Response Synthesizers
Learn about response synthesizers and how to implement it effectively.
2 min read
🆕Recently updated
Last updated: 12/9/2025
Response Synthesizers
Response Synthesizers are advanced nodes in InnoSynth-Forjinn designed to combine, summarize, or otherwise process multiple agent, retriever, or tool outputs into a single, coherent answer. They're critical for multi-document QA, ensemble flows, and workflows requiring aggregation, voting, or higher-level synthesis of many results.
Why Use Response Synthesizers?
- Multi-Document/Multi-Answer QA: Combine context chunks into one clear answer.
- Voting/Merging: Aggregate multiple agent/tool outputs (e.g., best of N, consensus).
- Dynamic Aggregation: Build workflows that adapt synthesis logic to response content.
Types of Response Synthesizers
1. Simple Concatenation
- Joins outputs from multiple nodes (e.g., context or results) with separator/prefix
- Used for collating search hits, ensemble model results
2. LLM Summarization
- Passes all results to an LLM with an instruction (“summarize these findings,” “choose the best answer,” etc)
- Useful for producing a human-consumable or just-right-length answer
3. Voting/Judging
- Each path produces a candidate answer; Synthesizer uses another node (VotingAgent, etc.) to select or summarize
- Supports confidence scoring, tie breaking, explainability
4. Custom Logic
- Use custom function node to script your own synthesis logic: e.g., fuzzy matching, stats, or outside data
Example: Multi-Document QA
- Start Node → Retriever: Find 5 context docs
- LLM Node: Each context is sent to LLM for answer generation
- Response Synthesizer Node: Receives 5 answers, passes all to LLM with instruction:
"Here are several proposed answers. Please produce the most accurate and concise summary, using only facts present in the answers." - Output: One unified answer, references all source docs.
Configuration
- Aggregation Logic: Choose concat, LLM summarization, voting, or custom
- Input Paths: Connect each candidate output
- Prompt/Config: (For LLM summarizer or judge)
Troubleshooting
- Contradictory/Conflicted Answers: Tune instruction prompt, use more sophisticated summarization.
- LLM hallucinations: Limit summarizer to only aggregate original passages/candidates.
Best Practices
- Always log candidate/inputs in workflow trace for debugging/audit
- Use with retriever+ensemble flows for highest accuracy
- Annotate with source doc ID for explainability/compliance
Response Synthesizers turn many moving parts into a single clear action—key for multi-modal, multi-path, and high-stakes flows.