fix: preserve reasoning metadata across model switches

chan1103 · chan1103 · commit ae203092444f · 2026-04-14T13:10:25.000+09:00
The differentModel guard strips providerMetadata from all parts when the
current model differs from the stored message model. For reasoning parts
this removes thinking block signatures, causing Anthropic to reject the
history. Reasoning parts now always preserve their metadata since it is
provider-scoped and harmless to other providers.
diff --git a/packages/opencode/src/session/message-v2.ts b/packages/opencode/src/session/message-v2.ts
@@ -795,7 +795,7 @@ export namespace MessageV2 {
             assistantMessage.parts.push({
               type: "reasoning",
               text: part.text,
-              ...(differentModel ? {} : { providerMetadata: part.metadata }),
+              providerMetadata: part.metadata,
             })
           }
         }

Original file line number	Diff line number	Diff line change
`@@ -795,7 +795,7 @@ export namespace MessageV2 {`
`795`	`795`	`assistantMessage.parts.push({`
`796`	`796`	`type: "reasoning",`
`797`	`797`	`text: part.text,`
`798`		`- ...(differentModel ? {} : { providerMetadata: part.metadata }),`
	`798`	`+ providerMetadata: part.metadata,`
`799`	`799`	`})`
`800`	`800`	`}`
`801`	`801`	`}`