scheduled_jobs[job.id] = job
    if durable:
        save_durable_jobs()
    print(f"  \033[35m[cron register] {job.id} '{cron}' → {prompt[:40]}\033[0m")
    return job


def cancel_job(job_id: str) -> str:
    """Cancel a cron job."""
    with cron_lock:
        job = scheduled_jobs.pop(job_id, None)
    if not job:
        return f"Job {job_id} not found"
    if job.durable:
        save_durable_jobs()
    print(f"  \033[31m[cron cancel] {job_id}\033[0m")
    return f"Cancelled {job_id}"


def cron_scheduler_loop():
    """Independent daemon thread: poll every 1s, fire matching jobs.
    Individual job errors are caught to prevent one bad job from
    killing the entire scheduler thread."""
    while True:
        time.sleep(1)
        now = datetime.now()
        # Date-aware marker prevents daily jobs from skipping on day 2+
        minute_marker = now.strftime("%Y-%m-%d %H:%M")
        with cron_lock:
            for job in list(scheduled_jobs.values()):
                try:
                    if cron_matches(job.cron, now):
                        if _last_fired.get(job.id) != minute_marker:
                            cron_queue.append(job)
                            _last_fired[job.id] = minute_marker
                            print(f"  \033[35m[cron fire] {job.id} → "
                                  f"{job.prompt[:40]}\033[0m")
                        if not job.recurring:
                            scheduled_jobs.pop(job.id, None)
                            if job.durable:
                                save_durable_jobs()
                except Exception as e:
                    print(f"  \033[31m[cron error] {job.id}: {e}\033[0m")


def consume_cron_queue() -> list[CronJob]:
    """Consume fired jobs from cron_queue (called by agent_loop)."""
    with cron_lock:
        fired = list(cron_queue)
        cron_queue.clear()
    return fired


# Load durable jobs on startup, then start scheduler thread
load_durable_jobs()
threading.Thread(target=cron_scheduler_loop, daemon=True).start()
print("  \033[35m[cron] scheduler thread started\033[0m")


# Cron tool handlers

def run_schedule_cron(cron: str, prompt: str,
                      recurring: bool = True, durable: bool = True) -> str:
    result = schedule_job(cron, prompt, recurring, durable)
    if isinstance(result, str):
        return f"Error: {result}"
    return f"Scheduled {result.id}: '{cron}' → {prompt}"


def run_list_crons() -> str:
    with cron_lock:
        jobs = list(scheduled_jobs.values())
    if not jobs:
        return "No cron jobs. Use schedule_cron to add one."
    lines = []
    for j in jobs:
        tag = "recurring" if j.recurring else "one-shot"
        dur = "durable" if j.durable else "session"
        lines.append(f"  {j.id}: '{j.cron}' → {j.prompt[:40]} "
                     f"[{tag}, {dur}]")
    return "\n".join(lines)


def run_cancel_cron(job_id: str) -> str:
    return cancel_job(job_id)


# ── MessageBus + Team Protocols (s15 new) ──

MAILBOX_DIR = WORKDIR / ".mailboxes"
MAILBOX_DIR.mkdir(exist_ok=True)
MAILBOX_ROOT = MAILBOX_DIR.resolve()
VALID_AGENT_NAME = re.compile(r"^[A-Za-z0-9_-]{1,64}$")


def is_valid_agent_name(name: str) -> bool:
    return bool(VALID_AGENT_NAME.fullmatch(name))


class MessageBus:
    """Thread-safe file mailboxes with destructive reads."""

    def __init__(self):
        self._lock = threading.RLock()
        self._changed = threading.Condition(self._lock)

    def _path(self, agent: str) -> Path:
        if not is_valid_agent_name(agent):
            raise ValueError(f"Invalid mailbox recipient: {agent!r}")
        path = (MAILBOX_DIR / f"{agent}.jsonl").resolve()
        if not path.is_relative_to(MAILBOX_ROOT):
            raise ValueError(f"Mailbox path escapes directory: {agent!r}")
        return path

    def _read_unlocked(self, agent: str) -> list[dict]:
        inbox = self._path(agent)
        if not inbox.exists():
            return []
        msgs = [json.loads(line) for line in inbox.read_text().splitlines()
                if line.strip()]
        inbox.unlink()
        return msgs

