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GitHub Copilot streamed tool-call arguments are obfuscated, stalling agentic turns in Codex clients #989
Closed as not planned
Description
Summary
GitHub Copilot's /responses wire is not protocol-compatible with Responses clients for the vscode-chat integration:
- Streamed
response.function_call_arguments.deltaevents carry ciphertextdeltaplus anobfuscationfield. - Reasoning items ship as
encrypted_content(GitHub's own scheme) with no plaintext summary; clients cannot decrypt them and stay stuck on "thinking". - The response id and every item id are re-encrypted per event, so the terminal
response.completedpayload disagrees with the streamed events (call_idis the only stable field).
Impact
Any Responses-only Copilot model (gpt-5.6-luna, gpt-5.6-sol, gpt-5.6-terra, gpt-5.4, gpt-5.4-mini, gpt-5.5, gpt-5.3-codex — see #748) stalls agentic turns in Codex clients: reasoning never finishes and tool calls are unreadable. Plain text works.
Fix
Provider-scoped SSE rewrite for github-copilot (PR #990): drop ciphertext deltas and re-emit plaintext arguments before done, neutralize encrypted reasoning items with an empty plaintext summary, and pin response/item ids to first-seen values.
Activity
github-actions commentedon Aug 4, 2026
Automated translation bookkeeping — detected language: unknown.
Simon-Opopeee commentedon Aug 4, 2026
Fix implemented and opened: #990
github-actions commentedon Aug 4, 2026
Issue closed: use an issue template
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