[nexus] feat(19-03): update API client to use agentId instead of agentSkillsDir

- Add AgentSkillEntry type with skillId, source, installedAt fields
- install() now sends agentId in body not agentSkillsDir
- uninstall() new function that sends agentId as query param
- rollback() now sends agentId in body not agentSkillsDir
- skillGroups.assignGroup/removeGroup no longer accept agentSkillsDir param
- listAgentSkills now returns AgentSkillEntry[] not string[]
- Fix AgentDetail.tsx callers and entry rendering for new AgentSkillEntry type
- Fix SkillDetail.tsx callers to use agentId param

ui/src/api/skillGroups.ts

@@ -1,4 +1,5 @@
 import { api, ApiError } from "./client";
+import type { AgentSkillEntry } from "./skillRegistry";
 
 export type SkillGroupRow = {
   id: string;
@@ -65,18 +66,15 @@ export const skillGroupsApi = {
   listAgentGroups: (agentId: string) =>
     api.get<SkillGroupRow[]>(`/skill-registry/agents/${agentId}/groups`),
 
-  assignGroup: (agentId: string, groupId: string, agentSkillsDir: string) =>
+  assignGroup: (agentId: string, groupId: string) =>
     api.post<AssignResult>(`/skill-registry/agents/${agentId}/groups`, {
       groupId,
-      agentSkillsDir,
     }),
 
-  removeGroup: async (agentId: string, groupId: string, agentSkillsDir: string): Promise<void> => {
+  removeGroup: async (agentId: string, groupId: string): Promise<void> => {
     const res = await fetch(`/api/skill-registry/agents/${agentId}/groups/${groupId}`, {
       method: "DELETE",
       credentials: "include",
-      headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ agentSkillsDir }),
     });
     if (!res.ok && res.status !== 204) {
       const errorBody = await res.json().catch(() => null);
@@ -89,5 +87,5 @@ export const skillGroupsApi = {
   },
 
   listAgentSkills: (agentId: string) =>
-    api.get<string[]>(`/skill-registry/agents/${agentId}/skills`),
+    api.get<AgentSkillEntry[]>(`/skill-registry/agents/${agentId}/skills`),
 };

ui/src/api/skillRegistry.ts

@@ -1,5 +1,11 @@
 import { api } from "./client";
 
+export type AgentSkillEntry = {
+  skillId: string;
+  source: "managed" | "native";
+  installedAt: number;
+};
+
 export type SkillListItem = {
   id: string;
   name: string;
@@ -50,10 +56,12 @@ export const skillRegistryApi = {
     api.get<SkillVersion[]>(`${skillPath(skillId)}/versions`),
   fetch: () =>
     api.post<{ fetched: number; errors: string[] }>("/skill-registry/fetch", {}),
-  install: (skillId: string, agentSkillsDir: string) =>
+  install: (skillId: string, agentId: string) =>
-    api.post(`${skillPath(skillId)}/install`, { agentSkillsDir }),
+    api.post(`${skillPath(skillId)}/install`, { agentId }),
-  rollback: (skillId: string, versionId: string, agentSkillsDir: string) =>
+  uninstall: (skillId: string, agentId: string) =>
-    api.post(`${skillPath(skillId)}/rollback`, { versionId, agentSkillsDir }),
+    api.delete(`${skillPath(skillId)}?agentId=${encodeURIComponent(agentId)}`),
+  rollback: (skillId: string, versionId: string, agentId: string) =>
+    api.post(`${skillPath(skillId)}/rollback`, { versionId, agentId }),
   remove: (skillId: string) =>
     api.delete(skillPath(skillId)),
   getRatings: (skillId: string) =>

ui/src/pages/AgentDetail.tsx

@@ -2440,7 +2440,7 @@ function AgentSkillsTab({
   // Group mutations
   const assignGroupMut = useMutation({
     mutationFn: ({ groupId }: { groupId: string }) =>
-      skillGroupsApi.assignGroup(agent.id, groupId, ""),
+      skillGroupsApi.assignGroup(agent.id, groupId),
     onSuccess: () => {
       void queryClient.invalidateQueries({ queryKey: queryKeys.skillGroups.agentGroups(agent.id) });
       void queryClient.invalidateQueries({ queryKey: queryKeys.skillGroups.agentSkills(agent.id) });
@@ -2450,7 +2450,7 @@ function AgentSkillsTab({
 
