fix: blank assistant text with MCP enabled after AI SDK v6 migration#20467
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fix: blank assistant text with MCP enabled after AI SDK v6 migration#20467kkugot wants to merge 1 commit intoanomalyco:devfrom
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The v6 upgrade changed the default unmapped finish reason from 'unknown' to 'other', but the prompt loop continue sets were not updated to match. This caused premature loop exit after MCP tool calls, before the model produced final assistant text. Additionally, the LLM middleware still targeted legacy 'prompt' param key while v6 Responses requests use 'messages' or 'input', causing ProviderTransform.message() to be silently skipped. Fixes anomalyco#20050 Fixes anomalyco#20465
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Issue for this PR
Closes #20465
Type of change
What does this PR do?
Fixes blank assistant text in TUI when MCP servers are enabled, a regression introduced in v1.3.4 by the AI SDK 5 -> 6 upgrade.
Two interacting problems:
The v6 finish-reason adapter changed the default unmapped reason from
unknowntoother. The prompt loop continue sets inprompt.tshadunknownremoved butotherwas never added as a replacement. This causes the loop to exit after MCP tool calls before the model produces final text. MCP amplifies this because tool-enabled requests hit this code path far more often.The LLM middleware in
llm.tstargetedargs.params.promptfor applyingProviderTransform.message(), but v6 Responses requests usemessagesorinput. This meant message normalization was silently skipped on Responses requests.The fix adds
otherto both loop continue sets and transforms all three v6 param shapes in the middleware.How did you verify your code works?
bun test test/session/llm.test.ts— 14 passbun typecheck— no new errorsScreenshots / recordings
N/A — not a UI change, the fix restores existing expected behavior.
Checklist