feat(wiki-compose): add Japanese UI and localized LLM output

server/api/src/__tests__/agents/core/composeLocale.test.ts

@@ -0,0 +1,41 @@
+import { describe, expect, it } from "vitest";
+import {
+  composeConflictRationale,
+  composeContentLocaleInstruction,
+  normalizeComposeContentLocale,
+  resolveComposeContentLocale,
+  stripContentLocaleFromGraphInput,
+  structureDialogueFallbackOutline,
+} from "../../../agents/core/composeLocale.js";
+
+describe("composeLocale", () => {
+  it("normalizes supported locales only", () => {
+    expect(normalizeComposeContentLocale("ja")).toBe("ja");
+    expect(normalizeComposeContentLocale("en")).toBe("en");
+    expect(normalizeComposeContentLocale("fr")).toBeNull();
+  });
+
+  it("resolves from input then Accept-Language", () => {
+    expect(resolveComposeContentLocale({ contentLocale: "en" }, "ja-JP")).toBe("en");
+    expect(resolveComposeContentLocale({}, "ja-JP,en;q=0.8")).toBe("ja");
+    expect(resolveComposeContentLocale({}, "en-US,en;q=0.9")).toBe("en");
+    expect(resolveComposeContentLocale({}, null, "ja")).toBe("ja");
+  });
+
+  it("strips contentLocale from graph input", () => {
+    expect(stripContentLocaleFromGraphInput({ contentLocale: "ja", chatSeed: { x: 1 } })).toEqual({
+      chatSeed: { x: 1 },
+    });
+  });
+
+  it("includes Japanese in locale instruction when ja", () => {
+    expect(composeContentLocaleInstruction("ja")).toMatch(/Japanese/);
+    expect(composeContentLocaleInstruction("en")).toMatch(/English/);
+  });
+
+  it("provides localized conflict rationale and fallback outline", () => {
+    expect(composeConflictRationale("ja")).toMatch(/却下/);
+    expect(structureDialogueFallbackOutline("ja")[0]?.heading).toBe("概要");
+    expect(structureDialogueFallbackOutline("en")[0]?.heading).toBe("Overview");
+  });
+});

server/api/src/agents/core/composeLocale.ts

@@ -0,0 +1,102 @@
+/**
+ * Content locale for Wiki Compose LLM outputs (#950).
+ * Wiki Compose の生成言語（ユーザー向けテキスト）を表す。
+ */
+export type ComposeContentLocale = "ja" | "en";
+
+/**
+ * Normalize an arbitrary value to a supported compose content locale.
+ * 任意の入力をサポートされる compose 用ロケールに正規化する。
+ */
+export function normalizeComposeContentLocale(raw: unknown): ComposeContentLocale | null {
+  if (raw === "ja" || raw === "en") return raw;
+  return null;
+}
+
+/**
+ * Resolve locale from graph run input (`contentLocale`) with a server default.
+ * graph の run input（`contentLocale`）からロケールを解決する。
+ */
+export function resolveComposeContentLocale(
+  input: unknown,
+  acceptLanguage: string | undefined | null,
+  fallback: ComposeContentLocale = "ja",
+): ComposeContentLocale {
+  if (input && typeof input === "object" && "contentLocale" in input) {
+    const fromInput = normalizeComposeContentLocale(
+      (input as { contentLocale?: unknown }).contentLocale,
+    );
+    if (fromInput) return fromInput;
+  }
+  if (acceptLanguage) {
+    const primary = acceptLanguage.split(",")[0]?.trim().toLowerCase() ?? "";
+    if (primary.startsWith("ja")) return "ja";
+    if (primary.startsWith("en")) return "en";
+  }
+  return fallback;
+}
+
+/**
+ * Strip `contentLocale` before passing input to LangGraph (not a state channel).
+ * LangGraph に渡す前に `contentLocale` を除去する（state チャネルではない）。
+ */
+export function stripContentLocaleFromGraphInput(raw: unknown): unknown {
+  if (!raw || typeof raw !== "object" || Array.isArray(raw)) return raw ?? {};
+  const { contentLocale: _removed, ...rest } = raw as Record<string, unknown>;
+  return rest;
+}
+
+/**
+ * Instruction appended to system prompts so questions, outlines, and drafts
+ * match the user's UI language.
+ * 質問・アウトライン・本文が UI 言語と一致するよう system prompt に付与する。
+ */
+export function composeContentLocaleInstruction(locale: ComposeContentLocale): string {
+  if (locale === "ja") {
+    return (
+      "\n\nLanguage: Write all user-facing text (questions, option labels, rationales, " +
+      "outline headings and intents, evaluation rationales, missing aspects, and article " +
+      "body) in Japanese. Use clear, natural Japanese suitable for a wiki article."
+    );
+  }
+  return (
+    "\n\nLanguage: Write all user-facing text (questions, option labels, rationales, " +
+    "outline headings and intents, evaluation rationales, missing aspects, and article " +
+    "body) in English."
+  );
+}
+
+/**
+ * Localized conflict-resolution rationale shown in the interrupt UI.
+ * interrupt UI に表示する矛盾解消用の説明文（ロケール別）。
+ */
+export function composeConflictRationale(locale: ComposeContentLocale): string {
+  if (locale === "ja") {
+    return (
+      "却下したソースと採用したソースが混在しています。採用したソースのセットで" +
+      "アウトライン生成に進んでよいか確認してください。"
+    );
+  }
+  return (
+    "Multiple sources were rejected while others were kept. Confirm you want to proceed " +
+    "with the approved set before generating the outline."
+  );
+}
+
+/** Default outline rows when structure LLM fails (locale-specific headings). */
+export function structureDialogueFallbackOutline(
+  locale: ComposeContentLocale,
+): Array<{ heading: string; depth: 1; intent: string }> {
+  if (locale === "ja") {
+    return [
+      { heading: "概要", depth: 1, intent: "トピックの簡潔な導入。" },
+      { heading: "要点", depth: 1, intent: "主要な事実と背景。" },
+      { heading: "参考", depth: 1, intent: "出典と関連情報。" },
+    ];
+  }
+  return [
+    { heading: "Overview", depth: 1, intent: "Brief introduction to the topic." },
+    { heading: "Key points", depth: 1, intent: "Main facts and context." },
+    { heading: "References", depth: 1, intent: "Sources and further reading." },
+  ];
+}

