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AI_InvalidResponseDataError: Multiple reasoning_opaque values in single response (github-copilot + claude-sonnet-4-6) #17011
Description
Bug Report
Version: v1.2.24
Provider: github-copilot
Model: claude-sonnet-4-6 (thinking enabled)
Error
AI_InvalidResponseDataError: Multiple reasoning_opaque values received in a single response. Only one thinking part per response is supported.
Root Cause
In the GitHub Copilot streaming handler, when Claude makes multiple parallel tool calls in agentic mode, the streaming response can send multiple reasoning_opaque delta chunks. The current guard throws instead of concatenating:
if (delta.reasoning_opaque) {
if (reasoningOpaque != null) {
throw new InvalidResponseDataError({ ... });
}
reasoningOpaque = delta.reasoning_opaque;
}Suggested Fix
Concatenate instead of throwing:
if (delta.reasoning_opaque) {
reasoningOpaque = (reasoningOpaque ?? "") + delta.reasoning_opaque;
}Impact
- Breaks all agentic sessions using extended thinking with github-copilot provider
- Any response with parallel tool calls triggers this error
- Workaround: binary-patch the binary (not ideal)
Reacted by Nikolai Kolodziej, Fellipe Utaka, F. Torkashvand and Ivan Bretkin
Activity
rekram1-node commentedon Mar 26, 2026
Can anyone provide steps to reproduce?
mortalYoung commentedon Mar 30, 2026
Same Problem Here.
with model claude-sonnet-4.6(thinking enabled) and provider github-copilot too
rekram1-node commentedon Apr 3, 2026
Can anyone please provide steps to reproduce or if not can u please provide a log of it by sending me:
opencode export > session.jsonthis is a terminal command to run, select the session u got it in, then send me file.rekram1-node commentedon Apr 11, 2026
If anyone can do this plz dm me on x or discord, or join our discord and @ me.
rekram1-node commentedon Apr 15, 2026
I switched github copilot to use messages api, ig if u still see this type of thing. Just do as mentioned above, closing as cant repro for now.
bjornsnoen commentedon Jul 3, 2026
Getting this error now when trying to use fable 5 via github-copilot. I've attached the session log as requested. I'm not allowed to reopen the issue, but it's definitely the same one @rekram1-node
session.json
mikybz commentedon Sep 30, 2026
Great work! I get the same issue locally with sonnet 5.5, and are waiting for the PR to merge.
Seems like the PR need an updated description according to a template before it can be merged.
arweenushka commentedon Oct 23, 2026
getting same error with Claude Opus 5.5 and opencode
rekram1-node commentedon Oct 24, 2026
Should be impossible on latest versions of opencode, perhaps ur on a much older version?
Most v2 versions contain patch
arweenushka commentedon Oct 25, 2026
you are right. i had opencode version 1.8