201 lines
8.2 KiB
Markdown
201 lines
8.2 KiB
Markdown
# Session Log — 2026-02-19
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**Project**: PS_AI_Agent (Unreal Engine 5.5)
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**Machine**: Desktop PC (j_foucher)
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**Working directory**: `E:\ASTERION\GIT\PS_AI_Agent`
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---
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## Conversation Summary
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### 1. Initial Request
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User asked to create a plugin to use the ElevenLabs Conversational AI Agent in UE5.5.
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Reference: existing Convai plugin (gRPC-based, more complex). Goal: simpler version using ElevenLabs.
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Plugin name requested: `PS_AI_Agent_ElevenLabs`.
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### 2. Codebase Exploration
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Explored the Convai plugin source at `ConvAI/Convai/` to understand:
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- Module/settings structure
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- AudioCapture patterns
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- HTTP proxy pattern
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- gRPC streaming architecture (to know what to replace with WebSocket)
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- Convai already had `EVoiceType::ElevenLabsVoices` — confirming the direction
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### 3. Plugin Created
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All source files written from scratch under:
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`Unreal/PS_AI_Agent/Plugins/PS_AI_Agent_ElevenLabs/`
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Files created:
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- `PS_AI_Agent_ElevenLabs.uplugin`
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- `PS_AI_Agent_ElevenLabs.Build.cs`
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- `Public/PS_AI_Agent_ElevenLabs.h` — Module + `UElevenLabsSettings`
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- `Public/ElevenLabsDefinitions.h` — Enums, structs, protocol constants
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- `Public/ElevenLabsWebSocketProxy.h` + `.cpp` — WS session manager
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- `Public/ElevenLabsConversationalAgentComponent.h` + `.cpp` — Main NPC component
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- `Public/ElevenLabsMicrophoneCaptureComponent.h` + `.cpp` — Mic capture
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- `PS_AI_Agent.uproject` — Plugin registered
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Commit: `f0055e8`
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### 4. Memory Files Created
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To allow context recovery on any machine (including laptop):
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- `.claude/MEMORY.md` — project structure + patterns (auto-loaded by Claude Code)
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- `.claude/elevenlabs_plugin.md` — plugin file map + API protocol details
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- `.claude/project_context.md` — original ask, intent, short/long-term goals
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- Local copy also at `C:\Users\j_foucher\.claude\projects\...\memory\`
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Commit: `f0055e8` (with plugin), updated in `4d6ae10`
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### 5. .gitignore Updated
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Added to existing ignores:
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- `Unreal/PS_AI_Agent/Plugins/*/Binaries/`
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- `Unreal/PS_AI_Agent/Plugins/*/Intermediate/`
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- `Unreal/PS_AI_Agent/*.sln` / `*.suo`
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- `.claude/settings.local.json`
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- `generate_pptx.py`
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Commit: `4d6ae10`, `b114ab0`
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### 6. Compile — First Attempt (Errors Found)
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Ran `Build.bat PS_AI_AgentEditor Win64 Development`. Errors:
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- `WebSockets` listed in `.uplugin` — it's a module not a plugin → removed
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- `OpenDefaultCaptureStream` doesn't exist in UE 5.5 → use `OpenAudioCaptureStream`
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- `FOnAudioCaptureFunction` callback uses `const void*` not `const float*` → fixed cast
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- `TArray::RemoveAt(0, N, false)` deprecated → use `EAllowShrinking::No`
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- `AudioCapture` is a plugin and must be in `.uplugin` Plugins array → added
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Commit: `bb1a857`
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### 7. Compile — Success
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Clean build, no warnings, no errors.
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Output: `Plugins/PS_AI_Agent_ElevenLabs/Binaries/Win64/UnrealEditor-PS_AI_Agent_ElevenLabs.dll`
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Memory updated with confirmed UE 5.5 API patterns. Commit: `3b98edc`
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### 8. Documentation — Markdown
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Full reference doc written to `.claude/PS_AI_Agent_ElevenLabs_Documentation.md`:
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- Installation, Project Settings, Quick Start (BP + C++), Components Reference,
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Data Types, Turn Modes, Security/Signed URL, Audio Pipeline, Common Patterns, Troubleshooting.
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Commit: `c833ccd`
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### 9. Documentation — PowerPoint
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20-slide dark-themed PowerPoint generated via Python (python-pptx 1.0.2):
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- File: `PS_AI_Agent_ElevenLabs_Documentation.pptx` in repo root
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- Covers all sections with visual layout, code blocks, flow diagrams, colour-coded elements
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- Generator script `generate_pptx.py` excluded from git via .gitignore
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Commit: `1b72026`
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---
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## Session 2 — 2026-02-19 (continued context)
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### 10. API vs Implementation Cross-Check (3 bugs found and fixed)
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Cross-referenced `elevenlabs_api_reference.md` against plugin source. Found 3 protocol bugs:
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**Bug 1 — Transcript fields wrong:**
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- Type: `"transcript"` → `"user_transcript"`
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- Event key: `"transcript_event"` → `"user_transcription_event"`
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- Field: `"message"` → `"user_transcript"`
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**Bug 2 — Pong format wrong:**
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- `event_id` was nested in `pong_event{}` → must be top-level
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**Bug 3 — Client turn mode messages don't exist:**
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- `"user_turn_start"` / `"user_turn_end"` are not valid API types
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- Replaced: start → `"user_activity"`, end → no-op (server detects silence)
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Commit: `ae2c9b9`
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### 11. SendTextMessage Added
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User asked for text input to agent for testing (without mic).
