diff --git a/apps/desktop/electron/main/index.ts b/apps/desktop/electron/main/index.ts
index 971ce6d90..22dff9336 100644
--- a/apps/desktop/electron/main/index.ts
+++ b/apps/desktop/electron/main/index.ts
@@ -1503,6 +1503,32 @@ async function loadUserSkillBody(
   return { id: skill.id, name: skill.name, body: result.body };
 }
 
+/**
+ * Expand a leading `/skill-id extra instructions` draft into the same
+ * `<skill>` block the `Skill` tool returns (issue #142), with the extra text
+ * appended as additional instructions. Returns null when the name is not an
+ * active user skill, so templates and unknown /names keep their existing
+ * behavior.
+ */
+async function expandSkillInvocation(
+  content: string,
+  projectPath: string | null,
+): Promise<{ expanded: string; command: string } | null> {
+  if (!content.startsWith("/")) return null;
+  const tokenEnd = content.search(/[\s]/);
+  const token = tokenEnd === -1 ? content : content.slice(0, tokenEnd);
+  const id = token.slice(1);
+  if (!id || id.includes("/")) return null;
+  const skill = await loadUserSkillBody(id, projectPath).catch(() => null);
+  if (!skill) return null;
+  const rest = tokenEnd === -1 ? "" : content.slice(tokenEnd).trim();
+  const skillBlock = `<skill name="${skill.name}" location="${skill.id}">\n\n${skill.body}\n</skill>`;
+  return {
+    expanded: rest ? `${skillBlock}\n\n${rest}` : skillBlock,
+    command: content.trim(),
+  };
+}
+
 async function resolveEffectiveCommandShell(): Promise<CommandShellCatalog> {
   if (!host) throw new Error("host unavailable");
   const catalog = await host.call<CommandShellCatalog>("commandShells.list");
@@ -7532,8 +7558,20 @@ function registerIpc() {
       description: command.description ?? command.extensionLabel,
       id: trustedExtensionCommandId(command.name),
     }));
+    // User skills (issue #142): active skills join the "/" namespace so they
+    // are discoverable and invocable like templates. Activation scope uses
+    // the window's project, matching the other app-facing surfaces.
+    const skillCommands = (await activeUserSkills(root ?? undefined)).map(
+      (skill) => ({
+        name: skill.id,
+        kind: "skill" as const,
+        title: skill.name,
+        ...(skill.description ? { description: skill.description } : {}),
+      }),
+    );
     // One namespace: builtin aliases win, then project templates, then user
-    // templates, then plugin commands, then extension commands (spec 04 §7).
+    // templates, then plugin commands, then extension commands, then user
+    // skills (spec 04 §7).
     const merged = new Map<
       string,
       ReturnType<typeof builtinComposerCommands>[number]
@@ -7543,6 +7581,7 @@ function registerIpc() {
       ...templateCommands,
       ...pluginCommands,
       ...extensionCommands,
+      ...skillCommands,
     ]) {
       if (!merged.has(command.name)) merged.set(command.name, command);
     }
@@ -7998,7 +8037,9 @@ function registerIpc() {
     // persistence so reseed replays exactly what the model saw; the typed
     // form rides along as `command` for transcript display. Builtin/plugin
     // slash aliases never reach this channel, and unknown /names stay
-    // literal text.
+    // literal text. A /name matching an active user skill expands to the
+    // same <skill> block the `Skill` tool returns (issue #142), with any
+    // extra text appended as additional instructions.
     let promptContent = req.content;
     let slashCommand: string | undefined;
     if (req.content.startsWith("/")) {
@@ -8009,6 +8050,15 @@ function registerIpc() {
         if (expansion) {
           promptContent = expansion.expanded;
           slashCommand = expansion.command;
+        } else {
+          const skillExpansion = await expandSkillInvocation(
+            req.content,
+            root ?? null,
+          );
+          if (skillExpansion) {
+            promptContent = skillExpansion.expanded;
+            slashCommand = skillExpansion.command;
+          }
         }
       } catch (error) {
         logger.app("session", "warn", "slash expansion failed; sending literal text", {
diff --git a/apps/desktop/src/components/ComposerAutocomplete.tsx b/apps/desktop/src/components/ComposerAutocomplete.tsx
index 903c051d8..9b499bfb2 100644
--- a/apps/desktop/src/components/ComposerAutocomplete.tsx
+++ b/apps/desktop/src/components/ComposerAutocomplete.tsx
@@ -44,11 +44,13 @@ const GROUP_KEYS: Record<ComposerCommand["kind"], string> = {
   builtin: "chat.slashGroupApp",
   plugin: "chat.slashGroupPlugins",
   extension: "chat.slashGroupExtensions",
+  skill: "chat.slashGroupSkills",
 };
 
 function CommandIcon({ kind }: { kind: ComposerCommand["kind"] }) {
   if (kind === "template") return <IconSlash size={14} />;
   if (kind === "plugin" || kind === "extension") return <IconPlug size={14} />;
+  if (kind === "skill") return <IconSparkles size={14} />;
   return <IconSparkles size={14} />;
 }
 
diff --git a/apps/desktop/src/hooks/use-composer-autocomplete.ts b/apps/desktop/src/hooks/use-composer-autocomplete.ts
index d23164aaf..55ba34d5e 100644
--- a/apps/desktop/src/hooks/use-composer-autocomplete.ts
+++ b/apps/desktop/src/hooks/use-composer-autocomplete.ts
@@ -41,7 +41,7 @@ let filesCache: {
   truncated: boolean;
 } | null = null;
 
-const COMMAND_GROUP_ORDER = { template: 0, builtin: 1, plugin: 2, extension: 3 } as const;
+const COMMAND_GROUP_ORDER = { template: 0, builtin: 1, plugin: 2, extension: 3, skill: 4 } as const;
 
 function filterCommands(
   commands: ComposerCommand[],
diff --git a/docs/spec/04-ux/04-builtin-commands.md b/docs/spec/04-ux/04-builtin-commands.md
index 21feb26f4..0d131c17a 100644
--- a/docs/spec/04-ux/04-builtin-commands.md
+++ b/docs/spec/04-ux/04-builtin-commands.md
@@ -87,7 +87,10 @@ in the same registry that feeds palette search
 
 Aliases share one namespace with template and plugin command names; builtin
 aliases win collisions, then project templates, then user templates, then
-plugin commands. Selecting an alias inserts `/alias `; sending `/new` or
+plugin commands, then extension commands, then active user skills
+(`~/.agents/skills` / `<project>/.agents/skills`, scope-filtered like the
+rest of the app-facing surfaces). Selecting an alias inserts `/alias `;
+sending `/new` or
 `/compact` alone executes locally without creating an empty prompt. The
 Agent/Plan/Goal aliases also support a prompt body:
 `/agent-mode <prompt>`, `/plan-mode <prompt>`, or `/goal-mode <prompt>` switches
diff --git a/docs/spec/06-delivery/04-e2e-test-plan.md b/docs/spec/06-delivery/04-e2e-test-plan.md
index 333309282..d018600d1 100644
--- a/docs/spec/06-delivery/04-e2e-test-plan.md
+++ b/docs/spec/06-delivery/04-e2e-test-plan.md
@@ -683,6 +683,29 @@ Each scenario is documented in this format:
 - **Status**: Unit-covered (stream processor terminates on the terminal
   event via the pi-ai patch); live-proxy scenario Draft
 
+#### E2E-249: User skills appear in the composer "/" menu and expand on send
+
+- **Preconditions**: At least one enabled global user skill exists under
+  `~/.agents/skills` (or a project skill under `<project>/.agents/skills`);
+  a workspace is open; no template shares the skill's id.
+- **Steps**: 1) Type `/` in the composer. 2) Confirm the skill appears under
+  its own group with name, description, and the skill icon. 3) Type the
+  skill's id to filter and accept the row. 4) Append optional free text and
+  send. 5) Disable the skill in Settings → Agent → Skills, then type `/`
+  again.
+- **Expected**: The "/" menu lists active user skills alongside app, plugin,
+  extension, and template commands, scope-filtered by the open workspace.
+  Sending `/skill-id extra text` persists a prompt whose content is the
+  `<skill>` block (same shape the `Skill` tool returns) followed by the
+  extra text as additional instructions, with `command` set to the typed
+  invocation. Disabled or out-of-scope skills disappear from the menu, and
+  an unknown `/name` stays literal text.
+- **Specs linked**: `04-ux/04-builtin-commands.md` (§7),
+  `03-runtime/03-tools-and-permissions.md`
+- **Acceptance**: C (skills discovery and invocation)
+- **Milestone**: M2
+- **Status**: Documented; automation pending
+
 #### E2E-005E: DeepSeek thinking replay includes reasoning_content on aggregator endpoints
 
 - **Preconditions**: An OpenAI-compatible provider whose base URL is not
diff --git a/docs/zh-CN/spec/04-ux/04-builtin-commands.md b/docs/zh-CN/spec/04-ux/04-builtin-commands.md
index 4688df739..dfee1cf83 100644
--- a/docs/zh-CN/spec/04-ux/04-builtin-commands.md
+++ b/docs/zh-CN/spec/04-ux/04-builtin-commands.md
@@ -76,7 +76,9 @@ type CommandExecutionResult =
 | `/goal-mode` | `builtin.mode.goal` |
 
 别名与模板和插件命令名称共享一个命名空间；冲突时优先使用内置别名，其次是项目模板、
-用户模板和插件命令。选择别名会插入 `/alias `；单独发送 `/new` 或 `/compact` 时，
+用户模板、插件命令、扩展命令，最后是激活的用户技能（`~/.agents/skills` /
+`<project>/.agents/skills`，按激活范围过滤，与其他面向应用的界面一致）。选择别名会插入
+`/alias `；单独发送 `/new` 或 `/compact` 时，
 会在本地执行，不会创建空提示。Agent/Plan/Goal 别名支持附带提示词：
 `/agent-mode <prompt>`、`/plan-mode <prompt>` 或 `/goal-mode <prompt>` 会切换空闲会话
 （或下一个会话默认值），并通过正常提示路径发送 `<prompt>`。不带正文的模式别名仍然
diff --git a/packages/i18n/src/locales/de/index.ts b/packages/i18n/src/locales/de/index.ts
index 16208a65e..ddcc84f1e 100644
--- a/packages/i18n/src/locales/de/index.ts
+++ b/packages/i18n/src/locales/de/index.ts
@@ -213,6 +213,7 @@ export const de = {
     "slashGroupApp": "App-Befehle",
     "slashGroupPlugins": "Plugin-Befehle",
     "slashGroupExtensions": "Erweiterungsbefehle",
+    "slashGroupSkills": "Skill-Befehle",
     "slashEmpty": "Keine übereinstimmenden Befehle",
     "fileMenu": "Dateiverweise",
     "fileReferences": "Von diesem Entwurf referenzierte Dateien",
diff --git a/packages/i18n/src/locales/en/index.ts b/packages/i18n/src/locales/en/index.ts
index 58f1e20ce..43f1aca2f 100644
--- a/packages/i18n/src/locales/en/index.ts
+++ b/packages/i18n/src/locales/en/index.ts
@@ -220,6 +220,7 @@ export const en = {
     slashGroupApp: "App commands",
     slashGroupPlugins: "Plugin commands",
     slashGroupExtensions: "Extension commands",
+    "slashGroupSkills": "Skill commands",
     slashEmpty: "No matching commands",
     fileMenu: "File references",
     fileReferences: "Files referenced by this draft",
diff --git a/packages/i18n/src/locales/es/index.ts b/packages/i18n/src/locales/es/index.ts
index 1d77fdb71..eeaeb0607 100644
--- a/packages/i18n/src/locales/es/index.ts
+++ b/packages/i18n/src/locales/es/index.ts
@@ -213,6 +213,7 @@ export const es = {
     "slashGroupApp": "Comandos de aplicaciones",
     "slashGroupPlugins": "Comandos de complemento",
     "slashGroupExtensions": "Comandos de extensión",
+    "slashGroupSkills": "Comandos de skill",
     "slashEmpty": "No hay comandos coincidentes",
     "fileMenu": "Referencias de archivos",
     "fileReferences": "Archivos a los que hace referencia este borrador",
diff --git a/packages/i18n/src/locales/fr/index.ts b/packages/i18n/src/locales/fr/index.ts
index 4c1f0872c..82080c97d 100644
--- a/packages/i18n/src/locales/fr/index.ts
+++ b/packages/i18n/src/locales/fr/index.ts
@@ -213,6 +213,7 @@ export const fr = {
     "slashGroupApp": "Commandes d'application",