server/api/src/agents/core/types/graphContext.ts

@@ -10,6 +10,7 @@
  * identifiers required by `ZediChatModel` for usage attribution.
  */
 import type { Database, UserTier } from "../../../types/index.js";
+import type { ComposeContentLocale } from "../composeLocale.js";
 import type { ExecutionBackend } from "./executionBackend.js";
 
 /**
@@ -31,6 +32,8 @@ import type { ExecutionBackend } from "./executionBackend.js";
  *                     Executing user's email; used by `wikiSearchService` to
  *                     apply the `note_domain_access` predicate without an
  *                     extra DB roundtrip per tool call.
+ * @property contentLocale 生成テキストの言語（`ja` | `en`）。UI / Accept-Language から解決。
+ *                     Language for LLM-generated user-facing text (`ja` | `en`).
  */
 export interface GraphContext {
   threadId: string;
@@ -43,6 +46,7 @@ export interface GraphContext {
   db: Database;
   feature: string;
   userEmail: string | null;
+  contentLocale: ComposeContentLocale;
 }
 
 /**

server/api/src/agents/graphs/wikiCompose/nodes/briefDialogue.ts

@@ -14,6 +14,7 @@
 import type { LangGraphRunnableConfig } from "@langchain/langgraph";
 import { randomUUID } from "node:crypto";
 import { z } from "zod";
+import { composeContentLocaleInstruction } from "../../../core/composeLocale.js";
 import { createZediChatModel } from "../../../core/llm/modelFactory.js";
 import { resolveComposeModelId } from "../../../core/llm/resolveComposeModelId.js";
 import { getGraphContext } from "../../../subgraphs/research/nodes/shared/getGraphContext.js";
@@ -135,7 +136,10 @@ export async function briefDialogue(
   let briefDegraded = false;
   try {
     raw = await structured.invoke([
-      { role: "system", content: SYSTEM_PROMPT },
+      {
+        role: "system",
+        content: SYSTEM_PROMPT + composeContentLocaleInstruction(ctx.contentLocale),
+      },
       {
         role: "user",
         content: buildUserPrompt(snapshot.title, snapshot.body, state.chatSeed),

server/api/src/agents/graphs/wikiCompose/nodes/conflictResolution.ts

@@ -8,18 +8,24 @@
  */
 import type { LangGraphRunnableConfig } from "@langchain/langgraph";
 import { interrupt } from "@langchain/langgraph";
+import {
+  composeConflictRationale,
+  type ComposeContentLocale,
+} from "../../../core/composeLocale.js";
+import { getGraphContext } from "../../../subgraphs/research/nodes/shared/getGraphContext.js";
 import { conflictResumeSchema } from "../resumeSchemas.js";
 import type { WikiComposeStateType, WikiComposeStateUpdate } from "../state.js";
 import type { ResearchConflictSummary, WikiComposeInterruptPayload } from "../types.js";
 import { shouldResolveResearchConflicts } from "../routing.js";
 
