feat: use native Output.object() for structured output#18450
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potlee wants to merge 2 commits intoanomalyco:devfrom
Open
feat: use native Output.object() for structured output#18450potlee wants to merge 2 commits intoanomalyco:devfrom
potlee wants to merge 2 commits intoanomalyco:devfrom
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…ool-based approach Use the AI SDK's experimental_output with Output.object() to leverage providers' native JSON mode (response_format) instead of a synthetic StructuredOutput tool with forced toolChoice.
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Issue for this PR
Closes #
Type of change
What does this PR do?
Switches structured output from a custom
StructuredOutputtool to the AI SDK's nativeOutput.object()viaexperimental_output.Previously, when
format.type === "json_schema"was set, the code would:StructuredOutputtooltoolChoice: "required"so the model had to call itThis was fragile — it consumed a tool slot, required prompt engineering to make the model cooperate, and bypassed the provider's native JSON mode support.
Now it passes
experimental_output: Output.object({ schema })tostreamText(), which setsresponseFormat: { type: "json", schema }on the underlying provider call. Providers that support native JSON schema will use their built-in mechanisms, AI SDK handles the fallback to using a tool when structured output is not supported. The model outputs JSON text directly, the processor parses it, and tools still work alongside structured output for multi-step workflows.Net removal of ~300 lines of tool scaffolding, system prompt injection, and manual plumbing.
How did you verify your code works?
bun typecheckpasses with 0 errors (frompackages/opencode)bun test test/session/structured-output.test.ts— 13 pass, 0 failbun test test/session/structured-output-integration.test.ts— 1 pass, 4 skipped (require API key), 0 failScreenshots / recordings
N/A — no UI changes.
Checklist