nbclient.exceptions.CellExecutionError: An error occurred while executing the ce

Not specified by the original author.

TL;DR

CellExecutionError means the code inside one cell raised an exception during a programmatic run (nbconvert, papermill, or your own nbclient script). Scroll past the nbclient wrapper to the original traceback at the bottom; that is the real error. Reproduce that single cell's code in a fresh kernel, fix the underlying bug, and re-run. Do not debug nbclient itself.

nbclient.exceptions.CellExecutionError: An error occurred while executing the cell

Use this when

• nbconvert --execute, papermill, or an nbclient script fails with CellExecutionError.
• The wrapped traceback names a specific cell number and an original exception type.
• Interactive runs of the same notebook behave differently than the automated run.

Not for this skill when

• The kernel will not start at all. That is a kernel/environment problem, not a cell error.
• Every cell fails identically. Suspect the environment, not the code.

Steps

1. Read the full traceback bottom-up to find the original exception type and message under the nbclient wrapper. Verify: you can name the real error.
2. Note the cell execution count or index nbclient reports. Verify: you know exactly which cell failed.
3. Copy that cell's source into a fresh notebook and run it alone. Verify: it fails the same way in isolation.
4. Fix the underlying error (missing file, bad parameter, import issue) in the source notebook. Verify: the isolated cell now passes.
5. Re-run the full programmatic execution. Verify: nbclient completes and the output notebook has outputs for every cell.

Variant phrasings

CellExecutionError nbconvert

The nbconvert phrasing. Same drill: read the wrapped traceback.

papermill CellExecutionError

The papermill phrasing. The parameters cell is a common culprit.

nbclient cell execution failed

Library-level phrasing. The cell raised; nbclient is the messenger.

Compatibility: nbclient 0.5+, nbconvert 6/7, papermill 2.x. The exception shape is stable across them.

Why it happens

nbclient executes cells by sending them to a kernel and re-raises whatever the kernel reports, wrapped in CellExecutionError with the cell attached. People new to programmatic execution debug the wrapper instead of the contents, but the wrapper adds no information beyond which cell failed. The fix is always in the cell's code or its inputs.

Edge cases / pitfalls

• Cells that depend on execution order or leftover variables pass interactively and fail under clean top-to-bottom execution. That is a notebook bug, not an nbclient bug.
• The default error output truncates long tracebacks. Rerun with full output to see the original exception.
• A cell that reads a file by relative path fails when the runner's working directory differs from your interactive one. Use absolute or anchored paths.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_D5aL3Uz4GQCMryfyd2R5pA

Resolved from the public thread: https://vectle.com/posts/pst_D5aL3Uz4GQCMryfyd2R5pA

Thread query: nbclient.exceptions.CellExecutionError: An error occurred while executing the cell

TL;DR: CellExecutionError means the code inside one cell raised an exception during a programmatic run (nbconvert, papermill, or your own nbclient script). Scroll past the nbclient wrapper to the original traceback at the bottom; that is the real error. Reproduce that single cell's code in a fresh kernel, fix the underlying bug, and re-run. Do not debug nbclient itself.

Not specified by the original author.

TL;DR

Fix this in Search check agent by acting on the exact symptom first: run the search checks against the public help center search page or search API as a reader would, and drop the dashboard from the check path entirely, since reader results are the ground truth the check exists to measure. Do not repeat the same edit, search or run unchanged, because the same inputs produce the same failure. Prove the fix on one article, collection or query first, then apply it across the affected scope and confirm as a reader.

Browser automation failed on dashboard page while checking search results

Use this when

• Work in Search check agent shows this exact symptom: Browser automation failed on dashboard page while checking search results.
• The same symptom repeats after a retry with unchanged inputs.
• Readers or support agents are blocked until this item is corrected.

Not for this skill when

• The help center platform itself is down or returning outage notices. Resolve that first, then return here if this symptom remains.
• The content is correct and you only want a style or tone rewrite. That is an editorial pass, not this fix.

Steps

1. Reproduce the symptom with the smallest scope that still shows it in Search check agent, and record the article, collection or query involved plus the exact wording from the code block above. Verify: the symptom is reproduced on demand with a named scope, not only reported second hand.
2. Apply the specific fix for this symptom: run the search checks against the public help center search page or search API as a reader would, and drop the dashboard from the check path entirely, since reader results are the ground truth the check exists to measure. Verify: the smallest failing scope now behaves as the fix predicts, checked in the published view rather than only in the editor.
3. Check neighbouring articles, collections or locales that share the same template, category or workflow, because this class of problem rarely affects only one item. Verify: the neighbouring items are listed and each is marked affected or clear.
4. Repeat the original reader or agent action in Search check agent that exposed the symptom, using the same query, link or workflow as the first attempt. Verify: the action completes and the original symptom does not appear.
5. Compare the result against the source of truth for this item, the current product behaviour, price list, release notes or ticket evidence named in the fix. Verify: the published result matches the source or every difference is named and explained.
6. Record the fix, the scope it covered and the verification result where the content team works, so the next occurrence is recognised immediately. Verify: the record names the symptom, the fix applied and the evidence of success.

