diff --git a/agent/agent_init.py b/agent/agent_init.py
index c2021bd16e..79bf7e9fd8 100644
--- a/agent/agent_init.py
+++ b/agent/agent_init.py
@@ -494,6 +494,7 @@ def init_agent(
     read_terminal_callback: callable = None,
     read_preview_callback: callable = None,
     read_window_below_callback: callable = None,
+    setup_mcp_callback: callable = None,
     step_callback: callable = None,
     stream_delta_callback: callable = None,
     interim_assistant_callback: callable = None,
@@ -769,6 +770,7 @@ def init_agent(
     agent.read_terminal_callback = read_terminal_callback
     agent.read_preview_callback = read_preview_callback
     agent.read_window_below_callback = read_window_below_callback
+    agent.setup_mcp_callback = setup_mcp_callback
     agent.step_callback = step_callback
     agent.stream_delta_callback = stream_delta_callback
     agent.interim_assistant_callback = interim_assistant_callback
diff --git a/agent/agent_runtime_helpers.py b/agent/agent_runtime_helpers.py
index 50db73c3b3..d7d5c39ebd 100644
--- a/agent/agent_runtime_helpers.py
+++ b/agent/agent_runtime_helpers.py
@@ -99,7 +99,7 @@ def _ra():
 
 
 AGENT_RUNTIME_POST_HOOK_TOOL_NAMES = frozenset(
-    {"todo", "session_search", "memory", "clarify", "read_terminal", "read_preview", "read_window_below", "delegate_task"}
+    {"todo", "session_search", "memory", "clarify", "read_terminal", "read_preview", "read_window_below", "setup_mcp", "delegate_task"}
 )
 
 
@@ -3025,6 +3025,18 @@ def invoke_tool(agent, function_name: str, function_args: dict, effective_task_i
                 ),
                 next_args,
             )
+    elif function_name == "setup_mcp":
+        def _execute(next_args: dict) -> Any:
+            from tools.setup_mcp_tool import setup_mcp_tool as _setup_mcp_tool
+            return _finish_agent_tool(
+                _setup_mcp_tool(
+                    server=next_args.get("server", ""),
+                    action=next_args.get("action", "install"),
+                    reason=next_args.get("reason", ""),
+                    callback=getattr(agent, "setup_mcp_callback", None),
+                ),
+                next_args,
+            )
     elif function_name == "delegate_task":
         def _execute(next_args: dict) -> Any:
             return _finish_agent_tool(agent._dispatch_delegate_task(next_args), next_args)
diff --git a/agent/prompt_builder.py b/agent/prompt_builder.py
index 212ff624ed..96f3eb4786 100644
--- a/agent/prompt_builder.py
+++ b/agent/prompt_builder.py
@@ -903,7 +903,11 @@ PLATFORM_HINTS = {
         "in your response. Images (.png, .jpg, .webp) appear inline, audio and "
         "video play inline, and other files arrive as download links. You can "
         "also include image URLs in markdown format ![alt](url) and they "
-        "render inline as photos."
+        "render inline as photos. "
+        "When the user asks to add, enable, or authorize an MCP server (or a "
+        "task clearly needs one that is missing), use the setup_mcp tool if "
+        "it is available — it shows an inline consent card right in the chat; "
+        "never hand-edit mcp_servers config for them."
     ),
     "sms": (
         "You are communicating via SMS. Keep responses concise and use plain text "
diff --git a/agent/tool_executor.py b/agent/tool_executor.py
index 00029aabdd..1438cd08fc 100644
--- a/agent/tool_executor.py
+++ b/agent/tool_executor.py
@@ -1900,6 +1900,28 @@ def execute_tool_calls_sequential(agent, assistant_message, messages: list, effe
             tool_duration = time.time() - tool_start_time
             if agent._should_emit_quiet_tool_messages():
                 agent._vprint(f"  {_get_cute_tool_message_impl('read_window_below', function_args, tool_duration, result=function_result)}")
+        elif function_name == "setup_mcp":
+            def _execute(next_args: dict) -> Any:
+                from tools.setup_mcp_tool import setup_mcp_tool as _setup_mcp_tool
+                return _setup_mcp_tool(
+                    server=next_args.get("server", ""),
+                    action=next_args.get("action", "install"),
+                    reason=next_args.get("reason", ""),
+                    callback=getattr(agent, "setup_mcp_callback", None),
+                )
+            function_result, function_args, middleware_trace, _execution_blocked, _execution_dispatched = _managed_values(_run_agent_tool_execution_middleware(
+                agent,
+                function_name=function_name,
+                function_args=function_args,
+                effective_task_id=effective_task_id,
+                tool_call_id=getattr(tool_call, "id", "") or "",
+                execute=_execute,
+                scope_block=_ts_scope_block,
+                display_index=i,
+            ))
+            tool_duration = time.time() - tool_start_time
+            if agent._should_emit_quiet_tool_messages():
+                agent._vprint(f"  {_get_cute_tool_message_impl('setup_mcp', function_args, tool_duration, result=function_result)}")
         elif function_name == "delegate_task":
             tasks_arg = function_args.get("tasks")
             if tasks_arg and isinstance(tasks_arg, list):
diff --git a/run_agent.py b/run_agent.py
index b04002e46a..2cf9c455dc 100644
--- a/run_agent.py
+++ b/run_agent.py
@@ -471,6 +471,7 @@ class AIAgent:
         read_terminal_callback: callable = None,
         read_preview_callback: callable = None,
         read_window_below_callback: callable = None,
+        setup_mcp_callback: callable = None,
         step_callback: callable = None,
         stream_delta_callback: callable = None,
         interim_assistant_callback: callable = None,
@@ -558,6 +559,7 @@ class AIAgent:
             read_terminal_callback=read_terminal_callback,
             read_preview_callback=read_preview_callback,
             read_window_below_callback=read_window_below_callback,
+            setup_mcp_callback=setup_mcp_callback,
             step_callback=step_callback,
             stream_delta_callback=stream_delta_callback,
             interim_assistant_callback=interim_assistant_callback,
diff --git a/tests/tools/test_setup_mcp_tool.py b/tests/tools/test_setup_mcp_tool.py
new file mode 100644
index 0000000000..ae7be1d418
--- /dev/null
+++ b/tests/tools/test_setup_mcp_tool.py
@@ -0,0 +1,75 @@
+"""setup_mcp tool — the desktop inline MCP consent card's tool half.
+
+Behavior contracts:
+- no callback (not the desktop app) → tool_error pointing at the CLI path
+- empty/invalid args → tool_error
+- callback answer passes through as JSON
+- empty callback answer (timeout) → status "unanswered", never an error
+"""
+
+import json
+
+import pytest
+
+from tools.setup_mcp_tool import setup_mcp_tool
+
+
+def test_requires_desktop_callback():
+    result = json.loads(setup_mcp_tool(server="linear", callback=None))
+    assert "error" in result
+    assert "hermes mcp install" in result["error"]
+
+
+def test_requires_server_name():
+    result = json.loads(setup_mcp_tool(server="  ", callback=lambda *a: ""))
+    assert "error" in result
+
+
+def test_rejects_unknown_action():
+    result = json.loads(
+        setup_mcp_tool(server="linear", action="uninstall", callback=lambda *a: "")
+    )
+    assert "error" in result
+    assert "action" in result["error"]
+
+
+def test_passes_through_renderer_outcome():
+    outcome = {"status": "installed", "server": "linear"}
+
+    def cb(server, action, reason):
+        assert server == "linear"
+        assert action == "install"
+        assert reason == "to read tickets"
+        return json.dumps(outcome)
+
+    result = json.loads(
+        setup_mcp_tool(server="linear", action="install", reason="to read tickets", callback=cb)
+    )
+    assert result == outcome
+
+
+def test_timeout_returns_unanswered_not_error():
+    result = json.loads(setup_mcp_tool(server="figma", callback=lambda *a: ""))
+    assert result["status"] == "unanswered"
+    assert result["server"] == "figma"
+
+
+def test_callback_exception_is_tool_error():
+    def cb(*a):
+        raise RuntimeError("gateway went away")
+
+    result = json.loads(setup_mcp_tool(server="figma", callback=cb))
+    assert "error" in result
+
+
+def test_non_json_answer_wrapped_as_error_status():
+    result = json.loads(setup_mcp_tool(server="figma", callback=lambda *a: "garbage"))
+    assert result["status"] == "error"
+
+
+@pytest.mark.parametrize("action", ["install", "enable", "authorize"])
+def test_all_actions_accepted(action):
+    result = json.loads(
+        setup_mcp_tool(server="x", action=action, callback=lambda s, a, r: json.dumps({"status": "declined", "server": s}))
+    )
+    assert result["status"] == "declined"
diff --git a/tools/setup_mcp_tool.py b/tools/setup_mcp_tool.py
new file mode 100644
index 0000000000..765c5028cd
--- /dev/null
+++ b/tools/setup_mcp_tool.py
@@ -0,0 +1,134 @@
+#!/usr/bin/env python3
+"""Propose an MCP server to the user as an inline card in the desktop chat.
+
+The card (install / enable / authorize + decline) lives in the desktop
+renderer, so this tool round-trips through the gateway's blocking-prompt
+bridge — the same one ``clarify`` uses: tui_gateway emits
+``mcp.setup.request``, the renderer walks the user through the flow via the
+existing REST endpoints (catalog install, enable, OAuth), and answers with
+``mcp.setup.respond`` once the flow settles. This module is just schema + a
+thin dispatcher over the platform-injected callback.
+
+Lives in the ``desktop_ui`` toolset, which the GUI gateway enables only for
+desktop-sourced sessions — on every other surface the agent falls back to
+``hermes mcp install <name>`` in the terminal.
+"""
+
+import json
+from typing import Callable, Optional
+
+from tools.registry import registry, tool_error
+
+_ACTIONS = ("install", "enable", "authorize")
+
+
+def setup_mcp_tool(
+    server: str = "",
+    action: str = "install",
+    reason: str = "",
+    callback: Optional[Callable] = None,
+) -> str:
+    """Ask the desktop GUI to run an MCP setup flow; return its JSON outcome."""
