Code mode: only the answer crosses back into context PXI writes a little code, the sandbox next to the data does the heavy lifting, and a small result comes back. Model context window — waiting for the next turn — Context consumed with code mode paging every result into context instead context window exhausted payload, stays in the sandbox what reaches the model Phoenix server the sandboxes run in-process, next to the data GraphQL response code result every experiment run aggregated rows bash virtual shell with a persistent workspace spans.json saved in the workspace for later turns execute sandboxed Python; only the return value comes back all 500 runs stay here, filtered in place executeSql read-only SQL, aggregated before it returns thousands of spans grouped into five rows GraphQL API phoenix-gql writes the response straight to a workspace file REST API experiments · datasets · spans called in-process via call_tool Database spans · traces · experiments read-only for PXI