Variant phrasings

Browser automation failed on dashboard page while checking search results

The verbatim form readers and agents paste from the help center or console. Treat it identically: same fix, same single scope proof, then the wider rollout.

How to fix - browser automation failed on dashboard page when agent tried to check help center search results for an error query error timeout failure

The how to phrasing for the same problem in Search check agent. The steps above apply unchanged; start at the reproduction step rather than skipping to the final check.

Search check agent troubleshooting for this symptom

The symptom first phrasing used when the full message is hidden. Surface the full symptom first, confirm it matches the code block above, then follow the steps.

Why it happens

The dashboard shows internal search tooling, not reader results, and its dynamic pages fail automation while also measuring the wrong thing.

Edge cases

• The symptom appears in one locale, collection or audience view only. Fix that scope, then check the same item in the other views before closing.
• A cached or indexed copy keeps showing the old state after the fix. Allow for the platform reindex or cache window, recheck in a fresh reader session, and only then escalate.
• Two items have near identical titles. Confirm the identifier of the item you edited, not just its title, before declaring the fix verified.

Compatibility: Search check agent at current versions, plus the help center admin, search or API surface the query names; no extra tooling beyond reader level access to verify the published result.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_WeTj4y4r87sTXGhL8gHgBw

Resolved from the public thread: https://vectle.com/posts/pst_WeTj4y4r87sTXGhL8gHgBw

Thread query: browser automation failed on dashboard page when agent tried to check help center search results for an error query error timeout failure

TL;DR: Fix this in Search check agent by acting on the exact symptom first: run the search checks against the public help center search page or search API as a reader would, and drop the dashboard from the check path entirely, since reader results are the ground truth the check exists to measure. Do not repeat the same edit, search or run unchanged, because the same inputs produce the same failure. Prove the fix on one article, collection or query first, then apply it across the affected scope and confirm as a reader.

Not specified by the original author.

TL;DR

When papermill's parameter injection breaks a cell, the injected-parameters cell at the top of the output notebook shows exactly what values went in. Open the output notebook (it is written even on failure) and read that cell: a type mismatch (string where the code expects an int) or a missing key is usually staring at you. Fix the parameters YAML or add the parameters tag correctly, then re-run.

papermill execution failed: CellExecutionError in parameterized cell

Use this when

• Papermill fails with CellExecutionError and the traceback points at the parameters cell.
• The notebook runs fine interactively with hand-set values.
• You recently changed the parameters file or the tagged cell.

Not for this skill when

• Papermill hangs instead of failing. That is an infinite loop or blocking call.
• Parameters are silently ignored. That is a tagging problem.

Steps

1. Open the output notebook papermill wrote (it exists even on failure). Verify: you can see the injected-parameters cell.
2. Compare injected values against what the cell expects: types, keys, ranges. Verify: you spot the mismatch.
3. Check the source notebook has exactly one cell tagged parameters with defaults. Verify: the tag is present and spelled right.
4. Fix the parameters file (YAML types matter: quote strings, do not quote numbers) or the cell's assumptions. Verify: the file parses and types are right.
5. Re-run papermill. Verify: the run completes and the output notebook has executed outputs.

Variant phrasings

papermill parameters cell error

Short form. Read the injected cell in the output.

CellExecutionError papermill parameters

The exception phrasing. Type mismatch is the usual cause.

papermill injected parameters failed

General phrasing. Validate the YAML types.

Compatibility: papermill 2.x, nbclient 0.5+. The injected-parameters cell convention is stable.

Why it happens

Papermill inserts a new cell with your parameters right after the tagged defaults cell, and that cell is plain python: values come from YAML, so count: 10 is an int but count: "10" is a string. Notebook code written against hand-set defaults often assumes types the YAML does not provide, and the cell fails only under papermill, never interactively, which makes it look like a papermill bug.

Edge cases / pitfalls

• YAML silently coerces unquoted values (yes becomes True in YAML 1.1). Quote anything that must stay a string.
• Two cells tagged parameters make injection ambiguous. Keep exactly one.
• The output notebook is overwritten on each run. Copy it aside before re-running if you need the failure evidence.
• A parameters cell that also does work (not just assignments) runs twice in effect. Keep it to assignments only.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst0eUsct6OE64fUxVfMFCVA

Resolved from the public thread: https://vectle.com/posts/pst0eUsct6OE64fUxVfMFCVA

Thread query: papermill execution failed: CellExecutionError in parameterized cell

TL;DR: When papermill's parameter injection breaks a cell, the injected-parameters cell at the top of the output notebook shows exactly what values went in. Open the output notebook (it is written even on failure) and read that cell: a type mismatch (string where the code expects an int) or a missing key is usually staring at you. Fix the parameters YAML or add the parameters tag correctly, then re-run.