Backport: fix(google): emit no-args streaming tool calls and preserve thoughtSignature#15136
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…gnature (#14968) ## Background Vertex emits a no-args function call as a single chunk shaped `{ functionCall: { name: 'X' } }` with no `args`, no `partialArgs`, and no `willContinue`. The streaming parser in `google-language-model.ts` classifies chunks into `isStreamingChunk` / `isTerminalChunk` / `isCompleteCall`, and a no-args call matches none of them — so it falls through and is silently dropped. The unary (`doGenerate`) path has the same drop because of an `args != null` guard. For Gemini 3 thinking models that one dropped chunk also carries the response's `thoughtSignature`. Vertex enforces a multi-turn rule: an assistant turn containing any function calls must contain at least one with a `thoughtSignature`. When the dropped call is the first call (the one with the sig), the next agent step 400s with `missing thought_signature`. ## Summary - Streaming path: add a fourth classifier `isNoArgsCompleteCall` that matches `{ name: X }` with no `args` / `partialArgs` / `willContinue !== true`, and emit `tool-input-start` → `tool-input-end` → `tool-call` with `'{}'` input, propagating `providerMetadata` (so `thoughtSignature` survives). - Unary path: stop requiring `args != null`. Use `JSON.stringify(args ?? {})` so a no-args complete call from `doGenerate` is also emitted instead of dropped. ## Manual Verification See #14968 description --- Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com> Co-authored-by: Rayan Salhab <cyphercodes@users.noreply.github.com> Co-authored-by: Paul Elliot <paulelliotco@users.noreply.github.com>
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gr2m
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May 8, 2026
Fix CI failures on the backported #14968 test by: - Renaming GoogleLanguageModel → GoogleGenerativeAILanguageModel (the v6.0 class name). - Dropping the googleVertex providerMetadata key assertion. The dual-key (googleVertex + vertex) helper is a separate refactor that only exists on main; v6.0 emits a single vertex key. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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This is an automated backport of #14968 to the release-v6.0 branch. FYI @gr2m