    def send(self, from_agent: str, to_agent: str, content: str,
             msg_type: str = "message", metadata: dict | None = None):
        msg = {"from": from_agent, "to": to_agent,
               "content": content, "type": msg_type,
               "ts": time.time(), "metadata": metadata or {}}
        with self._changed:
            with open(self._path(to_agent), "a") as f:
                f.write(json.dumps(msg, ensure_ascii=False) + "\n")
            self._changed.notify_all()
        print(f"  \033[33m[bus] {from_agent} → {to_agent}: "
              f"({msg_type}) {content[:50]}\033[0m")

    def read_inbox(self, agent: str) -> list[dict]:
        with self._lock:
            return self._read_unlocked(agent)

    def peek(self, agent: str) -> bool:
        with self._lock:
            inbox = self._path(agent)
            return inbox.exists() and inbox.stat().st_size > 0

    def wait_for_messages(self, agent: str,
                          timeout: float | None = None) -> list[dict]:
        """Block until the agent has messages or timeout expires."""
        deadline = None if timeout is None else time.monotonic() + timeout
        with self._changed:
            while not self.peek(agent):
                remaining = (None if deadline is None
                             else deadline - time.monotonic())
                if remaining is not None and remaining <= 0:
                    return []
                self._changed.wait(remaining)
            return self._read_unlocked(agent)


BUS = MessageBus()

# working | waiting_approval | idle | stopping
active_teammates: dict[str, str] = {}
plan_gates: dict[str, str] = {}
plan_request_ids: dict[str, str] = {}
team_lock = threading.RLock()


@dataclass
class ProtocolState:
    request_id: str
    type: str
    sender: str
    target: str
    status: str
    payload: str
    created_at: float = field(default_factory=time.time)


pending_requests: dict[str, ProtocolState] = {}


def new_request_id() -> str:
    while True:
        request_id = f"req_{random.randint(0, 999999):06d}"
        if request_id not in pending_requests:
            return request_id


def match_response(response_type: str, request_id: str, approve: bool,
                   from_agent: str, to_agent: str) -> bool:
    """Match one protocol response to one pending request."""
    with team_lock:
        state = pending_requests.get(request_id)
        if not state:
            print(f"  \033[31m[protocol] unknown request_id: {request_id}\033[0m")
            return False
        expected = {
            "shutdown": "shutdown_response",
            "plan_approval": "plan_approval_response",
        }[state.type]
        if response_type != expected:
            print(f"  \033[31m[protocol] expected {expected}, "
                  f"got {response_type}\033[0m")
            return False
        if from_agent != state.target or to_agent != state.sender:
            print(f"  \033[31m[protocol] {request_id} responder mismatch\033[0m")
            return False
        if state.status != "pending":
            print(f"  \033[33m[protocol] {request_id} already "
                  f"{state.status}\033[0m")
            return False
        state.status = "approved" if approve else "rejected"
    print(f"  \033[35m[protocol] {request_id} → {state.status}\033[0m")
    return True


def consume_lead_inbox() -> list[dict]:
    """Consume Lead events and update protocol state before model delivery."""
    msgs = BUS.read_inbox("lead")
    for msg in msgs:
        metadata = msg.get("metadata", {})
        request_id = metadata.get("request_id", "")
        if request_id and msg.get("type", "").endswith("_response"):
            match_response(msg["type"], request_id,
                           metadata.get("approve", False),
                           msg.get("from", ""), msg.get("to", ""))
    return msgs


def format_team_events(msgs: list[dict]) -> str:
    lines = []
    for msg in msgs:
        metadata = msg.get("metadata", {})
        request_id = metadata.get("request_id")
        suffix = f" request_id={request_id}" if request_id else ""
        lines.append(
            f"[{msg['type']}{suffix}] {msg['from']}: {msg['content']}"
        )
    return "[Team events]\n" + "\n".join(lines)


def _last_assistant_text(content) -> str:
    for block in content:
        if getattr(block, "type", None) == "text":
            return block.text.strip()
        if isinstance(block, dict) and block.get("type") == "text":
            return str(block.get("text", "")).strip()
    return ""


