Group chat fails with 'model client not activated' when the manager uses a custom client

A GroupChat with speaker_selection_method="auto" errors as soon as it tries to pick the next speaker when the manager uses a custom model client.

Difficulty

Easy

Time

~5 min

Steps

Fixed in

v0.2.37

Last checked

Oct 17, 2026

Verified fix: PR #2696 merged on 2024-10-11. Fixed in v0.2.37 (first stable release containing the merge commit). Last checked 2026-10-17.

Symptom

A GroupChat with speaker_selection_method="auto" errors as soon as it tries to pick the next speaker when the manager uses a custom model client.

Evidence what you'll see

Error says the model client is not activated
Only with a custom model client registered on the GroupChatManager
Speaker selection set to auto

Cause

GroupChat creates internal helper agents for speaker selection and passes them the manager's llm_config, but never registers the custom client on them.

Fix steps

0 of 2 done

Step 1Upgrade AutoGen on the 0.2 line to a release that includes PR #2696, which registers the custom client on the internal speaker-selection agents.
Step 2Keep registering the custom client on the GroupChatManager itself as before.

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Verify the fix worked

Start the group chat again and confirm the next speaker is chosen without the 'not activated' error.

Sources and credit

Summarized in our own words from these public reports. Credit goes to their authors.

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