🧑 Human-in-the-Loop (HITL) Support
This release introduces human-in-the-loop functionality for tool execution, allowing users to configure certain tools are requiring approvals or specify per-agent requirements. This feature introduces two new LettaMessage types:
ApprovalRequestMessage(for the agent to request an approval)ApprovalResponseMessage(for the client to either provide or deny an approval)
Example of approving a tool call:
response = client.agents.messages.create(
agent_id=agent.id,
messages=[{
"type": "approval",
"approve": True,
"approval_request_id": "message-abc123",
}]
)See the full documentation here.
📁 Agent File (.af) v2
The Agent File schema has been migrated to a v2 version, and now supportsgroups (multi-agent) and files (#4249).
🔎 Archival memory search
Improvements to archival memory search with support for tags, timestamps, and hybrid search:
- Tag-Based Search and Insert: Agents can now insert and search archival memories with arbitrary string tags (#4300, #4285)
- Temporal Filtering: Support for timestamp-based filtering of archival memories (#4330, #4398)
- Hybrid Search: New archival search endpoint with hybrid search functionality (#4390)
🧠 Model and provider support
- GPT-5 Optimization: Improved GPT-5 support with proper context window handling and reasoning effort configuration (#4344, #4379, #4380)
- DeepSeek Support: Migration of DeepSeek to new agent loop architecture (#4266)
- Enhanced Anthropic Support: Better native reasoning support and tool schema formatting (#4331, #4378)
- Extended Thinking: Fixed various issues with extended thinking mode for Anthropic (#4341)
- MCP Tool Schema: Fixed MCP tool schema formatting for Anthropic streaming (#4378)
- Gemini Improvements: Enhanced error handling and retry logic (#4323, #4397)
🧩 Misc improvements
- Refactored Streaming Logic: Improved streaming route architecture (#4369)
- Better Error Handling: Enhanced error propagation in streaming responses (#4253)
- Tool Return Limits: Reduced default tool return size to prevent token overflow (#4383)
- Embedding Support: Enable overriding embedding config on Agent File import (#4224)
- Tool Type Filtering: Ability to list and filter tools by type (#4036)
- Tool De-duplication: Automatic de-duplication of tool rules (#4282)