def _teammate_submit_plan(from_name: str, plan: str) -> str:
    with team_lock:
        if plan_gates.get(from_name) == "pending":
            return "A plan is already waiting for review."
        request_id = new_request_id()
        pending_requests[request_id] = ProtocolState(
            request_id=request_id,
            type="plan_approval",
            sender=from_name,
            target="lead",
            status="pending",
            payload=plan,
        )
        plan_gates[from_name] = "pending"
        plan_request_ids[from_name] = request_id
        active_teammates[from_name] = "waiting_approval"
    BUS.send(from_name, "lead", plan, "plan_approval_request",
             {"request_id": request_id})
    return f"Plan submitted ({request_id}). Wait for Lead's decision."


def _run_teammate_tool(name: str, block, handlers: dict) -> str:
    gate = plan_gates.get(name, "not_required")
    if block.name in {"bash", "write_file"} and gate != "not_required":
        if gate != "approved":
            return (f"Blocked: plan status is {gate}. Submit or revise the "
                    "plan and wait for approval before changing the workspace.")
    handler = handlers.get(block.name)
    return str(handler(**block.input)) if handler else f"Unknown tool: {block.name}"


def apply_plan_response(name: str, msg: dict) -> tuple[bool, str]:
    """Apply only the Lead response for this teammate's current plan."""
    metadata = msg.get("metadata", {})
    request_id = metadata.get("request_id", "")
    with team_lock:
        state = pending_requests.get(request_id)
        expected_id = plan_request_ids.get(name)
        valid = (
            msg.get("from") == "lead"
            and msg.get("to") == name
            and request_id == expected_id
            and state is not None
            and state.type == "plan_approval"
            and state.sender == name
            and state.target == "lead"
            and state.status in {"approved", "rejected"}
            and metadata.get("approve", False)
            == (state.status == "approved")
        )
        if not valid:
            return False, "[Ignored plan response: request mismatch]"
        plan_gates[name] = state.status
        active_teammates[name] = "working"
        plan_request_ids.pop(name, None)
        outcome = state.status
    return True, f"[Plan {outcome}] {msg['content']}"


def apply_shutdown_request(name: str, msg: dict) -> tuple[bool, str]:
    """Accept only a pending shutdown request sent by Lead to this teammate."""
    request_id = msg.get("metadata", {}).get("request_id", "")
    with team_lock:
        state = pending_requests.get(request_id)
        valid = (
            msg.get("from") == "lead"
            and msg.get("to") == name
            and state is not None
            and state.type == "shutdown"
            and state.sender == "lead"
            and state.target == name
            and state.status == "pending"
            and active_teammates.get(name) != "stopping"
        )
        if not valid:
            return False, "[Ignored shutdown request: request mismatch]"
        active_teammates[name] = "stopping"
    return True, request_id


def _teammate_send_message(from_name: str, to: str, content: str) -> str:
    with team_lock:
        if to != "lead" and to not in active_teammates:
            return f"Agent '{to}' is not active"
    BUS.send(from_name, to, content)
    return f"Sent to {to}"


# ── Autonomous Task Discovery (s16 new) ──

IDLE_SCAN_INTERVAL = 2.0


def scan_unclaimed_tasks() -> list[Task]:
    """Return ready tasks without changing ownership."""
    return [
        task for task in list_tasks()
        if (task.status == "pending"
            and task.owner is None
            and can_start(task.id))
    ]


def claim_next_task(name: str) -> Task | None:
    """Claim the first ready task that is still available."""
    for task in scan_unclaimed_tasks():
        result = claim_task(task.id, owner=name)
        if result.startswith("Claimed "):
            return load_task(task.id)
    return None


# ── Teammate Thread ──

def spawn_teammate_thread(name: str, role: str, prompt: str) -> str:
    """Spawn a persistent teammate that alternates between WORK and IDLE."""
    if not is_valid_agent_name(name):
        return ("Invalid teammate name: use 1-64 letters, digits, "
                "underscores, or dashes")
    with team_lock:
        if name in active_teammates:
            return f"Teammate '{name}' already exists"
        active_teammates[name] = "working"
        plan_gates[name] = "not_required"

    system = (f"You are '{name}', a {role}. "
              "Use tools to complete assigned work. "
              "When idle, the runtime may assign a ready task from the shared "
              "board. "
              "When asked for a plan, call submit_plan before bash or "
              "write_file and wait for approval. End each assignment with a "
              "concise result; the runtime delivers it to Lead.")

