feat(lr-c1a2): @ mention shows project-local agents in session input

lib/agents.js

@@ -223,12 +223,56 @@ function discoverAllAgents() {
   return getAll();
 }
 
+// Read all named-agent definitions from a project-local .claude/agents/ directory.
+//
+// projectDir: absolute path to the project root (cwd).
+// Returns: array of { name, slug, description } objects, sorted by name.
+// Returns [] if the directory does not exist or is unreadable — callers treat
+// an empty array as "no project-local agents" and degrade gracefully.
+//
+// This reads the filesystem directly (no SDK subprocess) — it is synchronous
+// and cheap. The agents directory is small (typically 0–20 files).
+function readProjectAgents(projectDir) {
+  if (!projectDir || typeof projectDir !== "string") return [];
+  var agentsDir = path.join(projectDir, ".claude", "agents");
+  var entries;
+  try {
+    entries = fs.readdirSync(agentsDir);
+  } catch (e) {
+    // Directory absent or unreadable — not an error.
+    return [];
+  }
+  var results = [];
+  for (var i = 0; i < entries.length; i++) {
+    var entry = entries[i];
+    if (!entry || !entry.endsWith(".md")) continue;
+    var slug = entry.slice(0, -3); // strip .md
+    if (!slug) continue;
+    var filePath = path.join(agentsDir, entry);
+    var raw;
+    try {
+      raw = fs.readFileSync(filePath, "utf8");
+    } catch (e) {
+      continue;
+    }
+    var parsed = parseFrontmatter(raw);
+    var name = (parsed && parsed.meta && parsed.meta.name) ? String(parsed.meta.name) : slug;
+    var description = (parsed && parsed.meta && parsed.meta.description) ? String(parsed.meta.description) : "";
+    results.push({ name: name, slug: slug, description: description });
+  }
+  results.sort(function (a, b) {
+    return a.name < b.name ? -1 : a.name > b.name ? 1 : 0;
+  });
+  return results;
+}
+
 module.exports = {
   AGENTS_SOURCE_DIR: AGENTS_SOURCE_DIR,
   PLUGINS_CACHE_DIR: PLUGINS_CACHE_DIR,
   parseFrontmatter: parseFrontmatter,
   slugifyAgentName: slugifyAgentName,
   readAgentToolsFromFile: readAgentToolsFromFile,
+  readProjectAgents: readProjectAgents,
   // New SDK-backed surface:
   refresh: refresh,
   getAll: getAll,

lib/project-sessions.js

@@ -183,6 +183,17 @@ function attachSessions(ctx) {
       return true;
     }
 
+    // lr-c1a2 — get_agents returns agents installed in the project's
+    // .claude/agents/ directory (not the SDK global catalog). Used by the
+    // @ mention dropdown in the session input to offer project-local agents.
+    if (msg.type === "get_agents") {
+      var projectAgents = [];
+      try { projectAgents = agentsModule.readProjectAgents(cwd); }
+      catch (e) { console.error("[project-sessions] get_agents failed:", e && e.message ? e.message : e); }
+      sendTo(ws, { type: "project_agents_list", agents: projectAgents });
+      return true;
+    }
+
     // toggle_agent_favorite flips an agent's membership in chattable.json.
     // Required field: name.
     if (msg.type === "toggle_agent_favorite") {

lib/public/css/at-agents.css

@@ -0,0 +1,68 @@
+/* ==========================================================================
+   @ Agent Autocomplete Dropdown (lr-c1a2)
+   ========================================================================== */
+
+.at-agents-menu {
+  display: none;
+  position: absolute;
+  bottom: 100%;
+  left: 0;
+  right: 0;
+  max-height: 220px;
+  overflow-y: auto;
+  background: var(--sidebar-bg);
+  border: 1px solid var(--border);
+  border-radius: 10px;
+  margin-bottom: 6px;
+  box-shadow: 0 4px 12px rgba(var(--shadow-rgb), 0.15);
+  z-index: 11;
+}
+
+.at-agents-menu.visible { display: block; }
+
+.at-agents-item {
+  display: flex;
+  align-items: baseline;
+  padding: 8px 14px;
+  cursor: pointer;
+  gap: 8px;
+  border-bottom: 1px solid var(--border-subtle);
+}
+
+.at-agents-item:last-child { border-bottom: none; }
+
+.at-agents-item:hover,
+.at-agents-item.active {
+  background: var(--sidebar-active);
+}
+
+.at-agents-name {
+  font-size: 13px;
+  font-weight: 600;
+  color: var(--text);
+  white-space: nowrap;
+  flex-shrink: 0;
+}
+
+.at-agents-badge {
+  font-size: 10px;
+  font-weight: 600;
+  color: var(--text-dimmer);
+  background: var(--border-subtle);
+  border-radius: 4px;
+  padding: 1px 5px;
+  text-transform: uppercase;
+  letter-spacing: 0.04em;
+  white-space: nowrap;
+  flex-shrink: 0;
+}
+
+.at-agents-desc {
+  font-size: 12px;
+  color: var(--text-muted);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  flex: 1;
+  min-width: 0;
+}

lib/public/modules/app-messages.js

@@ -15,6 +15,7 @@ import { updateDmBadge, renderSidebarPresence, setMentionActive, renderUserStrip
 import { refreshMobileChatSheet } from './sidebar-mobile.js';
 import { handlePaletteSessionSwitch, setPaletteVersion } from './command-palette.js';
 import { handleAgentsList, handleAgentFavoriteToggled } from './agent-picker.js';
+import { handleProjectAgentsList, requestProjectAgents } from './at-agents.js';
 import { handleFindInSessionResults } from './session-search.js';
 import { handleInputSync, autoResize, resetAutoResize, builtinCommands, setScheduleBtnDisabled } from './input.js';
 import { startThinking, appendThinking, stopThinking, resetThinkingGroup, createToolItem, updateToolExecuting, updateToolResult, markAllToolsDone, closeToolGroup, removeToolFromGroup, resetToolState, getTools, getPlanContent, setPlanContent, renderPlanBanner, renderPlanCard, getTodoTools, handleTodoWrite, handleTaskCreate, handleTaskUpdate, applyDeadSessionTodoCompaction, isPlanFilePath, enableMainInput, addTurnMeta, updateSubagentActivity, addSubagentToolEntry, markSubagentDone, initSubagentStop, updateSubagentProgress, updateSubagentTaskStatus, renderAskUserQuestion, markAskUserAnswered, renderPermissionRequest, markPermissionCancelled, markPermissionResolved, renderElicitationRequest, markElicitationResolved } from './tools.js';
@@ -459,6 +460,10 @@ export function processMessage(msg) {
         handleAgentFavoriteToggled(msg);
         break;
 
+      case "project_agents_list":
+        handleProjectAgentsList(msg);
+        break;
+
       case "session_presence":
         updateSessionPresence(msg.presence || {});
         break;
@@ -498,6 +503,10 @@ export function processMessage(msg) {
         break;
 
       case "session_switched":
+        // Prefetch project agents so the @ menu is ready without a round-trip
+        // the first time the user types @. Best-effort; at-agents.js handles
+        // an empty list gracefully.
+        requestProjectAgents();
         hideHomeHub();
         // Clear any stale replay indicator from a prior interrupted switch
         if (replayLoadingEl) replayLoadingEl.classList.add("hidden");