Skill location + chat agent routing — How can users get routed to the GitHub Copilot Chat agent rather than the Positron Assistant agent?

[jenniferdkatz]

Context:
We're piloting a custom skill at our organization. The skill is followed correctly for some users and silently ignored for others. We've narrowed the cause to a routing difference and have a specific fix-oriented question.

The observable difference
Four users, same Positron version (2026.04.x), same skill at .github/skills/org-specific-skill/SKILL.md, all with GitHub Copilot selected as the language model provider.

Users A and B (skill is followed correctly):

• agent: github.copilot.editsAgent
• responderUsername: "GitHub Copilot"
• extensionId: GitHub.copilot-chat
• Chat invokes the skill via a copilot_readFile tool call
• Skill content is treated as authoritative

Users C and D (skill loads but isn't followed after opening turn):

• agent: positron.assistant.agent
• responderUsername: "Positron Assistant"
• extensionId: positron.positron-assistant
• Skill content appears as prompt:instructionsList (auto-attached)
• Skill identity drops after the opening turn

All four users see "Welcome to Positron Assistant" on opening chat. None have the Copilot Chat extension separately installed. All have GitHub Copilot selected as the provider.

What we've ruled out

• Skill location: tested both .github/skills/{skill-name}/ and .positai/skills/{skill-name}/ per https://posit-dev.github.io/assistant/docs/features/skills/. Behavior is the same in both locations for affected users.
• Skill content: identical SKILL.md across all four users (same git repo)
• Model: all on Claude Sonnet 4.6
• Mode: all in Agent mode
• Chat Settings: All appear to be identical across users
• Extension installation: none of the four users have the GitHub Copilot Chat extension separately installed

Question — how do Users C/D get routed to the Copilot Chat agent?
Assuming this is the issue here - Users A and B's chat requests go through GitHub.copilot-chat and follow the skill correctly. Users C and D's requests go through positron.positron-assistant, which appears to override the Copilot path despite Copilot being the selected provider. We'd like to get C and D onto the same routing as A and B.

Is there a setting, sign-in state, extension activation, or feature flag that controls this routing? Why would identical-looking configurations produce different agent paths?

P.S. Opus 4.7 gave up trying to figure this out and sent me here!! :)

[sharon-wang]

Hey @jenniferdkatz! Thank you for this detailed report :)

Since you've referenced the Posit Assistant docs on skills (https://posit-dev.github.io/assistant/docs/features/skills/), I wonder if you would be up for using Posit Assistant instead of Positron Assistant? Posit Assistant brings together the capabilities of Positron Assistant and Databot into a unified experience, and we are currently working on migrating to this experience. This could be the best path forward for a consistent experience across users, as well as piloting what will be the new AI chat experience in Positron.

1. To get started with Posit Assistant, follow these instructions: https://posit-dev.github.io/assistant/docs/downloads/positron/
2. To migrate your skills, ask Posit Assistant to help migrate your skills from GitHub Copilot/Positron Assistant or directly reference the built-in import-instructions skill in chat

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To close the loop on the routing difference you're seeing -- I think there are likely a couple things at play:

• the Copilot model determines whether it should use a copilot tool, so there can be variance depending on what the model determines. If you want to use Positron Assistant, there is an experimental setting from upstream that could improve this behaviour chat.experimental.useSkillAdherencePrompt
• Positron Assistant doesn't read from .positai/skills/{skill-name}/ -- out of the box, that is supported by Posit Assistant only. But! If you still want to use Positron Assistant, perhaps adding that location to chat.agentSkillsLocations setting might provide some better steering, but it will still be up to the model to ensure it uses the skill
• there could also be a race between GitHub Copilot and Positron Assistant, affecting which one ends up as the agent handling the chat requests