    def run():
        messages = [{"role": "user", "content": prompt}]
        sub_tools = [
            {"name": "bash", "description": "Run a shell command.",
             "input_schema": {"type": "object",
                              "properties": {"command": {"type": "string"}},
                              "required": ["command"]}},
            {"name": "read_file", "description": "Read file contents.",
             "input_schema": {"type": "object",
                              "properties": {"path": {"type": "string"}},
                              "required": ["path"]}},
            {"name": "write_file", "description": "Write content to a file.",
             "input_schema": {"type": "object",
                              "properties": {"path": {"type": "string"},
                                             "content": {"type": "string"}},
                              "required": ["path", "content"]}},
            {"name": "send_message",
             "description": "Send a message to another agent.",
             "input_schema": {"type": "object",
                              "properties": {"to": {"type": "string"},
                                             "content": {"type": "string"}},
                              "required": ["to", "content"]}},
            {"name": "submit_plan",
             "description": "Submit a work plan for Lead approval.",
             "input_schema": {"type": "object",
                              "properties": {"plan": {"type": "string"}},
                              "required": ["plan"]}},
            {"name": "list_tasks",
             "description": "List tasks on the shared board.",
             "input_schema": {"type": "object", "properties": {},
                              "required": []}},
            {"name": "claim_task",
             "description": "Claim a ready task from the shared board.",
             "input_schema": {"type": "object",
                              "properties": {"task_id": {"type": "string"}},
                              "required": ["task_id"]}},
            {"name": "complete_task",
             "description": "Mark an owned task completed.",
             "input_schema": {"type": "object",
                              "properties": {"task_id": {"type": "string"}},
                              "required": ["task_id"]}},
        ]
        sub_handlers = {
            "bash": run_bash, "read_file": run_read, "write_file": run_write,
            "send_message": lambda to, content: _teammate_send_message(
                name, to, content),
            "submit_plan": lambda plan: _teammate_submit_plan(name, plan),
            "list_tasks": run_list_tasks,
            "claim_task": lambda task_id: claim_task(task_id, owner=name),
            "complete_task": complete_task,
        }

        def handle_messages(inbox: list[dict]) -> bool:
            """Return True when a shutdown request ends the teammate."""
            work_messages = []
            for msg in inbox:
                msg_type = msg.get("type", "message")
                metadata = msg.get("metadata", {})
                request_id = metadata.get("request_id", "")
                if msg_type == "shutdown_request":
                    accepted, notice = apply_shutdown_request(name, msg)
                    if not accepted:
                        work_messages.append(notice)
                        continue
                    request_id = notice
                    BUS.send(name, "lead", "Shutdown acknowledged.",
                             "shutdown_response",
                             {"request_id": request_id, "approve": True})
                    return True
                if msg_type == "plan_approval_response":
                    _, notice = apply_plan_response(name, msg)
                    work_messages.append(notice)
                    continue
                if msg_type == "plan_request":
                    work_messages.append(
                        f"[Plan required] {msg['content']}"
                    )
                    continue
                work_messages.append(
                    f"[Message from {msg['from']}] {msg['content']}"
                )
            if work_messages:
                messages.append({"role": "user",
                                 "content": "\n".join(work_messages)})
            return False

        should_stop = False
        while not should_stop:
            with team_lock:
                active_teammates[name] = "working"
            try:
                response = client.messages.create(
                    model=MODEL, system=system, messages=messages[-20:],
                    tools=sub_tools, max_tokens=8000)
            except Exception as exc:
                BUS.send(name, "lead",
                         f"{type(exc).__name__}: {exc}", "error")
                break
            messages.append({"role": "assistant", "content": response.content})
            if response.stop_reason == "tool_use":
                results = []
                for block in response.content:
                    if block.type != "tool_use":
                        continue
                    output = _run_teammate_tool(name, block, sub_handlers)
                    results.append({"type": "tool_result",
                                    "tool_use_id": block.id,
                                    "content": output})
                messages.append({"role": "user", "content": results})
                continue

