OpenAI’s wording on Mermaid diagrams in ChatGPT is narrower than many headlines suggest. The confirmed change applies to Codex task transcripts in ChatGPT for iOS. OpenAI says those transcripts can render Mermaid diagrams inline. The announcement does not establish the same behavior in an ordinary ChatGPT conversation, and it does not specifically confirm Mermaid rendering on iPad.
That distinction matters if you arrived here expecting a general diagram button on every Apple device. This article explains what OpenAI actually announced, what inline rendering changes inside a Codex task, how to make a sensible request without assuming undocumented controls, and where the evidence stops.
What OpenAI confirmed
In its July 20, 2026 product update, OpenAI listed several changes under “ChatGPT for iOS updates.” The relevant line says that support was added for rendering Mermaid diagrams inline in task transcripts. The surrounding notes refer to Codex tasks, interactive forms, task switching, hosts, workspaces, and task-list improvements. Taken together, the context identifies this as a Codex task feature inside the iOS app.
You can read the wording in the official OpenAI release notes. That is the primary source for the scope described here.
“Render inline” describes presentation. Instead of seeing only a text block that contains Mermaid notation, a user may see the resulting diagram in the task transcript. This can make a task result easier to scan on a phone, especially when the output describes a sequence, a branching decision, or relationships between components.
The note does not say that ChatGPT invents a new diagram format. Mermaid remains text-based diagram notation. The announced change concerns how that notation appears in a particular transcript context.
What a Codex task transcript is in this context
The phrase “task transcript” is important. A transcript is the record of the interaction and output associated with a Codex task. It is not a broad synonym for every chat in the ChatGPT app. OpenAI’s note places diagram rendering alongside other Codex task changes, including interactive forms and improvements to task lists and task transitions.
For the reader, the practical difference is simple. If a Codex task produces Mermaid notation in a supported iOS transcript, the app can present the diagram inline. You should not infer that pasting Mermaid text into any standard conversation will produce the same result. It might behave differently, but the cited announcement does not answer that question.
If you need a broader introduction to using Codex outside a narrow coding stereotype, see our guide to Codex for knowledge work, research, and documents. For help finding past material across ChatGPT, the ChatGPT unified search guide covers a separate product feature and should not be confused with task transcript rendering.
How to request a Mermaid diagram without overpromising
OpenAI’s release note confirms rendering, but it does not publish a required prompt formula. There is no source-backed reason to claim that one magic phrase, menu, or button is necessary. A plain request is the safest starting point. Describe the information you want organized, name the type of relationship, and ask for Mermaid notation.
For example, a request could read:
Summarize the task flow as a Mermaid flowchart. Keep the labels short, show the decision points, and include the Mermaid source in the task transcript.
That wording is an example, not an official OpenAI command. It gives the task a clear output shape while avoiding claims about controls that the release note never mentions. If the task returns a diagram inline, compare it with the surrounding transcript. The picture should reflect the actual steps and decisions described in the text.
For a sequence rather than a branching process, you can ask for a Mermaid sequence diagram. For relationships among components, ask for a compact graph. These are writing choices in your request. They are not claims that every diagram type has been separately documented or tested in the iOS app.
A careful workflow for reading the result
Inline rendering is convenient, but the diagram should not replace the transcript. Start with the task’s written result. Identify the actors, actions, and decision points that matter. Then read the diagram in the same order and check whether any label compresses the meaning too far.
- State the subject and the intended diagram form in the task request.
- Ask for short labels so the result remains readable on a phone screen.
- Compare each node or step with the text in the transcript.
- Look for missing branches, reversed arrows, or labels that imply certainty the task did not establish.
- Keep the text version when the diagram will inform code, documentation, or a decision.
This review is especially useful when a flow has exceptions. A neat diagram can hide an unresolved condition simply because the visual layout looks complete. The transcript gives you the context needed to notice that gap.
Do not treat the rendered view as proof that the underlying process is correct. Rendering tells you that the app can display the notation. Accuracy still depends on the task output and on your review of the content.
