fix(client): harden nested Tool call projection

packages/client/runtime/tests/history-fold.spec.ts

@@ -168,6 +168,37 @@ describe('projectConversationHistory', () => {
     })
   })
 
+  it('projects nested dispatches onto settled and interrupted history calls', () => {
+    const projection = projectConversationHistory([
+      ev.turnStart(0, 1),
+      ev.toolCall(1, 1, 'settled', 'run_code', '{}'),
+      ev.codeDispatchStart(2, 'settled', 1, 'run_code', { code: 'nested' }),
+      ev.codeDispatchStart(3, 'settled:code:1', 1, 'read', { path: 'a.txt' }),
+      ev.codeDispatch(4, 'settled:code:1', 1, 'read', { path: 'a.txt' }, 'alpha'),
+      ev.codeDispatch(5, 'settled', 1, 'run_code', { code: 'nested' }, 'alpha'),
+      ev.toolResult(6, 1, 'settled', 'done'),
+      ev.turnEnd(7, 1),
+      ev.turnStart(8, 2),
+      ev.toolCall(9, 2, 'interrupted', 'run_code', '{}'),
+      ev.codeDispatchStart(10, 'interrupted', 1, 'bash', { command: 'sleep 1' }),
+      ev.turnEnd(11, 2, 'aborted'),
+    ].map(event => ({ event })))
+
+    const settled = {
+      callId: 'settled',
+      subCalls: [{
+        callId: 'settled:code:1',
+        subCalls: [{ callId: 'settled:code:1:code:1', call: { name: 'read' } }],
+      }],
+    }
+    expect(projection.eventNodes).toMatchObject([settled])
+    expect(projection.contexts[0]?.nodes).toMatchObject([settled])
+    expect(projection.interruptedNodes).toMatchObject([{
+      callId: 'interrupted',
+      subCalls: [{ callId: 'interrupted:code:1', name: 'bash' }],
+    }])
+  })
+
   it('drops completed token payloads without changing inspection projections', () => {
     const events = [
       ev.user(0, 'before'),

packages/client/runtime/tests/tool-call-tree.spec.ts

@@ -0,0 +1,65 @@
+import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
+import { describe, expect, it } from 'vitest'
+import type { RunningToolCall } from '../src/client/sessions/conversation.ts'
+import { ToolCallTree } from '../src/client/sessions/tool-call-tree.ts'
+
+const at = (seq: number, type: string, data: Record<string, unknown>): SessionEvent =>
+  ({ seq, time: 1_700_000_000_000 + seq, type, data }) as unknown as SessionEvent
+
+const start = (seq: number, parentCallId: string, subCallId: string): SessionEvent =>
+  at(seq, 'tool/code-dispatch-start', {
+    parentCallId, subCallId, name: 'run_code', arguments: {},
+  })
+
+const settle = (seq: number, parentCallId: string, subCallId: string): SessionEvent =>
+  at(seq, 'tool/code-dispatch', {
+    parentCallId, subCallId, name: 'run_code', arguments: {},
+    isError: false, content: [],
+  })
+
+const root = (callId: string): RunningToolCall => ({
+  callId, name: 'run_code', argsRaw: '{}', turn: 1, step: 1,
+  time: 1_700_000_000_000, callView: null, subCalls: [],
+})
+
+describe('ToolCallTree', () => {
+  it('rejects a self-parenting dispatch edge', () => {
+    const tree = new ToolCallTree()
+    const roots = [root('root')]
+
+    expect(tree.apply(start(0, 'root', 'root'))).toBe(true)
+    expect(tree.projectRunningCalls(roots)).toBe(roots)
+  })
+
+  it('rejects a settling edge that would close a multi-call cycle', () => {
+    const tree = new ToolCallTree()
+    tree.apply(start(0, 'a', 'b'))
+    tree.apply(start(1, 'b', 'c'))
+
+    expect(tree.apply(settle(2, 'c', 'a'))).toBe(true)
+    expect(tree.projectRunningCalls([root('a')])).toMatchObject([{
+      callId: 'a',
+      subCalls: [{
+        callId: 'b',
+        subCalls: [{ callId: 'c', subCalls: [] }],
+      }],
+    }])
+  })
+
+  it('accepts an acyclic graph with a shared descendant', () => {
+    const tree = new ToolCallTree()
+    tree.apply(start(0, 'a', 'b'))
+    tree.apply(start(1, 'a', 'c'))
+    tree.apply(start(2, 'b', 'd'))
+    tree.apply(start(3, 'c', 'd'))
+
+    expect(tree.apply(start(4, 'root', 'a'))).toBe(true)
+    expect(tree.projectRunningCalls([root('root')])).toMatchObject([{
+      callId: 'root',
+      subCalls: [{
+        callId: 'a',
+        subCalls: [{ callId: 'b' }, { callId: 'c' }],
+      }],
+    }])
+  })
+})