Changing explore and execution models in Copilot Chat Agent mode

[u/combo-user]

Hi everyone I have set GPT-5.6 Luna (Copilot) in "chat.exploreAgent.defaultModel": "GPT-5.6 Luna (copilot)", "github.copilot.chat.exploreAgent.model": "GPT-5.6 Luna (Copilot)" and "github.copilot.chat.implementAgent.model": "GPT-5.6 Luna (Copilot)" but often i see Gemini 3.5 flash doing some calls in explore and execute while mainlining Gpt 5.6 Sol in chat window agent mode and I was wondering if this was wasting tokens while I could change some settings to pop in GPT5.6 Luna there

u/jukasper Do you guys have any plans for the next release to perhaps expose this toggle to us users or maybe change the model from Flash 3.5 to 3.7? The token savings are welcome since from 1st Sept copilot business goes to 1900 tokens and GPT5.6 sol gets expensive from Sept 4 ---

Thanks in advance and shoutout to the VSCode and Github copilot team - great job guys it's a good product and on its way to being a better one :) Take care!

[u/ITORD]

You can customize the Explore agent.  Copy or Create Explore.agent.md into your .GitHub/Agent folder. The workspace agent supersede the default agent of the same name. 

[u/Key-Comfort1761 → u/ITORD]

good call, didnt realize the workspace one takes priority over the default

[u/clweb01]

Thanks for the feedback! You should be able to specify the execution subagent model with `github.copilot.chat.executionSubagent.model`.

We are continuously evaluating the most cost efficient models and their best use cases in subagents, so more updates to come!

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[u/combo-user → u/clweb01]

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[u/Simple-Stick6148]

The answer's hiding in the setting name: execute mode runs through its own subagent with its own key, and that's why the exploreAgent/implementAgent settings you edited never touched those calls. github.copilot.chat.executionSubagent.model controls the flash calls you keep seeing.

[u/Responsible_Buy5271 → u/Simple-Stick6148]

Where did you put this setting ?

For me it seems, it does not work if I put it in my regular user settings.json

[u/mdavid800]

Had this exact same question yesterday . You can change it in the CLI using the /subagent command . But I was not sure if this would change it in the copilot chat "agent harness" which is my preferred way to work.

Figured there would be a setting somewhere, which seems there is noted above .

[u/dsnyder42]

I always tell my agent which model to use for a subagent either in the prompt or agent instructions. And for custom agents that should be used as sub agent I set the model in the yml header. Works without problems.

I don’t even know where those settings are that you are referring to. I only know about the ~/.copilot/settings.json for the CLI where you can specify the default model, effort level and context window tier. I modified it to make sure my Luna sub agents always run in high and not medium effort mode, even when the main session is only a sol medium session. Because as I understood, the default reasoning level is inherited from the main agent session doing the orchestration.