diff --git a/packages/builtin-tools/src/tools/TeamCreateTool/TeamCreateTool.ts b/packages/builtin-tools/src/tools/TeamCreateTool/TeamCreateTool.ts
index 3a2f8aee..138b9137 100644
--- a/packages/builtin-tools/src/tools/TeamCreateTool/TeamCreateTool.ts
+++ b/packages/builtin-tools/src/tools/TeamCreateTool/TeamCreateTool.ts
@@ -53,6 +53,8 @@ export type Output = {
   team_name: string
   team_file_path: string
   lead_agent_id: string
+  lead_agent_status: string
+  next_step: string
 }
 
 export type Input = z.infer<InputSchema>
@@ -106,7 +108,8 @@ export const TeamCreateTool: Tool<InputSchema, Output> = buildTool({
   },
 
   async description() {
-    return 'Create a new team for coordinating multiple agents'
+    return 'Create a new team with an automatically-started lead agent. ' +
+      'The lead already exists after this call — never spawn it with Agent.'
   },
 
   async prompt() {
@@ -239,6 +242,8 @@ export const TeamCreateTool: Tool<InputSchema, Output> = buildTool({
         team_name: finalTeamName,
         team_file_path: teamFilePath,
         lead_agent_id: leadAgentId,
+        lead_agent_status: `already running — created by TeamCreate, do not spawn`,
+        next_step: `SendMessage(to: "${leadAgentId}"). Use Agent only for additional teammates.`,
       },
     }
   },
diff --git a/packages/builtin-tools/src/tools/TeamCreateTool/prompt.ts b/packages/builtin-tools/src/tools/TeamCreateTool/prompt.ts
index dddf6fb1..523cc281 100644
--- a/packages/builtin-tools/src/tools/TeamCreateTool/prompt.ts
+++ b/packages/builtin-tools/src/tools/TeamCreateTool/prompt.ts
@@ -38,12 +38,24 @@ This creates:
 
 1. **Create a team** with TeamCreate - this creates both the team and its task list
 2. **Create tasks** using the Task tools (TaskCreate, TaskList, etc.) - they automatically use the team's task list
-3. **Spawn teammates** using the Agent tool with \`team_name\` and \`name\` parameters to create teammates that join the team
+3. **Spawn teammates** (beyond the lead) using the Agent tool with \`team_name\` and \`name\` parameters — but only when the task genuinely needs more than one agent. **TeamCreate already creates the lead (\`team-lead@<team_name>\`)** — do NOT pass \`name: "team-lead"\` to the Agent tool; that creates a duplicate agent, not the lead. Talk to the lead with SendMessage using the returned lead_agent_id.
 4. **Assign tasks** using TaskUpdate with \`owner\` to give tasks to idle teammates
 5. **Teammates work on assigned tasks** and mark them completed via TaskUpdate
 6. **Teammates go idle between turns** - after each turn, teammates automatically go idle and send a notification. IMPORTANT: Be patient with idle teammates! Don't comment on their idleness until it actually impacts your work.
 7. **Shutdown your team** - when the task is completed, gracefully shut down your teammates via SendMessage with \`message: {type: "shutdown_request"}\`.
 
+## Minimal Lifecycle (Single-Agent Task)
+
+When the task needs only one agent (not a multi-agent parallel workload), do NOT spawn additional teammates. The lead agent created by TeamCreate is sufficient:
+
+\`\`\`
+1. TeamCreate(team_name: "my-sweep")
+2. SendMessage(to: <lead_agent_id from step 1>, ...) — the lead receives and processes your instructions
+3. TeamDelete(team_name: "my-sweep")
+\`\`\`
+
+Use the Agent tool only to add teammates BEYOND the lead, and only when the task genuinely needs multiple agents working in parallel.
+
 ## Task Ownership
 
 Tasks are assigned using TaskUpdate with the \`owner\` parameter. Any agent can set or change task ownership via TaskUpdate.
diff --git a/packages/builtin-tools/src/tools/shared/spawnMultiAgent.ts b/packages/builtin-tools/src/tools/shared/spawnMultiAgent.ts
index 78d81102..6dd193da 100644
--- a/packages/builtin-tools/src/tools/shared/spawnMultiAgent.ts
+++ b/packages/builtin-tools/src/tools/shared/spawnMultiAgent.ts
@@ -279,6 +279,17 @@ export async function generateUniqueTeammateName(
 
   const existingNames = new Set(teamFile.members.map(m => m.name.toLowerCase()))
 
+  // If the caller tries to spawn "team-lead" which already exists (created by
+  // TeamCreate), fail with a redirect — silently deduping to "team-lead-2"
+  // would cascade into wrong SendMessage recipients and blocked TeamDelete.
+  if (baseName.toLowerCase() === TEAM_LEAD_NAME && existingNames.has(TEAM_LEAD_NAME)) {
+    throw new Error(
+      `"${TEAM_LEAD_NAME}" already exists in team "${teamName}" — it was created by TeamCreate. ` +
+        `Use SendMessage to communicate with the lead. ` +
+        `To add a different teammate, choose another name.`,
+    )
+  }
+
   // If the base name doesn't exist, use it as-is
   if (!existingNames.has(baseName.toLowerCase())) {
     return baseName