From f0f840e6e02f65a4b56b12a2b590e8bf642a13be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E6=A9=98?= <xiaoju@shazhou.work>
Date: Fri, 22 May 2026 09:16:13 +0000
Subject: [PATCH] =?UTF-8?q?fix:=20StepOutput.sessionId=20=E2=86=92=20strin?=
 =?UTF-8?q?g=20|=20null,=20legacy=20fallback=20=E2=86=92=20null?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 packages/cli-workflow/src/commands/thread.ts | 7 +++++--
 packages/workflow-protocol/src/types.ts      | 2 +-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/packages/cli-workflow/src/commands/thread.ts b/packages/cli-workflow/src/commands/thread.ts
index b1a6c51..f695e30 100644
--- a/packages/cli-workflow/src/commands/thread.ts
+++ b/packages/cli-workflow/src/commands/thread.ts
@@ -200,6 +200,7 @@ export async function cmdThreadShow(storageRoot: string, threadId: ThreadId): Pr
       thread: threadId,
       head: activeHead,
       done: false,
+      sessionId: null,
     };
   }
 
@@ -210,6 +211,7 @@ export async function cmdThreadShow(storageRoot: string, threadId: ThreadId): Pr
       thread: threadId,
       head: hist.head,
       done: true,
+      sessionId: null,
     };
   }
 
@@ -626,7 +628,7 @@ function resolveAgentConfig(
 
 type SpawnAgentResult = {
   stepHash: CasRef;
-  sessionId: string;
+  sessionId: string | null;
 };
 
 function spawnAgent(agent: AgentConfig, threadId: ThreadId, role: string): SpawnAgentResult {
@@ -668,7 +670,7 @@ function spawnAgent(agent: AgentConfig, threadId: ThreadId, role: string): Spawn
   if (!isCasRef(line)) {
     fail(`agent stdout is not a valid CAS hash or JSON: ${line || "(empty)"}`);
   }
-  return { stepHash: line, sessionId: "" };
+  return { stepHash: line, sessionId: null };
 }
 
 async function archiveThread(
@@ -717,6 +719,7 @@ export async function cmdThreadStep(
       thread: threadId,
       head: headHash,
       done: true,
+      sessionId: null,
     };
   }
 
diff --git a/packages/workflow-protocol/src/types.ts b/packages/workflow-protocol/src/types.ts
index 01e3ec8..ec43431 100644
--- a/packages/workflow-protocol/src/types.ts
+++ b/packages/workflow-protocol/src/types.ts
@@ -81,7 +81,7 @@ export type StepOutput = {
   thread: ThreadId;
   head: CasRef;
   done: boolean;
-  sessionId?: string;
+  sessionId: string | null;
 };
 
 /** uwf thread steps — single step entry */