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Added `SendTextMessage(FString)` to `UElevenLabsWebSocketProxy` and `UElevenLabsConversationalAgentComponent`.
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Sends `{"type":"user_message","text":"..."}` — agent replies with audio + text.
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Commit: `b489d11`
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### 12. Binary WebSocket Frame Fix
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User reported: `"Received unexpected binary WebSocket frame"` warnings.
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Root cause: ElevenLabs sends **ALL WebSocket frames as binary**, never text.
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`OnMessage` (text handler) never fires. `OnRawMessage` must handle everything.
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Fix: Implemented `OnWsBinaryMessage` with fragment reassembly (`BinaryFrameBuffer`).
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Commit: `669c503`
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### 13. JSON vs PCM Discrimination Fix
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After binary fix: `"Failed to parse WebSocket message as JSON"` errors.
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Root cause: Binary frames contain BOTH JSON control messages AND raw PCM audio.
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Fix: Peek at byte[0] of assembled buffer:
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- `'{'` (0x7B) → UTF-8 JSON → route to `OnWsMessage()`
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- anything else → raw PCM audio → broadcast to `OnAudioReceived`
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Commit: `4834567`
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### 14. Documentation Updated to v1.1.0
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Full rewrite of `.claude/PS_AI_Agent_ElevenLabs_Documentation.md`:
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- Added Changelog section (v1.0.0 / v1.1.0)
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- Updated audio pipeline (binary PCM path, not Base64 JSON)
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- Added `SendTextMessage` to all function tables and examples
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- Corrected turn mode docs, transcript docs, `OnAgentConnected` timing
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- New troubleshooting entries
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Commit: `e464cfe`
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### 15. Test Blueprint Asset Updated
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`test_AI_Actor.uasset` updated in UE Editor.
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Commit: `99017f4`
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---
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## Git History (this session)
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| Hash | Message |
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| `f0055e8` | Add PS_AI_Agent_ElevenLabs plugin (initial implementation) |
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| `4d6ae10` | Update .gitignore: exclude plugin build artifacts and local Claude settings |
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| `b114ab0` | Broaden .gitignore: use glob for all plugin Binaries/Intermediate |
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| `bb1a857` | Fix compile errors in PS_AI_Agent_ElevenLabs plugin |
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| `3b98edc` | Update memory: document confirmed UE 5.5 API patterns and plugin compile status |
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| `c833ccd` | Add plugin documentation for PS_AI_Agent_ElevenLabs |
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| `1b72026` | Add PowerPoint documentation and update .gitignore |
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| `bbeb429` | ElevenLabs API reference doc |
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| `dbd6161` | TestMap, test actor, DefaultEngine.ini, memory update |
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| `ae2c9b9` | Fix 3 WebSocket protocol bugs |
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| `b489d11` | Add SendTextMessage |
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| `669c503` | Fix binary WebSocket frames |
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| `4834567` | Fix JSON vs binary frame discrimination |
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| `e464cfe` | Update documentation to v1.1.0 |
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| `99017f4` | Update test_AI_Actor blueprint asset |
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---
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## Key Technical Decisions Made This Session
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| Decision | Reason |
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| WebSocket instead of gRPC | ElevenLabs Conversational AI uses WS/JSON; no ThirdParty libs needed |
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| `AudioCapture` in `.uplugin` Plugins array | It's an engine plugin, not a module — UBT requires it declared |
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| `WebSockets` in Build.cs only | It's a module (no `.uplugin` file), declaring it in `.uplugin` causes build error |
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| `FOnAudioCaptureFunction` uses `const void*` | UE 5.3+ API change — must cast to `float*` inside callback |
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| `EAllowShrinking::No` | Bool overload of `RemoveAt` deprecated in UE 5.5 |
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| `USoundWaveProcedural` for playback | Allows pushing raw PCM bytes at runtime without file I/O |
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| Silence threshold = 30 ticks | ~0.5s at 60fps heuristic to detect agent finished speaking |
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| Binary frame handling | ElevenLabs sends ALL WS frames as binary; peek byte[0] to discriminate JSON vs PCM |
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| `user_activity` for client turn | `user_turn_start`/`user_turn_end` don't exist in ElevenLabs API |
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---
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## Next Steps (not done yet)
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- [ ] Verify mic audio actually reaches ElevenLabs (enable Verbose Logging, test in Editor)
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- [ ] Test `USoundWaveProcedural` underflow behaviour in practice (check for audio glitches)
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- [ ] Test `SendTextMessage` end-to-end in Blueprint
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- [ ] Add lip-sync support (future)
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- [ ] Add session memory / conversation history (future, matching Convai)
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- [ ] Add environment/action context support (future)
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- [ ] Consider Signed URL Mode backend implementation
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