diff --git a/src/features/team-mode/resolve-caller-team-lead.test.ts b/src/features/team-mode/resolve-caller-team-lead.test.ts
new file mode 100644
index 000000000..5500f6a17
--- /dev/null
+++ b/src/features/team-mode/resolve-caller-team-lead.test.ts
@@ -0,0 +1,160 @@
+/// <reference types="bun-types" />
+
+import { describe, expect, test } from "bun:test"
+
+import { resolveCallerTeamLead, shouldReuseCallerLeadSession } from "./resolve-caller-team-lead"
+import type { TeamSpec } from "./types"
+
+function makeSpec(overrides: Partial<TeamSpec> = {}): TeamSpec {
+  return {
+    version: 1,
+    name: "test-team",
+    createdAt: Date.now(),
+    leadAgentId: "lead",
+    members: [
+      { kind: "subagent_type", name: "lead", subagent_type: "sisyphus", backendType: "in-process", isActive: true },
+      { kind: "category", name: "worker", category: "quick", prompt: "do work", backendType: "in-process", isActive: true },
+    ],
+    ...overrides,
+  }
+}
+
+describe("resolveCallerTeamLead", () => {
+  test("returns an eligible sisyphus lead for the plain display name", () => {
+    // given
+    const rawAgentName = "Sisyphus"
+
+    // when
+    const result = resolveCallerTeamLead(rawAgentName)
+
+    // then
+    expect(result).toEqual({
+      agentTypeId: "sisyphus",
+      displayName: "Sisyphus",
+      isEligibleForTeamLead: true,
+    })
+  })
+
+  test("returns an eligible sisyphus lead for the suffixed display name", () => {
+    // given
+    const rawAgentName = "Sisyphus - Ultraworker"
+
+    // when
+    const result = resolveCallerTeamLead(rawAgentName)
+
+    // then
+    expect(result).toEqual({
+      agentTypeId: "sisyphus",
+      displayName: "Sisyphus - Ultraworker",
+      isEligibleForTeamLead: true,
+    })
+  })
+
+  test("strips visible ordering prefixes before resolving the caller lead", () => {
+    // given
+    const rawAgentName = "00|Sisyphus"
+
+    // when
+    const result = resolveCallerTeamLead(rawAgentName)
+
+    // then
+    expect(result).toEqual({
+      agentTypeId: "sisyphus",
+      displayName: "Sisyphus",
+      isEligibleForTeamLead: true,
+    })
+  })
+
+  test("returns not eligible when the caller agent is undefined", () => {
+    // given
+    const rawAgentName = undefined
+
+    // when
+    const result = resolveCallerTeamLead(rawAgentName)
+
+    // then
+    expect(result).toEqual({ isEligibleForTeamLead: false })
+  })
+
+  test("returns not eligible for read-only agents", () => {
+    // given
+    const rawAgentName = "Oracle"
+
+    // when
+    const result = resolveCallerTeamLead(rawAgentName)
+
+    // then
+    expect(result).toEqual({
+      displayName: "Oracle",
+      isEligibleForTeamLead: false,
+    })
+  })
+})
+
+describe("shouldReuseCallerLeadSession", () => {
+  test("reuses caller session when caller is eligible and spec has a lead", () => {
+    // given
+    const spec = makeSpec({ leadAgentId: "lead" })
+
+    // when
+    const result = shouldReuseCallerLeadSession(spec, "sisyphus")
+
+    // then
+    expect(result).toBe(true)
+  })
+
+  test("reuses caller session even when lead member is category type", () => {
+    // given
+    const spec = makeSpec({
+      leadAgentId: "lead",
+      members: [
+        { kind: "category", name: "lead", category: "deep", prompt: "lead the team", backendType: "in-process", isActive: true },
+        { kind: "category", name: "worker", category: "quick", prompt: "do work", backendType: "in-process", isActive: true },
+      ],
+    })
+
+    // when
+    const result = shouldReuseCallerLeadSession(spec, "sisyphus")
+
+    // then
+    expect(result).toBe(true)
+  })
+
+  test("reuses caller session even when lead subagent_type differs from caller", () => {
+    // given
+    const spec = makeSpec({
+      leadAgentId: "lead",
+      members: [
+        { kind: "subagent_type", name: "lead", subagent_type: "atlas", backendType: "in-process", isActive: true },
+      ],
+    })
+
+    // when
+    const result = shouldReuseCallerLeadSession(spec, "sisyphus")
+
+    // then
+    expect(result).toBe(true)
+  })
+
+  test("does not reuse when callerAgentTypeId is undefined", () => {
+    // given
+    const spec = makeSpec({ leadAgentId: "lead" })
+
+    // when
+    const result = shouldReuseCallerLeadSession(spec, undefined)
+
+    // then
+    expect(result).toBe(false)
+  })
+
+  test("does not reuse when spec has no leadAgentId", () => {
+    // given
+    const spec = makeSpec({ leadAgentId: undefined })
+
+    // when
+    const result = shouldReuseCallerLeadSession(spec, "sisyphus")
+
+    // then
+    expect(result).toBe(false)
+  })
+})