OpenAI built a hidden task system for ChatGPT inside Excel and PowerPoint files
The unreleased desktop feature turns comments on cells, charts, slides and shapes into threaded assignments that ChatGPT can complete in batches.
By Ryan Merket · Published
RUNTIMEWIRE INVESTIGATION — Scoop
Original reporting by RuntimeWire, based on reverse engineering.
Why it matters
OpenAI is turning document review into delegated agent work: users define tasks in context, batch them, and retain control over whether ChatGPT's edits close the assignment.
Reporting record
Finding
OpenAI has built an unannounced, gated review system in the ChatGPT/Codex desktop client that lets users attach native Office comments or private ChatGPT assignments to specific Excel ranges and PowerPoint elements, batch the assignments, and receive threaded replies after the agent works on the underlying file.
How we verified
Methods: reverse engineering.
RuntimeWire analyzed the production app.asar distributed with OpenAI’s Windows desktop package OpenAI.Codex_26.825.4187.0.
The client contains a feature called “Artifact comments” with two parallel comment systems:
Native Excel and PowerPoint comments, described by the interface as being saved directly into the Office file.
Private ChatGPT comment threads, described in the code as persistent but non-exported artifact comments assigned to ChatGPT.
Users can select an Excel range, chart, PowerPoint slide, shape, or presentation element; leave a file comment; or choose “Ask ChatGPT for a change.” Multiple ChatGPT requests can be placed into an “Add to review” queue and sent together.
The client submits these requests using a dedicated artifact_comment agent-turn trigger. Hidden instructions require ChatGPT to address every assigned thread, edit the artifact when requested, and return exactly one structured artifact-comment-reply for each thread. The client intercepts those replies and places them into the corresponding sidebar thread with pending, unread, resolved, and reopened states.
PowerPoint comment changes are serialized back into PPTX bytes using bundled OpenXML infrastructure. Excel comment changes pass through a durable workbook-update system and are materialized into a new XLSX file. This establishes that native comments are intended to exist in the Office files, rather than only as visual overlays inside ChatGPT.
The system is controlled by feature gate 1246162292 and requires the artifact panel to be expanded to full width. Its presence in a production client does not establish that OpenAI has enabled it for ordinary users.
OpenAI publicly documents file previews, selection-based revisions, separate Excel and PowerPoint add-ins, and comments on webpages in Codex’s browser. RuntimeWire found no public OpenAI documentation describing this threaded Office review system, its private ChatGPT comment layer, its review queue, or its model-reply protocol.
Preserved the production app.asar from the installed Microsoft Store package and calculated its SHA-256 hash.
Extracted the Electron archive without modifying the installed application.
Located the Artifact comments interface by tracing user-facing strings including “Ask ChatGPT for a change,” “Add to review,” “PowerPoint comment,” “Excel comment,” and “New ChatGPT reply.”
Followed comment creation from the artifact renderer into the desktop application’s state and message-handling code.
Traced ChatGPT assignments into the dedicated artifact_comment turn trigger and inspected the hidden response contract used to route agent replies back to individual threads.
Traced native PowerPoint comments through presentation export, OpenXML serialization, and workspace-file writeback.
Traced native Excel comments through workbook-worker operations, durable document updates, conflict handling, XLSX export, and file materialization.
Confirmed that native and ChatGPT-only threads are merged into one sidebar while using different persistence and export behavior.
Compared archived extracted clients. The implementation was absent from builds checked through internal version 26.820.71523 and present by 26.825.32147.
Reviewed OpenAI’s current product documentation and searched the public record for the feature’s exact interface and protocol terminology.
The principal evidence comes from production minified JavaScript and bundled runtime files. Descriptive variable and component names were treated as supporting evidence only when corroborated by executable control flow, interface copy, persistence operations, or model-dispatch behavior.
Tested versions:
- OpenAI Codex Windows package 26.825.4187.0 — internal application version 26.825.32147
Reproduction
RuntimeWire partially reproduced the finding.
Reviewed the unmodified production Windows client and traced the feature across its interface, agent workflow, and Office-file handling code.
File hashes
sha256:22DC7276D4A5616DAA504CE7519955AE420FFA4FB10A234B4DA38F74A4AC403F app.asar — OpenAI.Codex_26.825.4187.0
Company response
RuntimeWire requested comment; the company had not responded by publication time.
OpenAI has built a review system inside its shipping desktop client that turns selected parts of Excel workbooks and PowerPoint presentations into threaded assignments for ChatGPT, according to RuntimeWire's examination of the application package.…