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Hello,
when using MS Copilot Notebook, the Custom Instructions appear to be completely ignored, even for very simple directives.
The Notebook Spaces where Custom Instructions worked last year no longer respect the same instructions when asked new questions in the same space. New spaces also fail to apply Custom Instructions despite testing different instructions and varying numbers of files.
Has anyone else experienced Custom Instructions not working in the last few days? Is there a known bug, configuration change, or setting to watch for? I could not find any information so far. Also my colleagues are having the same issue.
Building and customizing solutions using Microsoft 365 Copilot APIs and tools
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I am having the same issue, I have several custom notebooks where the instructions are being ignored. I've even gone as far as asking the agent what my custom instructions are and it says there are no instructions. It's like they aren't being listed at all.
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I'm having the same issue. Completely ignoring the instructions
I received confirmation from a Microsoft contact that this behavior is expected given recent platform changes in Copilot Notebooks.
Current situation
Custom Instructions in Copilot Notebooks are currently not reliably enforced
They may still appear in the UI, but are often not applied at inference time
This affects both new and existing notebooks, even ones that worked previously
The issue is tenant-independent (not a configuration or permission problem)
Reason (high level)
Copilot Notebooks recently moved to a more unified inference pipeline
Notebook-level Custom Instructions are no longer treated as hard system prompts
As a result, they can be overridden or dropped entirely
This regression is not well documented yet, which makes it confusing
Recommended workarounds (for now)
Explicitly restate important instructions in every prompt
Upload a short instruction file (e.g. README / Instructions.md) and refer to it in prompts
Put key instructions in the first user message of a notebook session
What not to rely on
Persistent enforcement of Notebook Custom Instructions across sessions or days
Status
This is a known internal limitation, not a public incident
No public ETA yet for a fix or redesign
Copilot Chat (outside Notebooks) is not affected in the same way
So in short: we’re not doing anything wrong — Custom Instructions in Copilot Notebooks are currently degraded, and prompt-level or file-based instructions are the most reliable workaround or using Copilot Agents.
It seems to be that this is currently a known limitation/regression in Copilot Notebooks due to recent platform changes. Notebook-level Custom Instructions may still show in the UI but are no longer reliably applied at inference time, even in previously working notebooks or new spaces.
AI answer
It seems that there may be issues with the Custom Instructions feature in Microsoft Copilot Notebook. If the Custom Instructions are being ignored, it could be related to the Enhanced personalization control being turned off at the admin level or the Custom instruction control being disabled at the end-user level. When these controls are off, Copilot does not apply the custom instructions, although it does not remove them.
If you and your colleagues are experiencing this issue, it might be beneficial to check with your Microsoft 365 admin to ensure that these settings are properly configured. Additionally, if there have been any recent updates or changes in the system, that could also affect the functionality of Custom Instructions.
For more detailed guidance, you may want to refer to the documentation on personalizing what Microsoft 365 Copilot remembers and how to customize its responses.
References: