feat: support agent selection via environment variables

.env

@@ -5,3 +5,4 @@ MISTLE_PASSWORD=sl-mudbot
 MISTLE_LOGIN_PROMPT=Wie heisst Du denn ("neu" fuer neuen Spieler) ?
 MISTLE_EXIT_COMMAND=schlaf ein
 MISTLE_AGENT_MODE=true
+MISTLE_AGENT=simple

.gitignore

@@ -9,3 +9,6 @@ wheels/
 # Virtual environments
 .venv
 .DS_STORE
+
+# config
+.env

README.md

@@ -0,0 +1,71 @@
+# Mistle Mudbot
+
+Python-based Telnet helper for connecting to MUD servers, handling login flows, and optionally running an automated "agent" alongside interactive play.
+
+## Features
+
+- Lightweight wrapper (`TelnetClient`) around `telnetlib` with sane defaults and context-manager support.
+- Loads credentials and connection settings from a local `.env` file.
+- Interactive console session that mirrors server output and lets you type commands directly.
+- Optional agent mode that runs on a background thread and can dispatch automated commands without blocking manual input.
+- Pluggable agent selection via environment variables (built-in `SimpleAgent`, extendable with custom classes).
+
+## Requirements
+
+- Python 3.10+
+- A reachable Telnet-based MUD server
+
+## Quick Start
+
+1. Create a virtual environment and install dependencies:
+
+   ```bash
+   pip install -e .
+   ```
+
+2. Copy `.env.example` (if available) or create a `.env` file in the project root, then fill in the connection details described below.
+
+3. Run the client:
+
+   ```bash
+   python app.py
+   ```
+
+4. Type commands directly into the console. Press `Ctrl-C` to exit; the client will send any configured shutdown command to the MUD.
+
+## Environment Variables
+
+All variables can be placed in the `.env` file (one `KEY=value` per line) or provided through the shell environment.
+
+| Variable | Required | Description |
+| --- | --- | --- |
+| `MISTLE_HOST` | ✅ | DNS name or IP of the target MUD server. |
+| `MISTLE_PORT` | ✅ | Telnet port number (will be cast to `int`). |
+| `MISTLE_USER` | ❌ | Username or character name; sent automatically after login banner, if provided. |
+| `MISTLE_PASSWORD` | ❌ | Password sent after the username. Leave blank for manual entry. |
+| `MISTLE_LOGIN_PROMPT` | ❌ | Prompt string that signals the client to send credentials (e.g., `"Name:"`). When omitted, the client just waits for the initial banner. |
+| `MISTLE_EXIT_COMMAND` | ❌ | Command issued during graceful shutdown (after pressing `Ctrl-C`). Useful for `quit`/`save` macros. |
+| `MISTLE_AGENT_MODE` | ❌ | Enable agent thread when set to truthy values (`1`, `true`, `yes`, `on`). Defaults to interactive-only mode. |
+| `MISTLE_AGENT` | ❌ | Select which agent class to instantiate when agent mode is active. Accepted values: `simple` (default), `explore` (requires `ExploreAgent` inside `agent.py`), or custom spec `module:ClassName`. |
+
+## Agent Development
+
+- Implement new agents by subclassing `agent.Agent` and overriding `observe()` and `decide()`.
+- Register the agent by either:
+  - Adding the class to `agent.py` and referencing it in `MISTLE_AGENT` (e.g., `explore` if the class is named `ExploreAgent`).
+  - Placing the class elsewhere and configuring `MISTLE_AGENT` to `your_module:YourAgent`.
+- `observe(output)` receives the latest server text; `decide()` returns the next command string or `None` to stay idle.
+- Commands issued by the agent are throttled to one per second so manual commands can still interleave smoothly.
+
+## Danger Zone
+
+- The Telnet session runs until you interrupt it. Make sure the terminal is in a state where `Ctrl-C` is available.
+- When adding new agents, guard any long-running logic to avoid blocking the agent thread.
+
+## Contributing
+
+Feel free to open issues or submit pull requests for additional MUD-specific helpers, new agents, or quality-of-life improvements.
+
+---
+
+Happy MUDding!

agent.py

@@ -30,3 +30,18 @@ class SimpleAgent(Agent):
 
     def decide(self) -> Optional[str]:
         return self.default_command
+
+
+@dataclass
+class ExploreAgent(Agent):
+    """Very small stateful agent that decides which command to run next."""
+
+    default_command: str = "untersuche boden"
+    last_output: str = field(default="", init=False)
+
+    def observe(self, output: str) -> None:
+        if output:
+            self.last_output = output
+
+    def decide(self) -> Optional[str]:
+        return self.default_command

app.py

@@ -2,9 +2,10 @@ import os
 import select
 import sys
 import time
+from importlib import import_module
 from pathlib import Path
 from threading import Event, Lock, Thread
-from typing import Optional
+from typing import Optional, Type
 
 from agent import Agent, SimpleAgent
 from telnetclient import TelnetClient
@@ -129,6 +130,44 @@ def require_env(key: str) -> str:
     return value
 
 
+def build_agent(agent_spec: str) -> Agent:
+    """Instantiate an agent based on ``MISTLE_AGENT`` contents."""
+    normalized = agent_spec.strip()
+    if not normalized:
+        return SimpleAgent()
+
+    key = normalized.lower()
+    if key == "simple":
+        return SimpleAgent()
+
+    if key == "explore":
+        try:
+            module = import_module("agent")
+            agent_cls = getattr(module, "ExploreAgent")
+        except AttributeError as exc:  # pragma: no cover - optional dependency
+            raise RuntimeError("ExploreAgent is not available in agent module") from exc
+        return _instantiate_agent(agent_cls, normalized)
+
+    if ":" in normalized:
+        module_name, class_name = normalized.split(":", 1)
+        if not module_name or not class_name:
+            raise RuntimeError("MISTLE_AGENT must be in 'module:ClassName' format")
+        module = import_module(module_name)
+        agent_cls = getattr(module, class_name)
+        return _instantiate_agent(agent_cls, normalized)
+
+    raise RuntimeError(f"Unknown agent spec '{agent_spec}'.")
+
+
+def _instantiate_agent(agent_cls: Type[Agent], agent_spec: str) -> Agent:
+    if not issubclass(agent_cls, Agent):
+        raise RuntimeError(f"{agent_spec} is not an Agent subclass")
+    try:
+        return agent_cls()
+    except TypeError as exc:
+        raise RuntimeError(f"Failed to instantiate {agent_spec}: {exc}") from exc
+
+
 def login(
     client: TelnetClient,
     *,
@@ -233,6 +272,7 @@ def main() -> int:
     login_prompt = os.environ.get("MISTLE_LOGIN_PROMPT", "")
     exit_command = os.environ.get("MISTLE_EXIT_COMMAND", "")
     agent_mode = os.environ.get("MISTLE_AGENT_MODE", "").lower() in {"1", "true", "yes", "on"}
+    agent_spec = os.environ.get("MISTLE_AGENT", "")
 
     state = SessionState()
     stop_event = Event()
@@ -249,7 +289,7 @@ def main() -> int:
         )
 
         if agent_mode:
-            agent = SimpleAgent()
+            agent = build_agent(agent_spec)
             agent_thread = Thread(
                 target=run_agent_loop,
                 args=(client, state, agent, stop_event),