            summary = _last_assistant_text(response.content)
            gate = plan_gates.get(name, "not_required")
            if gate != "pending" and summary:
                BUS.send(name, "lead", summary, "result")
            if gate == "pending":
                with team_lock:
                    active_teammates[name] = "waiting_approval"
            else:
                with team_lock:
                    active_teammates[name] = "idle"
                BUS.send(name, "lead", "Waiting for more work.",
                         "idle_notification")

            while True:
                inbox = BUS.wait_for_messages(name, IDLE_SCAN_INTERVAL)
                if inbox:
                    should_stop = handle_messages(inbox)
                    if should_stop or messages[-1]["role"] == "user":
                        break
                    continue

                task = claim_next_task(name)
                if task:
                    messages.append({
                        "role": "user",
                        "content": (
                            f"[Auto-claimed task {task.id}] "
                            f"{task.subject}\n{task.description}"
                        ),
                    })
                    print(f"  \033[32m[idle] {name} claimed "
                          f"{task.id}: {task.subject}\033[0m")
                    break

        with team_lock:
            active_teammates.pop(name, None)
            plan_gates.pop(name, None)
            plan_request_ids.pop(name, None)
        print(f"  \033[32m[teammate] {name} finished\033[0m")

    threading.Thread(target=run, daemon=True).start()
    print(f"  \033[36m[teammate] {name} spawned as {role}\033[0m")
    return f"Teammate '{name}' spawned as {role} (autonomous)"


# ── Lead Team Tools ──

def run_spawn_teammate(name: str, role: str, prompt: str) -> str:
    return spawn_teammate_thread(name, role, prompt)


def run_send_message(to: str, content: str) -> str:
    if to not in active_teammates:
        return f"Teammate '{to}' is not active"
    BUS.send("lead", to, content)
    return f"Sent to {to}"


def run_request_shutdown(teammate: str) -> str:
    if teammate not in active_teammates:
        return f"Teammate '{teammate}' is not active"
    with team_lock:
        request_id = new_request_id()
        pending_requests[request_id] = ProtocolState(
            request_id=request_id,
            type="shutdown",
            sender="lead",
            target=teammate,
            status="pending",
            payload="",
        )
    BUS.send("lead", teammate, "Finish the current step and shut down.",
             "shutdown_request", {"request_id": request_id})
    return f"Shutdown requested from {teammate} ({request_id})"


def run_request_plan(teammate: str, task: str) -> str:
    if teammate not in active_teammates:
        return f"Teammate '{teammate}' is not active"
    with team_lock:
        plan_gates[teammate] = "required"
    BUS.send("lead", teammate, task, "plan_request")
    return f"Plan requested from {teammate}"


def run_review_plan(request_id: str, approve: bool,
                    feedback: str = "") -> str:
    with team_lock:
        state = pending_requests.get(request_id)
        if not state:
            return f"Request {request_id} not found"
        if state.type != "plan_approval":
            return f"Request {request_id} is not a plan"
        if state.status != "pending":
            return f"Request {request_id} already {state.status}"
        if plan_request_ids.get(state.sender) != request_id:
            return f"Request {request_id} is not the current plan"
        state.status = "approved" if approve else "rejected"
    content = feedback or ("Plan approved." if approve
                           else "Revise the plan and submit it again.")
    BUS.send("lead", state.sender, content, "plan_approval_response",
             {"request_id": request_id, "approve": approve})
    return f"Plan {state.status} ({request_id})"