-function buildConflictSummary(state: WikiComposeStateType): ResearchConflictSummary {
+function buildConflictSummary(
+  state: WikiComposeStateType,
+  locale: ComposeContentLocale,
+): ResearchConflictSummary {
   return {
     approved: state.approvedResearch.map((s) => ({ id: s.id, title: s.title })),
     rejected: state.rejectedResearch.map((s) => ({ id: s.id, title: s.title })),
-    rationale:
-      "Multiple sources were rejected while others were kept. Confirm you want to proceed " +
-      "with the approved set before generating the outline.",
+    rationale: composeConflictRationale(locale),
   };
 }
 
@@ -29,15 +35,16 @@ function buildConflictSummary(state: WikiComposeStateType): ResearchConflictSumm
  */
 export async function conflictResolution(
   state: WikiComposeStateType,
-  _config: LangGraphRunnableConfig,
+  config: LangGraphRunnableConfig,
 ): Promise<WikiComposeStateUpdate> {
   if (!shouldResolveResearchConflicts(state)) {
     return { phase: "conflict:skipped" };
   }
 
+  const ctx = getGraphContext(config);
   const payload: WikiComposeInterruptPayload = {
     kind: "conflict_resolution",
-    conflicts: buildConflictSummary(state),
+    conflicts: buildConflictSummary(state, ctx.contentLocale),
   };
   const resumeValue: unknown = interrupt(payload);
   conflictResumeSchema.parse(resumeValue);

server/api/src/agents/graphs/wikiCompose/nodes/draftSections.ts

@@ -13,6 +13,7 @@
  * paint into the EditorPane.
  */
 import type { LangGraphRunnableConfig } from "@langchain/langgraph";
+import { composeContentLocaleInstruction } from "../../../core/composeLocale.js";
 import { createZediChatModel } from "../../../core/llm/modelFactory.js";
 import { resolveComposeModelId } from "../../../core/llm/resolveComposeModelId.js";
 import { getGraphContext } from "../../../subgraphs/research/nodes/shared/getGraphContext.js";
@@ -158,7 +159,10 @@ export async function draftSections(
     let body = "";
     try {
       const stream = await model.stream([
-        { role: "system", content: SECTION_SYSTEM_PROMPT },
+        {
+          role: "system",
+          content: SECTION_SYSTEM_PROMPT + composeContentLocaleInstruction(ctx.contentLocale),
+        },
         {
           role: "user",
           content: buildSectionPrompt({

server/api/src/agents/graphs/wikiCompose/nodes/structureDialogue.ts

@@ -14,6 +14,10 @@
 import type { LangGraphRunnableConfig } from "@langchain/langgraph";
 import { randomUUID } from "node:crypto";
 import { z } from "zod";
+import {
+  composeContentLocaleInstruction,
+  structureDialogueFallbackOutline,
+} from "../../../core/composeLocale.js";
 import { createZediChatModel } from "../../../core/llm/modelFactory.js";
 import { resolveComposeModelId } from "../../../core/llm/resolveComposeModelId.js";
 import { getGraphContext } from "../../../subgraphs/research/nodes/shared/getGraphContext.js";
@@ -99,21 +103,18 @@ export async function structureDialogue(
   let raw: z.input<typeof outlineProposalSchema>;
   try {
     raw = await structured.invoke([
-      { role: "system", content: SYSTEM_PROMPT },
+      {
+        role: "system",
+        content: SYSTEM_PROMPT + composeContentLocaleInstruction(ctx.contentLocale),
+      },
       { role: "user", content: buildUserPrompt(state) },
     ]);
   } catch {
     // Defensive fallback: emit a minimal 3-section outline so the user can
     // edit-rather-than-blank-out when the LLM fails (rare). Heading text
     // intentionally generic so the user is prompted to rename.
     // LLM 失敗時は 3 セクションの仮アウトラインを返してフローを止めない。
-    raw = {
-      sections: [
-        { heading: "Overview", depth: 1, intent: "Brief introduction to the topic." },
-        { heading: "Key points", depth: 1, intent: "Main facts and context." },
-        { heading: "References", depth: 1, intent: "Sources and further reading." },
-      ],
-    };
+    raw = { sections: structureDialogueFallbackOutline(ctx.contentLocale) };
   }
 
