From 32dfe1b6b012e40be77aaf34243088354d6a63da Mon Sep 17 00:00:00 2001
From: Robin1987China <41602358+Robin1987China@users.noreply.github.com>
Date: Mon, 22 Jun 2026 16:55:39 +0800
Subject: [PATCH] fix(llm): forward frequencyPenalty, presencePenalty, seed to
 Gemini

GenerationOptions defines frequencyPenalty, presencePenalty, and seed as
user-settable generation parameters, and the OpenAI-chat protocol forwards
all three. The Gemini protocol dropped them: GeminiGenerationConfig only
declared maxOutputTokens/temperature/topP/topK/stopSequences/thinkingConfig
and the request builder forwarded only those.

Gemini's generateContent generationConfig supports all three, so values a
user sets were honored on OpenAI but silently ignored on Gemini. Add the
three fields to the schema and forward them, gated by the existing
all-undefined guard so unset requests are unchanged.

Closes #33325
---
 packages/llm/src/protocols/gemini.ts      |  6 ++++++
 packages/llm/test/provider/gemini.test.ts | 18 ++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/packages/llm/src/protocols/gemini.ts b/packages/llm/src/protocols/gemini.ts
index c8fa34b50965..53dd84ae8d39 100644
--- a/packages/llm/src/protocols/gemini.ts
+++ b/packages/llm/src/protocols/gemini.ts
@@ -99,6 +99,9 @@ const GeminiGenerationConfig = Schema.Struct({
   temperature: Schema.optional(Schema.Number),
   topP: Schema.optional(Schema.Number),
   topK: Schema.optional(Schema.Number),
+  frequencyPenalty: Schema.optional(Schema.Number),
+  presencePenalty: Schema.optional(Schema.Number),
+  seed: Schema.optional(Schema.Number),
   stopSequences: optionalArray(Schema.String),
   thinkingConfig: Schema.optional(GeminiThinkingConfig),
 })
@@ -305,6 +308,9 @@ const fromRequest = Effect.fn("Gemini.fromRequest")(function* (request: LLMReque
     temperature: generation?.temperature,
     topP: generation?.topP,
     topK: generation?.topK,
+    frequencyPenalty: generation?.frequencyPenalty,
+    presencePenalty: generation?.presencePenalty,
+    seed: generation?.seed,
     stopSequences: generation?.stop,
     thinkingConfig: thinkingConfig(request),
   }
diff --git a/packages/llm/test/provider/gemini.test.ts b/packages/llm/test/provider/gemini.test.ts
index d30742c47d35..a7e52c503cab 100644
--- a/packages/llm/test/provider/gemini.test.ts
+++ b/packages/llm/test/provider/gemini.test.ts
@@ -36,6 +36,24 @@ describe("Gemini route", () => {
     }),
   )
 
+  it.effect("forwards frequencyPenalty, presencePenalty, and seed to generationConfig", () =>
+    Effect.gen(function* () {
+      const prepared = yield* LLMClient.prepare<Gemini.GeminiBody>(
+        LLM.request({
+          model,
+          prompt: "Say hello.",
+          generation: { frequencyPenalty: 0.5, presencePenalty: 0.25, seed: 7 },
+        }),
+      )
+
+      expect(prepared.body.generationConfig).toMatchObject({
+        frequencyPenalty: 0.5,
+        presencePenalty: 0.25,
+        seed: 7,
+      })
+    }),
+  )
+
   it.effect("lowers chronological system updates to wrapped user text in order", () =>
     Effect.gen(function* () {
       const prepared = yield* LLMClient.prepare<Gemini.GeminiBody>(