     "slashGroupPlugins": "Commandes du plug-in",
     "slashGroupExtensions": "Commandes d'extension",
+    "slashGroupSkills": "Commandes de skill",
     "slashEmpty": "Aucune commande correspondante",
     "fileMenu": "Références de fichiers",
     "fileReferences": "Fichiers référencés par ce brouillon",
diff --git a/packages/i18n/src/locales/ko/index.ts b/packages/i18n/src/locales/ko/index.ts
index c35395a8d..34ee475cf 100644
--- a/packages/i18n/src/locales/ko/index.ts
+++ b/packages/i18n/src/locales/ko/index.ts
@@ -222,6 +222,7 @@ export const ko = {
     slashGroupApp: "앱 명령",
     slashGroupPlugins: "플러그인 명령",
     slashGroupExtensions: "확장 명령",
+    "slashGroupSkills": "스킬 명령",
     slashEmpty: "일치하는 명령 없음",
     fileMenu: "파일 참조",
     fileReferences: "이 초안에서 참조하는 파일",
diff --git a/packages/i18n/src/locales/tr/index.ts b/packages/i18n/src/locales/tr/index.ts
index 9ce5a85f7..690af415b 100644
--- a/packages/i18n/src/locales/tr/index.ts
+++ b/packages/i18n/src/locales/tr/index.ts
@@ -222,6 +222,7 @@ export const tr = {
     slashGroupApp: "Uygulama komutları",
     slashGroupPlugins: "Eklenti komutları",
     slashGroupExtensions: "Uzantı komutları",
+    "slashGroupSkills": "Skill komutları",
     slashEmpty: "Eşleşen komut yok",
     fileMenu: "Dosya başvuruları",
     fileReferences: "Bu taslağın başvurduğu dosyalar",
diff --git a/packages/i18n/src/locales/zh-CN/index.ts b/packages/i18n/src/locales/zh-CN/index.ts
index 7985b9467..5689c511b 100644
--- a/packages/i18n/src/locales/zh-CN/index.ts
+++ b/packages/i18n/src/locales/zh-CN/index.ts
@@ -215,6 +215,7 @@ export const zhCN = {
     slashGroupApp: "应用命令",
     slashGroupPlugins: "插件命令",
     slashGroupExtensions: "扩展命令",
+    "slashGroupSkills": "技能命令",
     slashEmpty: "没有匹配的指令",
     fileMenu: "引用文件",
     fileReferences: "此草稿引用的文件",
diff --git a/packages/i18n/src/locales/zh-TW/index.ts b/packages/i18n/src/locales/zh-TW/index.ts
index 0e0cd64ef..cbf78fe47 100644
--- a/packages/i18n/src/locales/zh-TW/index.ts
+++ b/packages/i18n/src/locales/zh-TW/index.ts
@@ -215,6 +215,7 @@ export const zhTW = {
     slashGroupApp: "應用命令",
     slashGroupPlugins: "外掛命令",
     slashGroupExtensions: "擴充命令",
+    "slashGroupSkills": "技能命令",
     slashEmpty: "沒有匹配的指令",
     fileMenu: "引用檔案",
     fileReferences: "此草稿引用的檔案",
diff --git a/packages/shared/src/types.ts b/packages/shared/src/types.ts
index c39761aa3..88221d40d 100644
--- a/packages/shared/src/types.ts
+++ b/packages/shared/src/types.ts
@@ -1689,7 +1689,7 @@ export type CommandItem = {
 export type ComposerCommand = {
   /** Slash name typed after "/"; unique across the merged list. */
   name: string;
-  kind: "template" | "builtin" | "plugin" | "extension";
+  kind: "template" | "builtin" | "plugin" | "extension" | "skill";
   /** Display title (templates use their name). */
   title: string;
   description?: string;