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fix: blank assistant text - finish-reason regression after AI SDK v6 migration#20467

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kkugot wants to merge 2 commits intoanomalyco:devfrom
kkugot:fix/mcp-finish-reason-20050-20465
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fix: blank assistant text - finish-reason regression after AI SDK v6 migration#20467
kkugot wants to merge 2 commits intoanomalyco:devfrom
kkugot:fix/mcp-finish-reason-20050-20465

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@kkugot kkugot commented Apr 1, 2026 •
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Issue for this PR

Closes #20465

Type of change

  • Bug fix
  • New feature
  • Refactor / code improvement
  • Documentation

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.

Root cause: The v6 finish-reason adapter changed the default unmapped reason from unknown to other. The prompt loop continue sets in prompt.ts had unknown removed but other was 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.

Additional fix: The TUI AssistantMessage component rendered empty space for intermediate assistant messages whose parts were all hidden (completed tools with details off, empty text). Added a reactive visible memo that hides the entire message when no parts would render.

How did you verify your code works?

  • Tested locally with MCP enabled: assistant text renders correctly, symptom gone
  • Tested with MCP disabled: no behavior change
  • bun typecheck — no new errors (only pre-existing ripgrep.ts errors on dev)

Checklist

  • I have tested my changes locally
  • I have not included unrelated changes in this PR

@github-actions github-actions bot added the needs:compliance This means the issue will auto-close after 2 hours. label Apr 1, 2026
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github-actions bot commented Apr 1, 2026

The following comment was made by an LLM, it may be inaccurate:

Potential Related PRs Found:

  1. PR fix(opencode): run transformParams middleware unconditionally for all call types #19558 - "fix(opencode): run transformParams middleware unconditionally for all call types"

  2. PR fix(core): prevent agent loop from stopping after tool calls with OpenAI-compatible providers #14973 - "fix(core): prevent agent loop from stopping after tool calls with OpenAI-compatible providers"

@github-actions github-actions bot removed the needs:compliance This means the issue will auto-close after 2 hours. label Apr 1, 2026
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github-actions bot commented Apr 1, 2026

Thanks for updating your PR! It now meets our contributing guidelines. 👍

@kkugot kkugot force-pushed the fix/mcp-finish-reason-20050-20465 branch 6 times, most recently from df65986 to bf4dbc9 Compare April 2, 2026 07:51
@kkugot kkugot mentioned this pull request Apr 2, 2026
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@kkugot kkugot force-pushed the fix/mcp-finish-reason-20050-20465 branch 5 times, most recently from 5d6eef9 to 49cc60e Compare April 7, 2026 18:50
@github-actions github-actions bot added needs:compliance This means the issue will auto-close after 2 hours. and removed needs:compliance This means the issue will auto-close after 2 hours. labels Apr 7, 2026
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github-actions bot commented Apr 7, 2026

Thanks for updating your PR! It now meets our contributing guidelines. 👍

@kkugot kkugot force-pushed the fix/mcp-finish-reason-20050-20465 branch 2 times, most recently from 8c1272b to 36d92e3 Compare April 10, 2026 10:52
@kkugot kkugot changed the title fix: blank assistant text with MCP enabled after AI SDK v6 migration fix: blank assistant text - finish-reason regression after AI SDK v6 migration Apr 10, 2026
@github-actions github-actions bot mentioned this pull request Apr 11, 2026
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@kkugot kkugot force-pushed the fix/mcp-finish-reason-20050-20465 branch 2 times, most recently from a060a89 to 4e4878b Compare April 13, 2026 13:44
@kkugot kkugot mentioned this pull request Apr 13, 2026
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kkugot commented Apr 13, 2026

I am keeping this branch up-to date with dev, would be thankful if this can be merged. engineers using Oracle Code Assist could not use opencode with Open AI models with responses API because of this bug. This is since version 1.3.4

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rekram1-node commented Apr 13, 2026

@kkugot let me look over this

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rekram1-node reviewed Apr 13, 2026
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Comment thread packages/opencode/src/session/llm.ts Outdated
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rekram1-node commented Apr 13, 2026

The LLM middleware in llm.ts targeted args.params.prompt for applying ProviderTransform.message(), but v6 Responses requests use messages or input. This meant message normalization was silently skipped on Responses requests.

Im not sure this is accurate

@kkugot kkugot force-pushed the fix/mcp-finish-reason-20050-20465 branch 2 times, most recently from 111ecaa to 73eb998 Compare April 14, 2026 16:37
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kkugot commented Apr 14, 2026

Addressed both review comments:

  1. Removed the llm.ts transformParams change entirely. @rekram1-node you were right — the middleware always receives LanguageModelV3CallOptions which only has prompt. The messages/input keys only exist inside model implementations after getArgs() converts, but transformParams runs before that. The first commit now only touches prompt.ts.

  2. Updated PR description — removed the inaccurate claim about v6 Responses using different param keys.

The PR now has two commits:

  • prompt.ts: adds "other" to the two finish-reason continue sets (the actual bug fix)
  • index.tsx: hides empty intermediate assistant messages in the TUI (prevents blank space from rendered-but-empty message nodes)

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rekram1-node commented Apr 14, 2026

Why does your provider not send valid stop reasons, we cant just continue on all others i dont think, there are many cases that can trigger this afaik

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kkugot commented Apr 14, 2026 •
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Why does your provider not send valid stop reasons, we cant just continue on all others i dont think, there are many cases that can trigger this afaik

It does, we use OpenAI (@ai-sdk/openai) via responses API through enterprise layer and it works well in Codex and other harnesses. But your question is valid and I am taking it to discuss if there is any modification to stop reasons.

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kkugot commented Apr 14, 2026

The AI SDK 6 upgrade dropped support of "unknown" but has not added support of "other" in full (which is valid reason in V6)

@kkugot kkugot force-pushed the fix/mcp-finish-reason-20050-20465 branch from 73eb998 to c6193db Compare April 14, 2026 18:55
kostiantyn-kugot added 2 commits April 15, 2026 11:41
fix: blank assistant text with MCP enabled after AI SDK v6 migration
6e53b30 
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.

Fixes anomalyco#20050
Fixes anomalyco#20465
fix: hide empty intermediate assistant messages in TUI
1b9e698 
When using the Responses API, intermediate assistant messages with
finish reason "other" were rendering empty footer bars and blank
space. Two changes:

1. Add "other" to the excluded finish reasons in final() to align
   with the prompt loop logic that treats "other" as non-terminal.

2. Add a reactive visible() memo that hides the entire
   AssistantMessage when no parts would render and no footer/error
   is shown.
@kkugot kkugot force-pushed the fix/mcp-finish-reason-20050-20465 branch from c6193db to 1b9e698 Compare April 15, 2026 09:41
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Blank assistant text with AI SDK v6: finish-reason regression when using responses api with @ai-sdk/openai

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