editor: don't include spawn agents tool call so anthropic api doesn't error

Author: jahooma

.agents/editor/best-of-n/editor-best-of-n.ts

@@ -229,6 +229,7 @@ function* handleStepsDefault({
   }
 }
 function* handleStepsMax({
+  agentState,
   params,
   logger,
 }: AgentStepContext): ReturnType<
@@ -255,6 +256,28 @@ function* handleStepsMax({
     'editor-implementor-opus',
   ] as const
 
+  // Only keep messages up to just before the last spawn agent tool call.
+  const { messageHistory: initialMessageHistory } = agentState
+  const lastSpawnAgentMessageIndex = initialMessageHistory.findLastIndex(
+    (message) =>
+      message.role === 'assistant' &&
+      Array.isArray(message.content) &&
+      message.content.length > 0 &&
+      message.content[0].type === 'tool-call' &&
+      message.content[0].toolName === 'spawn_agents',
+  )
+  const updatedMessageHistory = initialMessageHistory.slice(
+    0,
+    lastSpawnAgentMessageIndex,
+  )
+  yield {
+    toolName: 'set_messages',
+    input: {
+      messages: updatedMessageHistory,
+    },
+    includeToolCall: false,
+  } satisfies ToolCall<'set_messages'>
+
   // Spawn implementor agents using the model pattern
   const implementorAgents = MAX_MODEL_PATTERN.slice(0, n).map((agent_type) => ({
     agent_type,