diff --git a/CHANGELOG.md b/CHANGELOG.md
index 689718d36..8d1663411 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added per-step token cost tracking and estimated tool call token usage to Ask Sourcebot chat history. [#1353](https://github.com/sourcebot-dev/sourcebot/pull/1353)
 
 ### Fixed
+- Fixed a crash when searching with `context:` referencing a search context that does not exist; it now returns a graceful error. [#1362](https://github.com/sourcebot-dev/sourcebot/pull/1362)
 - Send anonymous server-side PostHog events as personless so unauthenticated requests don't inflate person counts. [#1367](https://github.com/sourcebot-dev/sourcebot/pull/1367)
 
 ## [5.0.4] - 2026-06-18
diff --git a/packages/web/src/features/search/parser.test.ts b/packages/web/src/features/search/parser.test.ts
new file mode 100644
index 000000000..69c4fcb47
--- /dev/null
+++ b/packages/web/src/features/search/parser.test.ts
@@ -0,0 +1,45 @@
+import { describe, expect, it } from 'vitest';
+import type { PrismaClient } from '@sourcebot/db';
+import { parseQuerySyntaxIntoIR } from './parser';
+import { ServiceErrorException } from '@/lib/serviceError';
+import { ErrorCode } from '@/lib/errorCodes';
+
+describe('parseQuerySyntaxIntoIR', () => {
+    it('throws a ServiceErrorException when a search context is not found', async () => {
+        const prisma = {
+            searchContext: {
+                findUnique: async () => null,
+            },
+        } as unknown as PrismaClient;
+
+        const promise = parseQuerySyntaxIntoIR({
+            query: 'Helpers context:0',
+            options: {},
+            prisma,
+        });
+
+        await expect(promise).rejects.toBeInstanceOf(ServiceErrorException);
+        await expect(promise).rejects.toMatchObject({
+            serviceError: { errorCode: ErrorCode.SEARCH_CONTEXT_NOT_FOUND },
+        });
+    });
+
+    it('expands a search context into its repo set when found', async () => {
+        const prisma = {
+            searchContext: {
+                findUnique: async () => ({
+                    repos: [{ name: 'org/repo-a' }, { name: 'org/repo-b' }],
+                }),
+            },
+        } as unknown as PrismaClient;
+
+        const ir = await parseQuerySyntaxIntoIR({
+            query: 'context:my-context',
+            options: {},
+            prisma,
+        });
+
+        expect(JSON.stringify(ir)).toContain('org/repo-a');
+        expect(JSON.stringify(ir)).toContain('org/repo-b');
+    });
+});
diff --git a/packages/web/src/features/search/parser.ts b/packages/web/src/features/search/parser.ts
index 3b188a825..bb3ee5d77 100644
--- a/packages/web/src/features/search/parser.ts
+++ b/packages/web/src/features/search/parser.ts
@@ -114,7 +114,11 @@ export const parseQuerySyntaxIntoIR = async ({
                 });
 
                 if (!context) {
-                    throw new Error(`Search context "${contextName}" not found`);
+                    throw new ServiceErrorException({
+                        statusCode: StatusCodes.NOT_FOUND,
+                        errorCode: ErrorCode.SEARCH_CONTEXT_NOT_FOUND,
+                        message: `Search context "${contextName}" not found`,
+                    });
                 }
 
                 return context.repos.map((repo) => repo.name);