   const removeGroupMut = useMutation({
     mutationFn: ({ groupId }: { groupId: string }) =>
-      skillGroupsApi.removeGroup(agent.id, groupId, ""),
+      skillGroupsApi.removeGroup(agent.id, groupId),
     onSuccess: () => {
       void queryClient.invalidateQueries({ queryKey: queryKeys.skillGroups.agentGroups(agent.id) });
       void queryClient.invalidateQueries({ queryKey: queryKeys.skillGroups.agentSkills(agent.id) });
@@ -2735,9 +2735,9 @@ function AgentSkillsTab({
             ) : (
               <ScrollArea className="max-h-[300px] pt-2">
                 <ul className="space-y-1">
-                  {(agentEffectiveSkillsQuery.data ?? []).map((skillId) => (
+                  {(agentEffectiveSkillsQuery.data ?? []).map((entry) => (
-                    <li key={skillId} className="text-sm text-muted-foreground font-mono">
+                    <li key={entry.skillId} className="text-sm text-muted-foreground font-mono">
-                      {skillId}
+                      {entry.skillId}
                     </li>
                   ))}
                 </ul>

ui/src/pages/SkillDetail.tsx

@@ -95,7 +95,7 @@ export function SkillDetail() {
   const [installDialog, setInstallDialog] = useState<{
     skillId: string;
     isUpdate: boolean;
-    agentSkillsDir?: string;
+    agentId?: string;
   } | null>(null);
 
   // Uninstall confirmation dialog state
@@ -149,8 +149,8 @@ export function SkillDetail() {
   };
 
   const installMutation = useMutation({
-    mutationFn: ({ agentSkillsDir }: { agentSkillsDir: string }) =>
+    mutationFn: ({ agentId }: { agentId: string }) =>
-      skillRegistryApi.install(skillId, agentSkillsDir),
+      skillRegistryApi.install(skillId, agentId),
     onSuccess: () => {
       invalidateSkill();
       setInstallDialog(null);
@@ -162,8 +162,8 @@ export function SkillDetail() {
   });
 
   const updateMutation = useMutation({
-    mutationFn: ({ agentSkillsDir }: { agentSkillsDir: string }) =>
+    mutationFn: ({ agentId }: { agentId: string }) =>
-      skillRegistryApi.install(skillId, agentSkillsDir),
+      skillRegistryApi.install(skillId, agentId),
     onSuccess: () => {
       invalidateSkill();
       setInstallDialog(null);
@@ -175,8 +175,8 @@ export function SkillDetail() {
   });
 
   const rollbackMutation = useMutation({
-    mutationFn: ({ versionId, agentSkillsDir }: { versionId: string; agentSkillsDir: string }) =>
+    mutationFn: ({ versionId, agentId }: { versionId: string; agentId: string }) =>
-      skillRegistryApi.rollback(skillId, versionId, agentSkillsDir),
+      skillRegistryApi.rollback(skillId, versionId, agentId),
     onSuccess: () => {
       invalidateSkill();
       pushToast({ title: "Rolled back to previous version", tone: "success" });
@@ -596,16 +596,15 @@ export function SkillDetail() {
           </DialogHeader>
           <div className="py-2">
             <p className="text-sm text-muted-foreground">
-              Agent skills directory is required to install. Enter the path to the agent&apos;s
+              Enter the agent ID to install this skill.
-              skills directory.
             </p>
             <input
               type="text"
               className="mt-2 w-full rounded-md border border-border bg-background px-3 py-2 text-sm focus:outline-none focus:ring-1 focus:ring-ring"
-              placeholder="/path/to/agent/skills"
+              placeholder="Agent ID"
-              value={installDialog?.agentSkillsDir ?? ""}
+              value={installDialog?.agentId ?? ""}
               onChange={(e) =>
-                setInstallDialog((d) => d ? { ...d, agentSkillsDir: e.target.value } : null)
+                setInstallDialog((d) => d ? { ...d, agentId: e.target.value } : null)
               }
             />
           </div>
@@ -614,13 +613,13 @@ export function SkillDetail() {
               Cancel
             </Button>
             <Button
-              disabled={!installDialog?.agentSkillsDir || isMutating}
+              disabled={!installDialog?.agentId || isMutating}
               onClick={() => {
-                if (!installDialog?.agentSkillsDir) return;
+                if (!installDialog?.agentId) return;
                 if (installDialog.isUpdate) {
-                  updateMutation.mutate({ agentSkillsDir: installDialog.agentSkillsDir });
+                  updateMutation.mutate({ agentId: installDialog.agentId });
                 } else {
-                  installMutation.mutate({ agentSkillsDir: installDialog.agentSkillsDir });
+                  installMutation.mutate({ agentId: installDialog.agentId });
                 }
               }}
             >