diff --git a/app/api/web-search/route.ts b/app/api/web-search/route.ts
index f2ff627f..3dfc75f3 100644
--- a/app/api/web-search/route.ts
+++ b/app/api/web-search/route.ts
@@ -5,18 +5,31 @@
  * Simple JSON request/response using Tavily search.
  */
 
+import { NextRequest } from 'next/server';
+import { callLLM } from '@/lib/ai/llm';
 import { searchWithTavily, formatSearchResultsAsContext } from '@/lib/web-search/tavily';
 import { resolveWebSearchApiKey } from '@/lib/server/provider-config';
 import { createLogger } from '@/lib/logger';
 import { apiError, apiSuccess } from '@/lib/server/api-response';
+import {
+  buildSearchQuery,
+  SEARCH_QUERY_REWRITE_EXCERPT_LENGTH,
+} from '@/lib/server/search-query-builder';
+import { resolveModelFromHeaders } from '@/lib/server/resolve-model';
+import type { AICallFn } from '@/lib/generation/pipeline-types';
 
 const log = createLogger('WebSearch');
 
-export async function POST(req: Request) {
+export async function POST(req: NextRequest) {
   try {
     const body = await req.json();
-    const { query, apiKey: clientApiKey } = body as {
+    const {
+      query,
+      pdfText,
+      apiKey: clientApiKey,
+    } = body as {
       query?: string;
+      pdfText?: string;
       apiKey?: string;
     };
 
@@ -33,7 +46,40 @@ export async function POST(req: Request) {
       );
     }
 
-    const result = await searchWithTavily({ query: query.trim(), apiKey });
+    // Clamp rewrite input at the route boundary; framework body limits still apply to total request size.
+    const boundedPdfText = pdfText?.slice(0, SEARCH_QUERY_REWRITE_EXCERPT_LENGTH);
+
+    let aiCall: AICallFn | undefined;
+    try {
+      const { model: languageModel } = resolveModelFromHeaders(req);
+      aiCall = async (systemPrompt, userPrompt) => {
+        const result = await callLLM(
+          {
+            model: languageModel,
+            messages: [
+              { role: 'system', content: systemPrompt },
+              { role: 'user', content: userPrompt },
+            ],
+            maxOutputTokens: 256,
+          },
+          'web-search-query-rewrite',
+        );
+        return result.text;
+      };
+    } catch (error) {
+      log.warn('Search query rewrite model unavailable, falling back to raw requirement:', error);
+    }
+
+    const searchQuery = await buildSearchQuery(query, boundedPdfText, aiCall);
+
+    log.info('Running web search API request', {
+      hasPdfContext: searchQuery.hasPdfContext,
+      rawRequirementLength: searchQuery.rawRequirementLength,
+      rewriteAttempted: searchQuery.rewriteAttempted,
+      finalQueryLength: searchQuery.finalQueryLength,
+    });
+
+    const result = await searchWithTavily({ query: searchQuery.query, apiKey });
     const context = formatSearchResultsAsContext(result);
 
     return apiSuccess({
diff --git a/app/generation-preview/page.tsx b/app/generation-preview/page.tsx
index b5380973..7be2a114 100644
--- a/app/generation-preview/page.tsx
+++ b/app/generation-preview/page.tsx
@@ -309,9 +309,10 @@ function GenerationPreviewContent() {
           wsSettings.webSearchProvidersConfig?.[wsSettings.webSearchProviderId]?.apiKey;
         const res = await fetch('/api/web-search', {
           method: 'POST',
-          headers: { 'Content-Type': 'application/json' },
+          headers: getApiHeaders(),
           body: JSON.stringify({
             query: currentSession.requirements.requirement,
+            pdfText: currentSession.pdfText || undefined,
             apiKey: wsApiKey || undefined,
           }),
           signal,
diff --git a/lib/generation/prompts/index.ts b/lib/generation/prompts/index.ts
index 8c6b2967..88371055 100644
--- a/lib/generation/prompts/index.ts
+++ b/lib/generation/prompts/index.ts
@@ -22,6 +22,7 @@ export {
 // Prompt IDs constant
 export const PROMPT_IDS = {
   REQUIREMENTS_TO_OUTLINES: 'requirements-to-outlines',
+  WEB_SEARCH_QUERY_REWRITE: 'web-search-query-rewrite',
   SLIDE_CONTENT: 'slide-content',
   QUIZ_CONTENT: 'quiz-content',
   SLIDE_ACTIONS: 'slide-actions',
diff --git a/lib/generation/prompts/templates/web-search-query-rewrite/system.md b/lib/generation/prompts/templates/web-search-query-rewrite/system.md
new file mode 100644
index 00000000..3d5b6a87
--- /dev/null
+++ b/lib/generation/prompts/templates/web-search-query-rewrite/system.md
@@ -0,0 +1,21 @@
+# Web Search Query Rewriter
+
+You rewrite user requests into concise, high-signal web search queries as JSON.
+
+{{snippet:json-output-rules}}
+
+## Rules
+
+- Return a JSON object with exactly one field: `query`
+- Preserve the user's intent
+- If a PDF excerpt is provided, use it to infer the topic, title, authors, methods, keywords, or named entities when helpful
+- Ignore boilerplate, copyright text, page numbers, and irrelevant noise
+- Prefer concrete topic terms over vague references like "this paper" or "this document"
+- Keep the query under 320 characters
+- If the original requirement is already concise and specific, keep it close to the original
+- If the PDF excerpt is unhelpful, rely on the requirement
+
+## Output Format
+
+Example output:
+{ "query": "your concise web search query" }
diff --git a/lib/generation/prompts/templates/web-search-query-rewrite/user.md b/lib/generation/prompts/templates/web-search-query-rewrite/user.md
new file mode 100644
index 00000000..d52f8185
--- /dev/null
+++ b/lib/generation/prompts/templates/web-search-query-rewrite/user.md
@@ -0,0 +1,14 @@
+## User Requirement
+
+{{requirement}}
+
+## PDF Excerpt
+
+{{pdfExcerpt}}
+
+## Task
+
+Write the single best web search query as a JSON object with a `query` field only.
+
+Output JSON directly (no explanation, no code fences).
+Example: {"query":"Attention Is All You Need transformer Vaswani 2017"}
diff --git a/lib/generation/prompts/types.ts b/lib/generation/prompts/types.ts
index 6df91b3f..73f0f260 100644
--- a/lib/generation/prompts/types.ts
+++ b/lib/generation/prompts/types.ts
@@ -7,6 +7,7 @@
  */
 export type PromptId =
   | 'requirements-to-outlines'
+  | 'web-search-query-rewrite'
   | 'slide-content'
   | 'quiz-content'
   | 'slide-actions'
diff --git a/lib/server/classroom-generation.ts b/lib/server/classroom-generation.ts
index eda67b4c..dc5918cd 100644
--- a/lib/server/classroom-generation.ts
+++ b/lib/server/classroom-generation.ts
@@ -19,6 +19,7 @@ import { createLogger } from '@/lib/logger';
 import { parseModelString } from '@/lib/ai/providers';
 import { resolveApiKey, resolveWebSearchApiKey } from '@/lib/server/provider-config';
 import { resolveModel } from '@/lib/server/resolve-model';
+import { buildSearchQuery } from '@/lib/server/search-query-builder';
 import { searchWithTavily, formatSearchResultsAsContext } from '@/lib/web-search/tavily';
 import { persistClassroom } from '@/lib/server/classroom-storage';
 import {
@@ -203,6 +204,21 @@ export async function generateClassroom(
     return result.text;
   };
 
