Your AI assistant went quiet: OpenAI switched the Assistants API off

The bot stopped answering and nothing else changed

The clearest account of what this felt like came from someone whose help bot stopped the day after the shutdown:

The Assistants API shut down yesterday and took our help bot with it. I have the assistant ID but every read path 404s. Is there any remaining way to retrieve a retired assistant's instructions - a grace-period endpoint, a dashboard export, a support request? Or is it deleted for good?

• a developer, Recovering an Assistant's instructions after the Assistants API shutdown, OpenAI Developer Community, 27 August 2026

The answer he got was blunt:

I'm afraid the end of Assistants API meant just that. [...] Not even an error message body to return, just an invalid URL path.

• another developer, same thread, OpenAI Developer Community, 27 August 2026

And then, in a follow-up post, the sentence that explains why a year of notice did not help:

It took us only some hours from OpenAI deleted the endpoint to our users complaining about it.

Sure I knew about the API being deprecated, but I didn't know we were using it.

• the thread's author, same thread, OpenAI Developer Community, 28 August 2026

That is the failure mode worth taking seriously. The announcement was addressed to developers who call the API directly. The people who lost a working chatbot mostly built it inside a no-code platform years ago, and had no reason to know which OpenAI product was underneath.

What was switched off, and when

OpenAI's deprecations page states the notice and the date:

On August 26th, 2025, we notified developers using the Assistants API of its deprecation and removal from the API one year later, on August 26, 2026.

• Deprecations, OpenAI API documentation

The shutdown table on that page names two replacements, not one: the Responses API and the Conversations API. The migration guide confirms the state of the old one:

The Assistants API was officially sunset on August 26, 2026, and is no longer available. Use the Responses API for new integrations.

• Assistants to Conversations migration, OpenAI API documentation

Users report the endpoints answering 404 on both a single assistant and the list call. OpenAI does not document what a request to a retired endpoint returns, so treat the specific status code as a report from the field and not as a specification.

How do you find out whether you were using it?

Faster than reading anyone's migration guide: look for the names. The Assistants API surfaced under recognisable labels in each platform, so the audit is a search for those words across your workflows.

If a scenario, Zap or workflow contains one of those, it was built on the API that is now gone. If your bot lives on a website through a widget somebody set up for you, the question goes to whoever set it up, and the useful phrasing is "does this use the OpenAI Assistants API".

Which Zapier actions stopped, and what migrated automatically?

Zapier published the most operationally useful notice of the three platforms. It named the affected operations, seven entries covering actions, searches and dropdowns, and set expectations plainly:

OpenAI is deprecating the Assistants API. Zapier has deprecated all ChatGPT (OpenAI) actions that use it. On August 26, 2026, Zaps using these actions will stop working. If your Zaps use any of the affected actions, review or update them before that date.

• Important update: ChatGPT users - OpenAI Assistants API deprecation, Zapier Help Center, updated 20 July 2026

The part that decides how much work you have is the scope of the automatic migration, and the quantifier in it is doing the work:

Zapier will automatically migrate Zaps that use Conversation With Assistant (Legacy) to the new Conversation action (powered by the OpenAI Responses API). This automatic migration applies only to Zaps that use Conversation With Assistant (Legacy).

• same article, Zapier Help Center

One operation out of seven. And even that one does not resume on its own:

Migrated Zaps are left turned off so you can review them first. For each migrated Zap, confirm the Conversation action is configured correctly, remap fields in later steps if needed, then turn the Zap back on.

• same article, Zapier Help Center

So the person who did nothing does not have a migrated Zap running quietly in the background. They have a Zap that is switched off. For the rest, Zapier is direct about what is available:

Create Assistant, Upload File, Find Assistant, Find or Create Assistant: These have no direct replacement. Rebuild the workflow using current ChatGPT (OpenAI) actions, or redesign it.

• same article, Zapier Help Center

Worth noting how late that clarity arrived. Zapier's earlier page on the same subject, in its 29 May 2026 revision, still said the deprecation was coming "in the first half of 2026" and that "Zapier will notify you closer to the time when a deprecation date is finalized" - nine months after OpenAI had published the date.

