initial: Piper TTS default plugin

Runtime monkey-patch that changes tools.tts_tool.DEFAULT_PROVIDER from
'edge' to 'piper' at plugin load time. Zero fork needed.

- plugin.yaml with requires_pip: piper-tts
- __init__.py with _apply_piper_patch() + on_session_start hook
- README with installation and safety notes

README.md

@@ -1,3 +1,57 @@
-# hermes-piper-plugin
+# Hermes Piper Plugin
 
-Hermes TTS plugin — makes Piper the default TTS provider instead of Edge. Runtime monkey-patch, zero fork needed.
+Makes Piper TTS the default provider instead of Microsoft Edge TTS.
+
+**Zero modifications to the Hermes repo.** No fork required. The plugin
+monkey-patches `tools.tts_tool.DEFAULT_PROVIDER` at plugin load time.
+
+## Why
+
+- Piper is local, free, CPU-only — no API key, no cloud dependency
+- Edge TTS requires internet access and ffmpeg for Telegram voice bubbles
+- This eliminates the need to maintain a fork just to change the default
+
+## How it works
+
+```python
+# At plugin load time, this single line runs:
+tools.tts_tool.DEFAULT_PROVIDER = "piper"
+```
+
+That's it. `DEFAULT_PROVIDER` is read at call time, so changing it after
+import is safe. The plugin also logs the effective default at session start.
+
+## Installation
+
+```bash
+# 1. Ensure piper-tts is installed
+pip install piper-tts
+
+# 2. Install the plugin from Gitea
+hermes plugins install ssh://git@code.lazyworkhorse.net:2222/Hermes/hermes-piper-plugin.git
+
+# 3. Restart gateways to load the plugin
+```
+
+## Config
+
+The plugin changes the **default** provider. You can still override per
+session by setting `tts.provider` in `~/.hermes/config.yaml`:
+
+```yaml
+tts:
+  provider: elevenlabs      # override per-session
+  voice: "Adam"             # ElevenLabs voice
+```
+
+## Requires
+
+- `piper-tts` Python package (installed via pip)
+- Piper voice models (downloaded automatically on first use, ~50MB each)
+
+## Safety
+
+- If `piper-tts` is not installed, the TTS tool returns an error asking
+  the user to install it — no silent fallback to Edge
+- Removing the plugin restores the original Hermes default (Edge)
+- No data loss risk. No changes to any file in the Hermes repo.

__init__.py

@@ -0,0 +1,59 @@
+"""
+hermes-piper-plugin (piper)
+
+Overrides Hermes' default TTS provider from Edge to Piper at plugin load
+time. Uses runtime monkey-patching — zero modifications to the Hermes repo.
+"""
+
+from __future__ import annotations
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+_PATCHED = False
+
+
+def _apply_piper_patch() -> None:
+    """Replace Edge default with Piper in TTS tool's provider selection.
+
+    Python module-level constants are mutable — ``DEFAULT_PROVIDER`` is a
+    string that ``_get_provider()`` reads at call time (not import time).
+    Changing it after import is safe and immediately effective.
+    """
+    global _PATCHED
+    if _PATCHED:
+        return
+
+    try:
+        import tools.tts_tool
+
+        old_default = getattr(tools.tts_tool, "DEFAULT_PROVIDER", "edge")
+        tools.tts_tool.DEFAULT_PROVIDER = "piper"
+
+        logger.info("piper-plugin: DEFAULT_PROVIDER changed from '%s' → 'piper'", old_default)
+        _PATCHED = True
+    except ImportError:
+        logger.warning("piper-plugin: tools.tts_tool not importable — patch deferred")
+    except Exception as exc:
+        logger.warning("piper-plugin: failed to patch DEFAULT_PROVIDER: %s", exc)
+
+
+def _on_session_start(**kw):
+    """Log Piper default status at session start (idempotent)."""
+    if not _PATCHED:
+        _apply_piper_patch()
+
+    try:
+        import tools.tts_tool
+        current = getattr(tools.tts_tool, "DEFAULT_PROVIDER", "?")
+        logger.info("piper-plugin: TTS default provider = %s (patched=%s)", current, _PATCHED)
+    except Exception:
+        pass
+
+
+def register(ctx) -> None:
+    """Register Piper default override."""
+    _apply_piper_patch()
+    ctx.register_hook("on_session_start", _on_session_start)
+    logger.info("piper-plugin: registered ✓ (TTS default → piper)")

plugin.yaml

@@ -0,0 +1,11 @@
+name: piper
+version: 1.0.0
+description: >
+  Makes Piper TTS the default provider instead of Edge. Zero fork needed —
+  uses runtime monkey-patching to set DEFAULT_PROVIDER = "piper" at plugin
+  load time. Survives Hermes upgrades without merge conflicts.
+author: "@gortium"
+hooks:
+  - on_session_start
+requires_pip:
+  - piper-tts