# ── Tool Definitions ──

TOOLS = [
    {"name": "bash", "description": "Run a shell command.",
     "input_schema": {"type": "object",
                      "properties": {
                          "command": {"type": "string"},
                          "run_in_background": {"type": "boolean"}},
                      "required": ["command"]}},
    {"name": "read_file", "description": "Read file contents.",
     "input_schema": {"type": "object",
                      "properties": {"path": {"type": "string"},
                                     "limit": {"type": "integer"}},
                      "required": ["path"]}},
    {"name": "write_file", "description": "Write content to a file.",
     "input_schema": {"type": "object",
                      "properties": {"path": {"type": "string"},
                                     "content": {"type": "string"}},
                      "required": ["path", "content"]}},
    {"name": "create_task",
     "description": "Create a new task with optional blockedBy dependencies.",
     "input_schema": {"type": "object",
                      "properties": {
                          "subject": {"type": "string"},
                          "description": {"type": "string"},
                          "blockedBy": {"type": "array",
                                        "items": {"type": "string"}}},
                      "required": ["subject"]}},
    {"name": "list_tasks",
     "description": "List all tasks with status, owner, and dependencies.",
     "input_schema": {"type": "object", "properties": {},
                      "required": []}},
    {"name": "get_task",
     "description": "Get full details of a specific task by ID.",
     "input_schema": {"type": "object",
                      "properties": {"task_id": {"type": "string"}},
                      "required": ["task_id"]}},
    {"name": "claim_task",
     "description": "Claim a pending task. Sets owner, changes status to in_progress.",
     "input_schema": {"type": "object",
                      "properties": {"task_id": {"type": "string"}},
                      "required": ["task_id"]}},
    {"name": "complete_task",
     "description": "Complete an in-progress task. Reports unblocked downstream tasks.",
     "input_schema": {"type": "object",
                      "properties": {"task_id": {"type": "string"}},
                      "required": ["task_id"]}},
    {"name": "schedule_cron",
     "description": "Schedule a cron job. cron is 5-field: min hour dom month dow.",
     "input_schema": {"type": "object",
                      "properties": {
                          "cron": {"type": "string",
                                   "description": "5-field cron expression"},
                          "prompt": {"type": "string",
                                     "description": "Message to inject when fired"},
                          "recurring": {"type": "boolean",
                                        "description": "True=recurring, False=one-shot"},
                          "durable": {"type": "boolean",
                                      "description": "True=persist to disk"}},
                      "required": ["cron", "prompt"]}},
    {"name": "list_crons",
     "description": "List all registered cron jobs.",
     "input_schema": {"type": "object", "properties": {},
                      "required": []}},
    {"name": "cancel_cron",
     "description": "Cancel a cron job by ID.",
     "input_schema": {"type": "object",
                      "properties": {"job_id": {"type": "string"}},
                      "required": ["job_id"]}},
    {"name": "spawn_teammate",
     "description": "Spawn a teammate agent in a background thread.",
     "input_schema": {"type": "object",
                      "properties": {
                          "name": {
                              "type": "string",
                              "pattern": "^[A-Za-z0-9_-]{1,64}$",
                          },
                          "role": {"type": "string"},
                          "prompt": {"type": "string"}},
                      "required": ["name", "role", "prompt"]}},
    {"name": "send_message",
     "description": "Send a message to a teammate via MessageBus.",
     "input_schema": {"type": "object",
                      "properties": {"to": {"type": "string"},
                                     "content": {"type": "string"}},
                      "required": ["to", "content"]}},
    {"name": "request_shutdown",
     "description": "Ask an active teammate to shut down gracefully.",
     "input_schema": {"type": "object",
                      "properties": {"teammate": {"type": "string"}},
                      "required": ["teammate"]}},
    {"name": "request_plan",
     "description": "Require a teammate to submit a plan before changing files.",
     "input_schema": {"type": "object",
                      "properties": {"teammate": {"type": "string"},
                                     "task": {"type": "string"}},
                      "required": ["teammate", "task"]}},
    {"name": "review_plan",
     "description": "Approve or reject a submitted plan by request_id.",
     "input_schema": {"type": "object",
                      "properties": {
                          "request_id": {"type": "string"},
                          "approve": {"type": "boolean"},
                          "feedback": {"type": "string"}},
                      "required": ["request_id", "approve"]}},
]


# ── Context ──

def update_context(context: dict, messages: list) -> dict:
    """Derive context from real state."""
    memories = ""
    if MEMORY_INDEX.exists():
        content = MEMORY_INDEX.read_text().strip()
        if content:
            memories = content
    return {
        "enabled_tools": [t["name"] for t in TOOLS],
        "workspace": str(WORKDIR),
        "memories": memories,
    }