What did Make tell its users about the removal?

Make's entire communication on the subject is two sentences in a combined release note dated 21 August 2026, five days before the shutdown:

The Message an Assistant module has been removed from OpenAI in Make. Update any scenarios using this module to a supported alternative.

• OpenAI: Message an Assistant module removed, Make Help Center, updated 21 August 2026

That note does not mention OpenAI's shutdown, does not give the 26 August date, and does not name the alternative. Make's current module list for the OpenAI app does have a Responses and Conversations group, so the replacement exists - it is simply not pointed at from the notice. Make does publish dated deprecation pages for other changes in the same period, including the removal of Cycles on 1 October and a GPT model deprecation in August, so this was a choice about this change rather than a house style.

For anyone rebuilding: the group that replaces it is Responses and Conversations, and the scenario has to be reasoned about rather than swapped, because the old module carried thread state that the new one handles differently.

Does n8n still support OpenAI Assistant operations?

n8n's version of this story is the strangest, and it produced no drama on 26 August at all, because the break had already happened. The Assistant operations are not in node V2. They were left behind in the older node version, and the docs still describe the shutdown as something in the future:

Assistant operations are deprecated in OpenAI node V2, introduced in n8n 1.117.0. OpenAI node V2 supports the OpenAI Responses API, and removes support for the to-be-deprecated Assistants API.

• Assistant operations, n8n Docs, read 6 September 2026

Those operations are still documented, in full, buried several levels deep in the docs, with no notice that calling them now fails. What people actually experienced was the operations disappearing from the node picker after an upgrade, months ago:

A few months ago, I regularly used a feature called "Message an Assistant", which allowed me to trigger an OpenAI Assistant directly within a workflow. However, I can't seem to find it anymore, it no longer appears in the node list, and I haven't found any reference to it in the current documentation.

• a user, Where can i find the "Message an Assistant" Node?, n8n Community, 19 November 2025

And the workaround that circulated has aged badly. It was to pin the node to the older type version so the Assistant operations came back - which means pinning your workflow to an API that has since been switched off. If you did that, the node is still there, still configured, and now calls nothing.

Can you recover assistant instructions or thread history?

This is the part to act on today rather than at leisure. Conversation history stored in threads is not retrievable now that the API is off. OpenAI's own migration guide says so, in a note attached to its own backfill example:

The example below shows how thread history could be migrated before the sunset. The Assistants API call that retrieves thread messages no longer works; use your stored messages instead.

• Assistants to Conversations migration, OpenAI API documentation

"Use your stored messages instead" assumes you have some. A support bot that kept its transcripts in OpenAI's threads and nowhere else has lost them. The same applies to the assistant definition itself: the instructions, the model choice and the tool configuration lived server-side, and if they were created by hand in the dashboard years ago by somebody who has since left, there is no copy to read back from OpenAI.

One thing worth checking before giving up on a lost definition. If you ever logged your API requests and responses, or sent traces to an observability tool, the instructions and model settings were inside those payloads. That is how the person whose help bot died got his back: his app happened to be shipping traces to a third-party logging tool, and the instructions were sitting in them.

Vector stores are a separate object, and the operator in that thread found his still intact and readable. OpenAI's pages say nothing either way, so treat that as one report rather than a guarantee, and check yours before assuming the retrieval content survived.

What do you migrate an assistant to, and what expires in November?

The guide's mapping is straightforward on the surface: assistants become prompts, threads become conversations, runs become responses, run steps become items. The trap is in the first row, and OpenAI flags it themselves inside the guide:

Reusable prompt objects are also being deprecated. If you use this migration path, review the prompts deprecation timeline before adopting prompt objects in a long-lived integration.

• Assistants to Conversations migration, OpenAI API documentation

The timeline it points at is on the deprecations page, and the date is close:

Nov 30, 2026 - The v1/prompts API and reusable prompt objects are scheduled to shut down.

