4 Anthropic Staff Posted Exits in 12 Days; 2 Joined OpenAI

Four people posted on X between 24 October and 5 November 2026 that they had left Anthropic, a span of 12 days by our count of the post dates. Two of them, Cat Wu and Austin Lau, have since posted that they joined OpenAI; OpenAI confirmed Wu’s hire to Business Insider, and Anthropic declined to comment.

This is the first piece in a running tracker of staff moves between Anthropic and OpenAI. It counts only moves confirmed by the person’s own post or by a company statement, and it is the first cluster of exits we have tracked; it is not the first time people have left Anthropic.

Business Pill · The Model and the Harness

A short Business Engineer explainer on the difference between an AI model and the harness around it. It teaches the general idea only and says nothing about the people in this piece.

The Exits, in Their Own Words

Thariq Shihipar posted on 24 October at 04:04 UTC: “I’ve left Anthropic after more than a year of working on Claude Code and seeing it scale larger than I ever imagined.” Shihipar’s X profile now reads “formerly Claude Code @anthropicai” and names no new employer.

Anthony Morris posted on 24 October at 12:33 UTC: “Yesterday was my last day at Anthropic.” Morris wrote, “I created Claude Code on desktop because I believe everyone can be a builder,” and named no new employer.

Cat Wu posted on 3 November at 21:33 UTC: “Friday was my last day at Anthropic.” Friday was 30 October. Wu thanked “the incredible team behind Claude Code, Cowork, and Tag.” We covered the exit in Claude Code’s Cat Wu Leaves Anthropic After Revenue Grew 45x.

What Was Posted on X

Thariq Shihipar posted this at 04:04 UTC on 24 October 2026: ‘I’ve left Anthropic after more than a year of working on Claude Code and seeing it scale larger than I ever imagined.’ The post names no new employer.

Anthony Morris posted this at 12:33 UTC on 24 October 2026: ‘Yesterday was my last day at Anthropic.’ Morris wrote that they created Claude Code on desktop; the post names no new employer.

Cat Wu posted this at 21:33 UTC on 3 November 2026: ‘Friday was my last day at Anthropic.’ Wu thanked the team behind Claude Code, Cowork and Tag.

Wu posted this at 00:25 UTC on 5 November 2026, announcing a move to OpenAI to lead product management for Core Products. OpenAI confirmed the hire to Business Insider.

Austin Lau posted this at 02:01 UTC on 5 November 2026, saying they recently joined OpenAI after helping build Anthropic’s growth function. The post gives no last day at Anthropic.

This post, at 03:09 UTC on 5 November 2026, speculates about why Wu moved. It opens with ‘Allegedly’ and lists four possible reasons, including a pay figure its author calls a guess. None of the reasons is confirmed by Wu, OpenAI or Anthropic, and this piece does not report them as fact.

Haider (@haider1) posted this at 21:45 UTC on 4 November 2026, before Wu’s own post at 00:25 UTC on 5 November about joining OpenAI, counting three people who worked on Claude Code leaving Anthropic in about 10 days: Thariq Shihipar, Anthony Morris and Cat Wu. Each exit is in the table above from the person’s own post: Shihipar wrote of more than a year working on Claude Code, and Morris wrote that they created Claude Code on desktop. Calling Wu ‘the product lead behind claude code and cowork’ is Haider’s description, not a title this piece reports or has verified; Wu’s own post thanked ‘the incredible team behind Claude Code, Cowork, and Tag’. ‘Very curious case’, ‘GIANTS’ and the link to a potential IPO are Haider’s framing, not facts we report.

The account @russhustle00 posted this list at 04:48 UTC on 5 November 2026 under the line ‘AI talent war is heating up’. Its Anthropic entries, Cat Wu and Austin Lau joining OpenAI and Thariq Shihipar and Anthony Morris leaving, are the four people this tracker counts from their own posts. The list also names two OpenAI hires, Jill Hazelbaker and Dan Driscoll, and three OpenAI safety researchers it lists as departures, Tomek Korbak, Mikita Balesni and Jasmine Wang; the update above sets out what we checked. The list’s notes that Hazelbaker was ‘formerly at Uber’ and Driscoll ‘formerly U.S. Army Secretary’, and its wording on the three researchers, such as ‘dismissed over alleged policy violations’ and ‘disputes the company’s justification’, are the poster’s own and are not verified here. ‘Who’s winning the AI talent war?’ is the poster’s question.

