| --- |
| license: apache-2.0 |
| base_model: |
| - openai/gpt-oss-20b |
| --- |
| |
| # Chroma Context-1 |
|
|
| Context-1 is a 20B parameter agentic search model trained |
| to retrieve supporting documents for complex, multi-hop |
| queries. It is designed to be used as a retrieval subagent |
| alongside a frontier reasoning model: given a query, |
| Context-1 decomposes it into subqueries, iteratively |
| searches a corpus, and selectively edits its own context |
| to free capacity for further exploration. |
|
|
| Context-1 achieves retrieval performance comparable to |
| frontier LLMs at a fraction of the cost and up to 10x |
| faster inference speed. |
|
|
| **Technical report:** |
| [Chroma Context-1: Training a Self-Editing Search Agent](https://trychroma.com/research/context-1) |
|
|
| ## Model Details |
|
|
| - **Base model:** gpt-oss-20b |
| - **Parameters:** 20B (Mixture of Experts) |
| - **Training:** SFT + RL (CISPO) with a staged curriculum |
| - **Precision:** BF16 (MXFP4 quantized checkpoint coming soon) |
|
|
| ## Key Capabilities |
|
|
| - **Query decomposition:** Breaks complex multi-constraint |
| questions into targeted subqueries. |
| - **Parallel tool calling:** Averages 2.56 tool calls per |
| turn, reducing total turns and end-to-end latency. |
| - **Self-editing context:** Selectively prunes irrelevant |
| documents mid-search to sustain retrieval quality over |
| long horizons within a bounded context window (0.94 |
| prune accuracy). |
| - **Cross-domain generalization:** Trained on web, legal, |
| and finance tasks; generalizes to held-out domains and |
| public benchmarks (BrowseComp-Plus, SealQA, FRAMES, |
| HLE). |
|
|
| ## Important: Agent Harness Required |
|
|
| Context-1 is trained to operate within a specific agent |
| harness that manages tool execution, token budgets, context |
| pruning, and deduplication. **The harness is not yet |
| public.** Running the model without it will not reproduce |
| the results reported in the technical report. |
|
|
| We plan to release the full agent harness and evaluation |
| code soon. In the meantime, the technical report describes |
| the harness design in detail. |
|
|
| ## Citation |
|
|
| ```bibtex |
| @techreport{bashir2026context1, |
| title = {Chroma Context-1: Training a Self-Editing Search Agent}, |
| author = {Bashir, Hammad and Hong, Kelly and Jiang, Patrick and Shi, Zhiyi}, |
| year = {2026}, |
| month = {March}, |
| institution = {Chroma}, |
| url = {https://trychroma.com/research/context-1}, |
| } |
| ``` |
|
|
| ## License |
|
|
| Apache 2.0 |
|
|
