diff --git a/src/agents/sandbox-agent-config.test.ts b/src/agents/sandbox-agent-config.test.ts
index ac56c97f9..1fcf0d4ed 100644
--- a/src/agents/sandbox-agent-config.test.ts
+++ b/src/agents/sandbox-agent-config.test.ts
@@ -464,7 +464,7 @@ describe("Agent-specific sandbox config", () => {
 
     expect(context).toBeDefined();
     expect(context?.tools).toEqual({
-      allow: ["read", "write"],
+      allow: ["read", "write", "image"],
       deny: ["edit"],
     });
   });
@@ -504,4 +504,30 @@ describe("Agent-specific sandbox config", () => {
     const sandbox = resolveSandboxConfigForAgent(cfg, "main");
     expect(sandbox.tools.allow).toContain("image");
   });
+
+  it("injects image into explicit sandbox allowlists", async () => {
+    const { resolveSandboxConfigForAgent } = await import("./sandbox.js");
+
+    const cfg: ClawdbotConfig = {
+      tools: {
+        sandbox: {
+          tools: {
+            allow: ["bash", "read"],
+            deny: [],
+          },
+        },
+      },
+      agents: {
+        defaults: {
+          sandbox: {
+            mode: "all",
+            scope: "agent",
+          },
+        },
+      },
+    };
+
+    const sandbox = resolveSandboxConfigForAgent(cfg, "main");
+    expect(sandbox.tools.allow).toContain("image");
+  });
 });
diff --git a/src/agents/sandbox.ts b/src/agents/sandbox.ts
index 4d9a61b60..58f1c6e60 100644
--- a/src/agents/sandbox.ts
+++ b/src/agents/sandbox.ts
@@ -475,17 +475,26 @@ export function resolveSandboxToolPolicyForAgent(
           key: "tools.sandbox.tools.deny",
         } satisfies SandboxToolPolicySource);
 
+  const deny = Array.isArray(agentDeny)
+    ? agentDeny
+    : Array.isArray(globalDeny)
+      ? globalDeny
+      : DEFAULT_TOOL_DENY;
+  let allow = Array.isArray(agentAllow)
+    ? agentAllow
+    : Array.isArray(globalAllow)
+      ? globalAllow
+      : DEFAULT_TOOL_ALLOW;
+
+  // `image` is essential for multimodal workflows; always include it in sandboxed
+  // sessions unless explicitly denied.
+  if (!deny.includes("image") && !allow.includes("image")) {
+    allow = [...allow, "image"];
+  }
+
   return {
-    allow: Array.isArray(agentAllow)
-      ? agentAllow
-      : Array.isArray(globalAllow)
-        ? globalAllow
-        : DEFAULT_TOOL_ALLOW,
-    deny: Array.isArray(agentDeny)
-      ? agentDeny
-      : Array.isArray(globalDeny)
-        ? globalDeny
-        : DEFAULT_TOOL_DENY,
+    allow,
+    deny,
     sources: {
       allow: allowSource,
       deny: denySource,