   const outline: OutlineSection[] = raw.sections.map((s) => ({

server/api/src/agents/subgraphs/research/nodes/evaluateSufficiency.ts

@@ -10,6 +10,7 @@
  */
 import type { LangGraphRunnableConfig } from "@langchain/langgraph";
 import { z } from "zod";
+import { composeContentLocaleInstruction } from "../../../core/composeLocale.js";
 import { createZediChatModel } from "../../../core/llm/modelFactory.js";
 import { resolveComposeModelId } from "../../../core/llm/resolveComposeModelId.js";
 import { getGraphContext } from "./shared/getGraphContext.js";
@@ -88,7 +89,10 @@ export async function evaluateSufficiency(
     name: "research_evaluation",
   });
   const parsed = await structured.invoke([
-    { role: "system", content: SYSTEM_PROMPT },
+    {
+      role: "system",
+      content: SYSTEM_PROMPT + composeContentLocaleInstruction(ctx.contentLocale),
+    },
     { role: "user", content: buildUserPrompt(state) },
   ]);
   const evaluation: Evaluation = {

server/api/src/agents/subgraphs/research/nodes/planQueries.ts

@@ -14,6 +14,7 @@
 import type { LangGraphRunnableConfig } from "@langchain/langgraph";
 import { randomUUID } from "node:crypto";
 import { z } from "zod";
+import { composeContentLocaleInstruction } from "../../../core/composeLocale.js";
 import { createZediChatModel } from "../../../core/llm/modelFactory.js";
 import { resolveComposeModelId } from "../../../core/llm/resolveComposeModelId.js";
 import { getGraphContext } from "./shared/getGraphContext.js";
@@ -112,7 +113,10 @@ export async function planQueries(
   });
   const structured = model.withStructuredOutput(planQueriesSchema, { name: "plan_queries" });
   const planned = await structured.invoke([
-    { role: "system", content: SYSTEM_PROMPT },
+    {
+      role: "system",
+      content: SYSTEM_PROMPT + composeContentLocaleInstruction(ctx.contentLocale),
+    },
     { role: "user", content: brief || "(no brief provided; produce 2 broad coverage queries)" },
   ]);
 

server/api/src/agents/subgraphs/research/nodes/refineQueries.ts

@@ -8,6 +8,7 @@
  */
 import type { LangGraphRunnableConfig } from "@langchain/langgraph";
 import { randomUUID } from "node:crypto";
+import { composeContentLocaleInstruction } from "../../../core/composeLocale.js";
 import { createZediChatModel } from "../../../core/llm/modelFactory.js";
 import { resolveComposeModelId } from "../../../core/llm/resolveComposeModelId.js";
 import { getGraphContext } from "./shared/getGraphContext.js";
@@ -74,7 +75,10 @@ export async function refineQueries(
   });
   const structured = model.withStructuredOutput(planQueriesSchema, { name: "refine_queries" });
   const planned = await structured.invoke([
-    { role: "system", content: SYSTEM_PROMPT },
+    {
+      role: "system",
+      content: SYSTEM_PROMPT + composeContentLocaleInstruction(ctx.contentLocale),
+    },
     { role: "user", content: buildUserPrompt(state) },
   ]);
   const queries: PlannedQuery[] = planned.queries.map((q) => ({

server/api/src/agents/subgraphs/research/nodes/shared/getGraphContext.ts

@@ -8,6 +8,7 @@
  * で誤って忘れたケースを早期に検出するため throw する。
  */
 import type { LangGraphRunnableConfig } from "@langchain/langgraph";
+import { normalizeComposeContentLocale } from "../../../../core/composeLocale.js";
 import {
   GRAPH_CONTEXT_CONFIG_KEY,
   type GraphContext,
@@ -44,5 +45,9 @@ export function getGraphContext(config: LangGraphRunnableConfig | undefined): Gr
         "Check GraphRunner.buildConfig.",
     );
   }
-  return ctx as GraphContext;
+  const contentLocale =
+    normalizeComposeContentLocale(ctx.contentLocale) ??
+    normalizeComposeContentLocale((ctx as { locale?: unknown }).locale) ??
+    "en";
+  return { ...(ctx as GraphContext), contentLocale };
 }