• Deprecations, OpenAI API documentation

So the obvious reading of step one - move your assistant's configuration into a dashboard prompt object - buys a second migration before the end of November. The durable version is to keep the instructions and model choice in your own configuration, in code or in the workflow itself, where a vendor's object lifecycle cannot reach them.

One more gap worth knowing before you scope the work: the guide's mapping table covers assistants, threads, runs and run steps. File search, vector store management and code interpreter are not addressed in it, so if your assistant used those, the migration guide will not tell you what happens to them.

What to do this week

1. Search every workflow for the names in the table above. Zapier's editor hides the deprecated actions, so search your Zap list rather than the action picker. In Make, search scenarios for the OpenAI module. In n8n, search for nodes with an assistant resource, including any workflow somebody pinned to an older node version.
2. Check whether anything is quietly off. A migrated Zap sits turned off until a person turns it on, which looks identical to a Zap nobody has touched.
3. Find out what your bot is actually answering with right now. If it went quiet, users noticed. If it silently fell back to something else, they may not have, and a bot that answers wrongly is a worse problem than one that stops.
4. Write down the instructions and model settings for every assistant you still have a copy of, into your own files. Check your request logs and any tracing tool first: that is where the operator in that forum thread eventually found his.
5. Rebuild on Responses and Conversations, keeping configuration on your side. Prompt objects in the dashboard are a supported path until 30 November 2026 and then they are not.
6. Decide what happens to old conversation history before you switch. If it matters and it lives only in OpenAI threads, it is already gone; if it matters going forward, store it where you control it.
7. Set a reminder for 30 November 2026 if you touch prompt objects at all.

When this is a job to hand over

Reconnecting one broken step in one Zap is an afternoon, and if you can see which step is red, do it yourself.

It becomes a job when nobody knows which of thirty scenarios still calls the old API, when the assistant definition is lost and the behaviour has to be reconstructed from what the bot used to say, or when the thing that broke is customer-facing and has been broken for a fortnight. That is a bounded piece of work with a known price, which is what Fix S and Fix M are for, and this is the shape the AI agent jobs we take are scoped for: something that worked until a vendor moved, and a business that found out from a customer.

The pattern is not specific to OpenAI, either. Every automation you run sits on somebody else's release schedule, and the notice always arrives addressed to developers.

Sources

• Deprecations - OpenAI API documentation, read 6 September 2026. The one-year notice and the 26 August 2026 removal date, the Responses and Conversations APIs as replacements, and the 30 November 2026 shutdown of the v1/prompts API and reusable prompt objects.
• Assistants to Conversations migration - OpenAI API documentation, read 6 September 2026. The sunset statement, the mapping from assistants, threads, runs and run steps, the callout warning that prompt objects are themselves being deprecated, and the note that the call retrieving thread messages no longer works.
• Important update: ChatGPT users - OpenAI Assistants API deprecation - Zapier Help Center, updated 20 July 2026, read 6 September 2026. The seven affected operations, the automatic migration limited to one of them, migrated Zaps being left turned off, and which actions have no direct replacement.
• ChatGPT (OpenAI) now supports Responses API - Zapier Help Center, updated 29 May 2026, read 6 September 2026. The earlier, vaguer notice describing the deprecation as coming in the first half of 2026 with a date yet to be finalised.
• OpenAI: Message an Assistant module removed - Make Help Center, updated 21 August 2026, read 6 September 2026. The two-sentence removal notice, with no date, cause or named replacement.
• Assistant operations - n8n Docs, read 6 September 2026. Assistant operations documented as deprecated in node V2 and described as calling a "to-be-deprecated" API, eleven days after the shutdown.
• Recovering an Assistant's instructions after the Assistants API shutdown - OpenAI Developer Community, 27-28 August 2026, read 6 September 2026. A live help bot lost on the day, the read paths returning 404, and the admission that knowing about the deprecation is not the same as knowing you depend on it.
• Where can i find the "Message an Assistant" Node? - n8n Community, November 2025 to March 2026, read 6 September 2026. n8n users losing the operations on upgrade, and the community workaround of pinning the older node version.