diff --git a/packages/opencode/src/tool/task.ts b/packages/opencode/src/tool/task.ts
index 170d4448088e..d27a428cf5c6 100644
--- a/packages/opencode/src/tool/task.ts
+++ b/packages/opencode/src/tool/task.ts
@@ -61,8 +61,10 @@ export const TaskTool = Tool.define("task", async (ctx) => {
 
       const session = await iife(async () => {
         if (params.session_id) {
-          const found = await Session.get(params.session_id).catch(() => {})
-          if (found) return found
+          try {
+            const found = await Session.get(params.session_id)
+            if (found) return found
+          } catch {}
         }
 
         return await Session.create({
diff --git a/packages/opencode/test/tool/task.test.ts b/packages/opencode/test/tool/task.test.ts
new file mode 100644
index 000000000000..7bb95b6e95bc
--- /dev/null
+++ b/packages/opencode/test/tool/task.test.ts
@@ -0,0 +1,68 @@
+import { describe, expect, test } from "bun:test"
+import path from "path"
+import { TaskTool } from "../../src/tool/task"
+import { Instance } from "../../src/project/instance"
+import { Session } from "../../src/session"
+import { Identifier } from "../../src/id/id"
+import { Tool } from "../../src/tool/tool"
+
+const projectRoot = path.join(__dirname, "../..")
+
+describe("tool.task", () => {
+  test("handles invalid session_id gracefully", async () => {
+    await Instance.provide({
+      directory: projectRoot,
+      fn: async () => {
+        const session = await Session.create({})
+        const messageID = Identifier.ascending("message")
+        
+        await Session.updateMessage({
+          id: messageID,
+          sessionID: session.id,
+          role: "assistant",
+          parentID: Identifier.ascending("message"),
+          modelID: "dummy-model",
+          providerID: "dummy-provider",
+          mode: "auto",
+          agent: "primary",
+          path: { cwd: "/", root: "/" },
+          cost: 0,
+          tokens: {
+            input: 0,
+            output: 0,
+            reasoning: 0,
+            cache: { read: 0, write: 0 }
+          },
+          time: { created: Date.now() }
+        })
+
+        const ctx: Tool.Context = {
+          sessionID: session.id,
+          messageID: messageID,
+          agent: "primary",
+          abort: AbortSignal.any([]),
+          metadata: () => {},
+          ask: async () => {},
+        }
+
+        let error: Error | undefined
+        try {
+          const task = await TaskTool.init({ agent: { name: "primary" } as any })
+          await task.execute(
+            {
+              description: "test subtask",
+              prompt: "do something",
+              subagent_type: "explore",
+              session_id: "invalid_id_format",
+            },
+            ctx,
+          )
+        } catch (e) {
+          error = e as Error
+        }
+        expect(error).toBeDefined()
+        expect(error?.message).not.toContain("Invalid string: must start with")
+      }
+    })
+  })
+})