Where inline diagrams can help
The most natural use is a result that already has structure. A software task may describe how a request moves through services. A debugging task may return a decision tree. A repository review may explain relationships among modules. In each case, a compact diagram can reduce the effort needed to follow the result on a small screen.
Diagrams may also help when you return to a long-running task. A visual summary can act as a map of the transcript, while the text preserves details such as assumptions and unresolved questions. This is a reasonable way to use the feature, but it is not an OpenAI guarantee that Codex will always choose the right structure or preserve every detail automatically.
The feature is less useful when the result is mainly prose, contains many long labels, or changes too often for a snapshot to stay accurate. In those cases, asking for a diagram may add clutter. Use one when relationships are the point, not merely because the transcript can render it.
What the source does not establish
The release note is short, so several boundaries deserve explicit treatment.
- Ordinary ChatGPT chats: OpenAI does not say that Mermaid diagrams render inline in every standard chat. The statement is limited to task transcripts.
- iPad support: The same update mentions improved iPad navigation, but it does not connect that line to Mermaid rendering. An iPad-specific availability claim would go beyond the source.
- A universal rollout: The note does not give plan eligibility, account requirements, regional availability, or a rollout percentage for this item.
- A particular app version: No required version number is stated in the cited note.
- Every Mermaid diagram type: The note says Mermaid diagrams in general, but it does not list or certify individual syntax types.
- Export or editing controls: The announcement does not describe exporting the rendered image, editing it visually, copying source, or changing styles.
Those omissions are not evidence that the capabilities are unavailable. They mean only that this announcement does not confirm them. Product behavior can also change after a release note is published, so the current app and current documentation remain the final references for your account.
Troubleshooting without inventing a hidden setting
If a task transcript shows Mermaid source as plain text, avoid assuming that a secret toggle exists. The official note does not document one. First, confirm that you are looking at a Codex task transcript in ChatGPT for iOS rather than an ordinary conversation. Then check whether the output is actually Mermaid notation and whether the task completed normally.
You can ask the task to return a smaller, simpler diagram and to include the source. That may help distinguish a complicated output from a presentation issue, but it is not a guaranteed fix. You can also consult the current product documentation or support information for account-specific behavior. Without a source, claims about reinstalling the app, changing a plan, enabling an experimental menu, or using a precise UI path would be guesswork, so this guide does not prescribe them.
How to describe the feature accurately
When sharing this update with colleagues or readers, use wording that keeps the product boundary intact:
ChatGPT for iOS can render Mermaid diagrams inline in Codex task transcripts, according to OpenAI’s July 20, 2026 release note.
Avoid saying “ChatGPT now supports Mermaid everywhere” or “Mermaid works on iPhone and iPad chats.” Neither statement follows from the source. Accurate wording may sound less dramatic, but it helps users understand where to look and prevents a task-specific update from becoming a false platform-wide promise.
FAQ
Can every ChatGPT chat on iPhone render Mermaid diagrams?
The cited OpenAI note does not confirm that. It specifically says Mermaid diagrams render inline in task transcripts, and the surrounding context is about Codex tasks in ChatGPT for iOS.
Does the announcement confirm Mermaid diagrams on iPad?
No. The update separately mentions an iPad navigation improvement, but it does not explicitly say that Mermaid diagram rendering is supported on iPad. The existing page URL is preserved, but the article title and claims have been corrected to match the source.
Do I need a special Mermaid prompt?
OpenAI does not provide a required prompt in the release note. You can make a plain-language request for a Mermaid flowchart, sequence diagram, or graph, then review the returned source and visual against the transcript.
Can I export or edit the rendered diagram?
The cited announcement does not document export or visual editing controls. Check the current app and official documentation for any later additions rather than assuming those tools are part of the July update.
The useful takeaway
The confirmed feature is modest and specific: Mermaid diagrams can render inline in ChatGPT for iOS Codex task transcripts. That can make structured task output easier to read on a phone. It does not, by itself, establish Mermaid rendering in ordinary chats, iPad support, export tools, account eligibility, or complete coverage of Mermaid syntax. Ask for a clear diagram when the task benefits from one, keep the source and transcript nearby, and judge the visual by whether it accurately represents the work.