The Two Who Joined OpenAI

Wu posted on 5 November at 00:25 UTC: “Some news: I’m joining OpenAI to lead product management for Core Products!” OpenAI confirmed that Wu is joining the company, Business Insider reported, and Wu will report to Tibo Sottiaux, according to an OpenAI representative. Our follow-ups: Cat Wu Joins OpenAI Core Products 27 Hours After Exit Post and OpenAI Confirms Cat Wu Hire; Wu to Report to Tibo Sottiaux.

Austin Lau posted on 5 November at 02:01 UTC that they had “recently joined @OpenAI”, and wrote of Anthropic: “got to help build the growth function, work alongside some really really talented people”. Lau’s X profile reads “growth @openai”. Lau did not give a last day at Anthropic.

What Anthropic’s Filing Says About Key People

Anthropic’s S-1/A, filed on 2 November, lists the loss of key people as a risk. It names “the loss of key personnel, including members of our founding team and senior management team, and key engineering, research, product development, marketing, and sales personnel”. It says such a loss could “have an adverse effect on our business.”

The filing adds that the risk “may be heightened as we continue to scale and mature as an organization”, including for “personnel who may conclude that the objectives that drew them to us have been substantially achieved.” It also says: “under certain of our agreements with suppliers, the loss of certain key personnel could accelerate our obligations or otherwise trigger adverse consequences under such agreements.” The filing does not name the people or the suppliers.

The Theories on X, and What Wu Said

A post on X with about 66,000 views offers four possible reasons for Wu’s move, opening with “Allegedly” and including a pay guess the author labels “my guess”. None of the four reasons is confirmed by Wu, OpenAI or Anthropic, and we do not repeat them as fact. On one related question, Business Insider reported that Wu wrote that they had “no idea” if leaving would allow her to sell her shares earlier than remaining employees, and that it “wasn’t a factor for me.”

Reported, Not Counted

Some posts on X list a fifth person, Sunil Shah, as having left Anthropic; one account posted on 27 October that Shah had left. We could not find a post by Shah confirming it, and we could not read Shah’s X profile, so this tracker does not count Shah.

The Business Lever

As we read it, the lever is product continuity before a listing: three of the four people worked on Claude Code, by their own posts, and the S-1/A itself names the loss of key product personnel as a risk. OpenAI’s president Greg Brockman has said OpenAI had Codex but “no one was talking about it”, which we covered in Brockman Reveals JPMorgan Deal, Puts Enterprise Above 50% and Brockman: OpenAI’s Q3 Run Rate Rose 70%, Enterprise Doubled.

Connecting the Coverage

Our related pieces:

• Anthropic’s S-1/A Obligations Table Peaks at $47.8B in 2029: the filing’s year-by-year obligations table.
• Claude Code’s Cat Wu Leaves Anthropic After Revenue Grew 45x: the exit post.
• OpenAI Confirms Cat Wu Hire; Wu to Report to Tibo Sottiaux: OpenAI’s confirmation.

The Structural Read

As we read the posts, three of the four people describe work on Claude Code, and none gives a reason for leaving.

As we read the filing, Anthropic’s S-1/A already names the loss of key product personnel as a risk, and says some supplier agreements could be affected by the loss of certain key personnel, without naming either.

As we read the count, it is narrow by design: posts by others that report a fifth exit are not counted until the person confirms it.

Three Implications

FOR ANTHROPIC Its S-1/A says the loss of key personnel could have an adverse effect on its business.

FOR OPENAI Wu leads product management for Core Products and Lau works in growth, by their own posts.

FOR THIS TRACKER Each move is counted only when the person posts it or a company confirms it.

The Business Engineer Lens

This story maps onto the Business Engineer framework The Product Overhang Doctrine.

The framework says: “Model capability is exponential; product capability is approximately linear.”

As we read it, the people who turn model capability into product are the linear part of that equation, which is why product-team moves between the two labs are worth tracking. The framework predates these moves and does not discuss them.

What Is Not Established

None of the four gave a reason for leaving in the posts we read, and we make no claim about motives. Shihipar and Morris did not name new employers. Lau did not give a last day at Anthropic. Anthropic declined to comment to Business Insider on Wu. The 12 days is our count of post dates, from 24 October to 5 November; it is not a count of last working days.

The Bottom Line

Four people posted that they had left Anthropic in 12 days, by our count, and two of them, Wu and Lau, posted that they joined OpenAI; OpenAI confirmed Wu’s hire. Anthropic’s own S-1/A says the loss of key personnel could have an adverse effect on its business. This tracker records verified moves in either direction.