promptAsync background work can lose request instance context

[qz1543706741]

Description

promptAsync starts prompt work in a forked effect and returns 204 immediately. Because the forked prompt effect does not explicitly provide the request's InstanceRef / WorkspaceRef, later background work can run with the default instance context instead of the request instance.

In integrations that depend on project-specific agent configuration, this can make subagent lookup see only default agents and fail to resolve custom agents.

The streaming prompt route already captures and provides the instance/workspace context around the prompt effect. promptAsync should do the same before forking.

Plugins

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OpenCode version

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Steps to reproduce

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Screenshot and/or share link

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Operating System

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Terminal

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[github-actions]

This issue might be a duplicate of existing issues. Please check:

• opencode sdk bug: SubtaskPartInput as input, promptAsync can't find agents under .opencode/agents/* , just can load global config #21659: Same root cause — promptAsync fails to find project-specific agents (.opencode/agents/*) because it does not carry the request's instance/workspace context into the forked effect, resulting in only global config being visible.

If this is the same issue, please consider closing this one and adding any new details to #21659 instead.