[nicho810]

Summary

handleStream returns as soon as a chunk carries a terminal finish reason (stop, length, refusal). Tool call deltas and media in that chunk are already collected first (see TestHandleStream_ToolCallAndStopInSameChunk and TestHandleStream_MediaInTerminalChunkIsAccumulated), but delta.content and delta.reasoning_content are handled after the early return, so text in the terminal chunk is dropped.

Some OpenAI-compatible endpoints do send the last content delta together with finish_reason and usage. DeepSeek V4.1 Flash does it on part of its replies: a stream ends with "mar", then {"content":"igold","finish_reason":"stop","usage":{...}}, and docker-agent prints mar. (The OpenAI adapter only holds back stop / length when the chunk has no usage, so a chunk that carries usage reaches this path.)

This moves the reasoning, thinking-signature and content handling above the terminal finish-reason check, so they are collected before the early return. Behaviour for chunks without a finish reason is unchanged, and the tool-call short-circuit above is untouched.

I work on cheapaimodel, an OpenAI-compatible gateway, where this showed up while testing the provider alias in #4764.

Testing

• New TestHandleStream_ContentInTerminalChunkIsAccumulated (stop and length): fails on main ("mar" instead of "marigold", empty reasoning) and passes with this change.
• go vet ./pkg/runtime/ clean; go test ./pkg/runtime/... passes except TestDoCompactAfterHookFires, which fails the same way on main in my environment (golang:1.27 container).
• Live: a filesystem-toolset agent on deepseek-v4-1-flash answered mar / marig on main (2 of 2 runs) and the full word in 6 of 6 runs with this change.

[aheritier]

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[aheritier]

👋 Some commits in this PR are not signed and verified by GitHub. Please sign your commits with a GPG or SSH key registered in your GitHub account, then force-push.\n\nCommits that are not verified: df70107\n\nSee GitHub’s guide on signing commits for setup instructions. I’ve added status/needs-signed-commits; it will be removed automatically once every commit in this PR carries a valid GitHub-verified signature.

[Copilot]

🟢 Approval recommended

No active review issues block the change to preserve text and reasoning in terminal stream chunks.

No open issues 🎉

What changed in this PR

Fixes runtime stream handling so text and reasoning sent alongside a terminal finish reason are preserved rather than dropped, addressing truncated replies from some OpenAI-compatible providers.

Changes:

• Collects reasoning, thinking signatures, and text before the terminal-chunk early return.
• Adds regression tests for content and reasoning arriving with stop or length and usage data.

File	Description
pkg/​runtime/​streaming.go	Moves text and reasoning handling before terminal finish-reason processing.
pkg/​runtime/​streaming_test.go	Tests that terminal chunks preserve complete content and reasoning.

_{Review effort: Balanced}

[aheritier]

👋 This PR has merge conflicts with the base branch. Please rebase or merge the latest base branch and resolve them. I've moved it to draft and added ; it'll be picked back up automatically once the conflicts are cleared.