# ── Agent Loop ──
# Keep the loop focused on the mechanisms introduced in this chapter.
# Fired cron entries are injected at the start of each model turn.

def agent_loop(messages: list, context: dict):
    system = get_system_prompt(context)
    while True:
        # Consume fired cron jobs → inject as messages
        fired = consume_cron_queue()
        for job in fired:
            messages.append({"role": "user",
                             "content": f"[Scheduled] {job.prompt}"})
            print(f"  \033[35m[inject cron] {job.prompt[:50]}\033[0m")

        try:
            response = client.messages.create(
                model=MODEL, system=system, messages=messages,
                tools=TOOLS, max_tokens=8000)
        except Exception as e:
            messages.append({"role": "assistant", "content": [
                {"type": "text",
                 "text": f"[Error] {type(e).__name__}: {e}"}]})
            return

        messages.append({"role": "assistant", "content": response.content})
        if response.stop_reason != "tool_use":
            return

        results = []
        for block in response.content:
            if block.type != "tool_use":
                continue
            print(f"\033[36m> {block.name}\033[0m")

            if should_run_background(block.name, block.input):
                bg_id = start_background_task(block)
                results.append({"type": "tool_result",
                                "tool_use_id": block.id,
                                "content": f"[Background task {bg_id} started] "
                                           f"Result will be available when complete."})
            else:
                output = execute_tool(block)
                print(str(output)[:300])
                results.append({"type": "tool_result",
                                "tool_use_id": block.id,
                                "content": output})

        # Merge background tool results + notifications into one user message
        user_content = list(results)
        bg_notifications = collect_background_results()
        if bg_notifications:
            for notif in bg_notifications:
                user_content.append({"type": "text", "text": notif})
        messages.append({"role": "user", "content": user_content})
        context = update_context(context, messages)
        system = get_system_prompt(context)


if __name__ == "__main__":
    print("s16: autonomous agents")
    print("Enter a question, press Enter to send. Type q to quit.\n")
    history = []
    context = update_context({}, [])

    # input() and a 1s poller (teammate inbox or background results) feed one
    # event queue (issues #291, #46).
    events = queue.Queue()

    def input_reader():
        while True:
            try:
                line = input("\033[36ms16 >> \033[0m")
            except (EOFError, KeyboardInterrupt):
                events.put(("quit", None))
                return
            events.put(("user", line))

    def inbox_poller():
        # Poll ~1s and wake the Lead when async results are ready: teammate
        # inbox messages or completed background tasks. Don't gate on
        # active_teammates: a teammate sends its result and then removes itself,
        # so the final message can outlive its registry entry.
        while True:
            time.sleep(1)
            if BUS.peek("lead") or has_pending_background():
                events.put(("wake", None))

    threading.Thread(target=input_reader, daemon=True).start()
    threading.Thread(target=inbox_poller, daemon=True).start()

    had_teammates = False
    while True:
        kind, payload = events.get()
        if kind == "quit":
            break
        if kind == "user":
            if payload.strip().lower() in ("q", "exit", ""):
                break
            history.append({"role": "user", "content": payload})
        else:  # "wake": teammate inbox or background results are ready
            parts = []
            inbox = consume_lead_inbox()
            if inbox:
                parts.append(format_team_events(inbox))
            bg = collect_background_results()
            parts.extend(bg)
            if not parts:
                continue  # already drained by an earlier wake (idempotent)
            history.append({"role": "user", "content": "\n".join(parts)})
            print(f"\n\033[33m[wake: {len(inbox)} team events + "
                  f"{len(bg)} background "
                  f"-> new turn]\033[0m")

        # One turn for whichever source woke us.
        agent_loop(history, context)
        context = update_context(context, history)
        for block in history[-1]["content"]:
            if getattr(block, "type", None) == "text":
                print(block.text)
            elif isinstance(block, dict) and block.get("type") == "text":
                print(block.get("text", ""))

        # Announce once after all requested shutdowns have completed.
        if active_teammates:
            had_teammates = True
        elif had_teammates and not BUS.peek("lead") and not has_pending_background():
            print("\033[32m[all teammates shut down]\033[0m")
            had_teammates = False
        print()