Add support for Cartesia STT

[Nash0x7E2]

• Adds support for Cartesia's Ink STT models
• Update TTS to latest sonic release

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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📥 Commits

Reviewing files that changed from the base of the PR and between 55376a9 and 92cf5cb.

📒 Files selected for processing (2)

• plugins/cartesia/tests/test_stt.py
• plugins/cartesia/tests/test_tts.py

🚧 Files skipped from review as they are similar to previous changes (1)

• plugins/cartesia/tests/test_stt.py

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📝 Walkthrough

Walkthrough

The PR adds a Cartesia websocket-based STT plugin (plugins/cartesia/vision_agents/plugins/cartesia/stt.py) that handles audio streaming, turn lifecycle events, and transcript emission. The base STT class in agents-core now imports and registers STT event types from the events module during init. The Cartesia package exports STT alongside TTS, the TTS default model is updated to sonic-3.5, and the package metadata and dependencies are expanded. Tests cover STT start guards, listener failure propagation, turn/transcript sequencing, and TTS defaults. Examples and documentation are revised to reflect Cartesia as the STT provider, removing Deepgram dependencies.

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[coderabbitai]

Actionable comments posted: 6

🧹 Nitpick comments (1)

plugins/cartesia/example/main.py (1)

59-59: ⚡ Quick win

Justify the 3-second sleep or remove it.

The hardcoded 3-second sleep after joining appears arbitrary. If it's a workaround for a race condition or initialization delay, document the reason inline. Otherwise, remove it.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 98f4521f-8248-4496-a681-8305ca49f679

📥 Commits

Reviewing files that changed from the base of the PR and between aeeacb1 and 0405cb4.

⛔ Files ignored due to path filters (1)

• uv.lock is excluded by !**/*.lock

📒 Files selected for processing (13)

• agents-core/vision_agents/core/stt/stt.py
• plugins/cartesia/README.md
• plugins/cartesia/example/README.md
• plugins/cartesia/example/main.py
• plugins/cartesia/example/narrator-example.py
• plugins/cartesia/example/pyproject.toml
• plugins/cartesia/pyproject.toml
• plugins/cartesia/tests/test_stt.py
• plugins/cartesia/tests/test_tts.py
• plugins/cartesia/vision_agents/plugins/cartesia/__init__.py
• plugins/cartesia/vision_agents/plugins/cartesia/stt.py
• plugins/cartesia/vision_agents/plugins/cartesia/tts.py
• tests/test_stt_events.py

[coderabbitai]

⚠️ Potential issue | 🟠 Major | ⚡ Quick win

Guard start() state before opening the websocket.

Line 79 opens the socket and Line 89 emits connected before the duplicate-start guard in super().start() runs on Line 90. A repeat start() can fail after side effects, leaving inconsistent runtime state.

Suggested fix

 async def start(self) -> None:
     """Open the Cartesia realtime STT websocket."""
+    if self.started:
+        raise ValueError("STT is already started, dont call this method twice")
+    if self.closed:
+        raise ValueError("STT is closed and cannot be started")
     if self.connection is not None:
         logger.warning("Cartesia STT connection already started")
         return
 
     url = self._build_websocket_url()
     self.connection = await asyncio.wait_for(
         websockets.connect(
             url,
             additional_headers={"X-API-Key": self.api_key},
         ),
         timeout=10.0,
     )
 
     self._listen_task = asyncio.create_task(self._listen())
     self._connection_ready.set()
     self._on_connected()
     await super().start()