fix(delegate-task): reject primary agents in task subagent resolution

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/tools/delegate-task/subagent-discovery.ts

@@ -0,0 +1,85 @@
+import { getAgentConfigKey, getAgentDisplayName, stripAgentListSortPrefix } from "../../shared/agent-display-names"
+import { loadUserAgents, loadProjectAgents } from "../../features/claude-code-agent-loader"
+
+export type AgentMode = "subagent" | "primary" | "all" | undefined
+
+export type AgentInfo = {
+  name: string
+  mode?: "subagent" | "primary" | "all"
+  model?: string | { providerID: string; modelID: string }
+}
+
+export function sanitizeSubagentType(subagentType: string): string {
+  return subagentType.trim().replace(/^[\\\/"']+|[\\\/"']+$/g, "").trim()
+}
+
+export function mergeWithClaudeCodeAgents(
+  serverAgents: AgentInfo[],
+  directory: string | undefined,
+): AgentInfo[] {
+  const userAgentsRecord = loadUserAgents()
+  const projectAgentsRecord = loadProjectAgents(directory)
+
+  const toAgentInfoList = (record: Record<string, { mode?: string; model?: AgentInfo["model"] }>): AgentInfo[] =>
+    Object.entries(record).map(([name, config]) => ({
+      name,
+      mode: config.mode as AgentInfo["mode"],
+      model: config.model,
+    }))
+
+  const mergedAgentMap = new Map<string, AgentInfo>()
+  const addIfAbsent = (agent: AgentInfo): void => {
+    const key = agent.name.toLowerCase()
+    if (!mergedAgentMap.has(key)) {
+      mergedAgentMap.set(key, agent)
+    }
+  }
+
+  for (const agent of serverAgents) addIfAbsent(agent)
+  for (const agent of toAgentInfoList(projectAgentsRecord)) addIfAbsent(agent)
+  for (const agent of toAgentInfoList(userAgentsRecord)) addIfAbsent(agent)
+
+  return Array.from(mergedAgentMap.values())
+}
+
+function buildComparableNames(agentName: string): Set<string> {
+  return new Set([
+    agentName,
+    getAgentDisplayName(agentName),
+    getAgentConfigKey(agentName),
+  ].map(name => stripAgentListSortPrefix(name).trim().toLowerCase()))
+}
+
+function matchesRequestedAgent(agent: AgentInfo, requestedAgentName: string): boolean {
+  const comparableNames = buildComparableNames(requestedAgentName)
+  const listedAgentName = stripAgentListSortPrefix(agent.name).trim().toLowerCase()
+  const listedAgentConfigKey = getAgentConfigKey(agent.name).trim().toLowerCase()
+
+  return comparableNames.has(listedAgentName) || comparableNames.has(listedAgentConfigKey)
+}
+
+export function isTaskCallableAgentMode(mode: AgentMode): boolean {
+  return mode === "all" || mode === "subagent"
+}
+
+export function findPrimaryAgentMatch(
+  agents: AgentInfo[],
+  requestedAgentName: string,
+): AgentInfo | undefined {
+  return agents.find(agent => agent.mode === "primary" && matchesRequestedAgent(agent, requestedAgentName))
+}
+
+export function findCallableAgentMatch(
+  agents: AgentInfo[],
+  requestedAgentName: string,
+): AgentInfo | undefined {
+  return agents.find(agent => isTaskCallableAgentMode(agent.mode) && matchesRequestedAgent(agent, requestedAgentName))
+}
+
+export function listCallableAgentNames(agents: AgentInfo[]): string {
+  return agents
+    .filter(agent => isTaskCallableAgentMode(agent.mode))
+    .map(agent => stripAgentListSortPrefix(agent.name))
+    .sort()
+    .join(", ")
+}