+  const searchQueryAiCall: AICallFn = async (systemPrompt, userPrompt, _images) => {
+    const result = await callLLM(
+      {
+        model: languageModel,
+        messages: [
+          { role: 'system', content: systemPrompt },
+          { role: 'user', content: userPrompt },
+        ],
+        maxOutputTokens: 256,
+      },
+      'web-search-query-rewrite',
+    );
+    return result.text;
+  };
+
   const lang = normalizeLanguage(input.language);
   const requirements: UserRequirements = {
     requirement,
@@ -240,8 +256,19 @@ export async function generateClassroom(
     const tavilyKey = resolveWebSearchApiKey();
     if (tavilyKey) {
       try {
-        log.info('Running web search for requirement context...');
-        const searchResult = await searchWithTavily({ query: requirement, apiKey: tavilyKey });
+        const searchQuery = await buildSearchQuery(requirement, pdfText, searchQueryAiCall);
+
+        log.info('Running web search for classroom generation', {
+          hasPdfContext: searchQuery.hasPdfContext,
+          rawRequirementLength: searchQuery.rawRequirementLength,
+          rewriteAttempted: searchQuery.rewriteAttempted,
+          finalQueryLength: searchQuery.finalQueryLength,
+        });
+
+        const searchResult = await searchWithTavily({
+          query: searchQuery.query,
+          apiKey: tavilyKey,
+        });
         researchContext = formatSearchResultsAsContext(searchResult);
         if (researchContext) {
           log.info(`Web search returned ${searchResult.sources.length} sources`);
diff --git a/lib/server/search-query-builder.ts b/lib/server/search-query-builder.ts
new file mode 100644
index 00000000..4611c99c
--- /dev/null
+++ b/lib/server/search-query-builder.ts
@@ -0,0 +1,99 @@
+import { parseJsonResponse } from '@/lib/generation/json-repair';
+import { PROMPT_IDS, buildPrompt } from '@/lib/generation/prompts';
+import type { AICallFn } from '@/lib/generation/pipeline-types';
+import { createLogger } from '@/lib/logger';
+
+const log = createLogger('SearchQueryBuilder');
+const TAVILY_SOFT_MAX_QUERY_LENGTH = 350;
+export const SEARCH_QUERY_REWRITE_EXCERPT_LENGTH = 7000;
+
+interface SearchQueryRewriteResponse {
+  query: string;
+}
+
+export interface SearchQueryBuildResult {
+  query: string;
+  rewriteAttempted: boolean;
+  rawRequirementLength: number;
+  finalQueryLength: number;
+  hasPdfContext: boolean;
+}
+
+function normalizeSearchRequirement(requirement: string): string {
+  return requirement.replace(/\s+/g, ' ').trim();
+}
+
+function normalizePdfExcerpt(pdfText?: string): string {
+  if (!pdfText) {
+    return '';
+  }
+
+  return pdfText.replace(/\s+/g, ' ').trim().slice(0, SEARCH_QUERY_REWRITE_EXCERPT_LENGTH);
+}
+
+function shouldRewriteSearchQuery(
+  normalizedRequirement: string,
+  normalizedPdfExcerpt: string,
+): boolean {
+  return normalizedRequirement.length > 400 || Boolean(normalizedPdfExcerpt);
+}
+
+export async function buildSearchQuery(
+  requirement: string,
+  pdfText: string | undefined,
+  aiCall?: AICallFn,
+): Promise<SearchQueryBuildResult> {
+  const normalizedRequirement = normalizeSearchRequirement(requirement);
+  const pdfExcerpt = normalizePdfExcerpt(pdfText);
+  const hasPdfContext = Boolean(pdfExcerpt);
+  const rewriteAttempted = shouldRewriteSearchQuery(normalizedRequirement, pdfExcerpt);
+
+  const fallback = {
+    query: normalizedRequirement,
+    rewriteAttempted,
+    rawRequirementLength: normalizedRequirement.length,
+    finalQueryLength: normalizedRequirement.length,
+    hasPdfContext,
+  } satisfies SearchQueryBuildResult;
+
+  if (!normalizedRequirement || !rewriteAttempted) {
+    return fallback;
+  }
+
+  if (!aiCall) {
+    log.warn('Query rewrite AI call unavailable, falling back to raw requirement');
+    return fallback;
+  }
+
+  const prompts = buildPrompt(PROMPT_IDS.WEB_SEARCH_QUERY_REWRITE, {
+    requirement: normalizedRequirement,
+    pdfExcerpt: pdfExcerpt || 'None',
+  });
+
+  if (!prompts) {
+    log.warn('Query rewrite prompt not found, falling back to raw requirement');
+    return fallback;
+  }
+
+  try {
+    const response = await aiCall(prompts.system, prompts.user);
+    const parsed = parseJsonResponse<SearchQueryRewriteResponse>(response);
+    const rewrittenQuery = normalizeSearchRequirement(parsed?.query || '').slice(
+      0,
+      TAVILY_SOFT_MAX_QUERY_LENGTH,
+    );
+    if (!rewrittenQuery) {
+      log.warn('Query rewrite returned empty output, falling back to raw requirement');
+      return fallback;
+    }
+
+    return {
+      ...fallback,
+      query: rewrittenQuery,
+      finalQueryLength: rewrittenQuery.length,
+    };
+  } catch (error) {
+    log.warn('Query rewrite failed, falling back to raw requirement:', error);
+    return fallback;
+  }
+}