diff --git a/apps/server/src/provider/Layers/ClaudeAdapter.ts b/apps/server/src/provider/Layers/ClaudeAdapter.ts
index 2fd40f6ecc5..556504d6cf4 100644
--- a/apps/server/src/provider/Layers/ClaudeAdapter.ts
+++ b/apps/server/src/provider/Layers/ClaudeAdapter.ts
@@ -2873,6 +2873,7 @@ export const makeClaudeAdapter = Effect.fn("makeClaudeAdapter")(function* (
         ...(input.cwd ? { cwd: input.cwd } : {}),
         ...(apiModelId ? { model: apiModelId } : {}),
         pathToClaudeCodeExecutable: claudeBinaryPath,
+        systemPrompt: { type: "preset", preset: "claude_code" },
         settingSources: [...CLAUDE_SETTING_SOURCES],
         // The SDK type lags the CLI here: Opus 4.7 accepts `xhigh` even though
         // the published `Options["effort"]` union currently stops at `max`.