Tool output not being passed back to agent
AgentTools
Hey everyone,
I’m running into a consistent issue with Mastra (latest stable version
What’s Happening:
- The agent successfully calls the tool.
- The tool executes normally and produces the correct output.
- But the agent never receives the tool result—the process simply ends quietly with no error.
- No follow-up actions, no continuation, no reasoning loop—just a silent stop after the tool finishes.
What I’ve Checked
- Tool schema & return types are correct
- Agent is properly configured with the tool
- Clear instructions for returning text output
- Logging shows the tool’s return payload is generated
- Happens across multiple tools
- Using latest Mastra version
- Setup: Conversation (RAG) Agent + OpenRouter + AI SDK 5 + useChat hook + fastify server
What I Expected
The agent should consume the tool result and continue its thought/action chain, but the callback never triggers.
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Code Example screenshot attached
Attached langufse screenshot
PS: it was happening on previous version of Mastra as well, but I updated it to see if anything changes.
I’m running into a consistent issue with Mastra (latest stable version
0.24.1What’s Happening:
- The agent successfully calls the tool.
- The tool executes normally and produces the correct output.
- But the agent never receives the tool result—the process simply ends quietly with no error.
- No follow-up actions, no continuation, no reasoning loop—just a silent stop after the tool finishes.
What I’ve Checked
- Tool schema & return types are correct
- Agent is properly configured with the tool
- Clear instructions for returning text output
- Logging shows the tool’s return payload is generated
- Happens across multiple tools
- Using latest Mastra version
- Setup: Conversation (RAG) Agent + OpenRouter + AI SDK 5 + useChat hook + fastify server
What I Expected
The agent should consume the tool result and continue its thought/action chain, but the callback never triggers.
---
Code Example screenshot attached
Attached langufse screenshot
PS: it was happening on previous version of Mastra as well, but I updated it to see if anything changes.