+    if callback is None:
+        return tool_error(
+            "setup_mcp is only available in the Hermes desktop app. Use the "
+            "terminal instead: `hermes mcp install <name>` for catalog entries, "
+            "`hermes mcp login <name>` for OAuth."
+        )
+
+    name = (server or "").strip()
+    if not name:
+        return tool_error("server is required — the catalog or config name of the MCP server.")
+
+    action = (action or "install").strip().lower()
+    if action not in _ACTIONS:
+        return tool_error(f"action must be one of {', '.join(_ACTIONS)}.")
+
+    try:
+        raw = callback(name, action, (reason or "").strip())
+    except Exception as exc:
+        return tool_error(f"MCP setup flow failed: {exc}")
+
+    if not raw:
+        # The renderer never answered (timeout / closed window). Distinct from
+        # an explicit decline, which arrives as {"status": "declined"}.
+        return json.dumps(
+            {
+                "status": "unanswered",
+                "server": name,
+                "note": (
+                    "The user did not respond to the setup card. Do not retry "
+                    "immediately; continue without the server or ask in chat."
+                ),
+            },
+            ensure_ascii=False,
+        )
+
+    # Desktop answers with a JSON object; pass it through, else wrap the raw text.
+    try:
+        return json.dumps(json.loads(raw), ensure_ascii=False)
+    except (TypeError, ValueError):
+        return json.dumps({"status": "error", "detail": str(raw)}, ensure_ascii=False)
+
+
+SETUP_MCP_SCHEMA = {
+    "name": "setup_mcp",
+    "description": (
+        "Propose an MCP server to the user as an inline consent card in the "
+        "Hermes desktop chat. The card lets them install a catalog entry, "
+        "re-enable a disabled server, or run an OAuth login — right there, "
+        "without opening the Capabilities tab — and blocks until they act or "
+        "decline. Use when the user asks to add/set up an MCP (e.g. \"add the "
+        "linear mcp\"), or when a task clearly needs one that is missing or "
+        "unauthorized. Never call it twice for the same server after a "
+        "decline. Returns JSON {status: installed|enabled|authorized|declined|"
+        "unanswered|error, server, detail?, tools?}. On declined/unanswered, "
+        "continue without the server. Catalog names: run `hermes mcp catalog` "
+        "in the terminal to list them."
+    ),
+    "parameters": {
+        "type": "object",
+        "properties": {
+            "server": {
+                "type": "string",
+                "description": (
+                    "The server's catalog name (for install) or its name in "
+                    "mcp_servers config (for enable/authorize)."
+                ),
+            },
+            "action": {
+                "type": "string",
+                "enum": ["install", "enable", "authorize"],
+                "description": (
+                    "install: add a catalog entry (prompts for any required "
+                    "keys). enable: re-enable a disabled configured server. "
+                    "authorize: run the OAuth browser flow for a configured "
+                    "server. Defaults to install."
+                ),
+            },
+            "reason": {
+                "type": "string",
+                "description": (
+                    "One short sentence shown on the card: why this server "
+                    "helps right now (e.g. \"To read the JIRA ticket you "
+                    "linked\")."
+                ),
+            },
+        },
+        "required": ["server"],
+    },
+}
+
+
+registry.register(
+    name="setup_mcp",
+    toolset="desktop_ui",
+    schema=SETUP_MCP_SCHEMA,
+    handler=lambda args, **kw: setup_mcp_tool(
+        server=args.get("server", ""),
+        action=args.get("action", "install"),
+        reason=args.get("reason", ""),
+        callback=kw.get("callback"),
+    ),
+    emoji="🔌",
+)
diff --git a/toolsets.py b/toolsets.py
index f33966ebae..26d635043f 100644
--- a/toolsets.py
+++ b/toolsets.py
@@ -279,6 +279,7 @@ TOOLSETS = {
             "open_preview", "read_preview",
             "read_window_below",
             "focus_pane", "react_to_message",
+            "setup_mcp",
         ],
         "includes": []
     },
diff --git a/tui_gateway/methods_prompt.py b/tui_gateway/methods_prompt.py
index d0efe89f9f..8e78724cd8 100644
--- a/tui_gateway/methods_prompt.py
+++ b/tui_gateway/methods_prompt.py
@@ -974,6 +974,15 @@ def _(rid, params: dict) -> dict:
     return _respond(rid, params, "text", allow_expired=True)
 
 
+@method("mcp.setup.respond")
+def _(rid, params: dict) -> dict:
+    # `result` is a JSON string of the setup card's outcome ({status, server,
+    # detail?, tools?}). allow_expired=True: the setup_mcp tool waits 10
+    # minutes, but an OAuth round-trip or a slow install can outlive that —
+    # a late answer must resolve gracefully, not surface a raw 4009.
+    return _respond(rid, params, "result", allow_expired=True)
+
+
 @method("sudo.respond")
 def _(rid, params: dict) -> dict:
     return _respond(rid, params, "password", allow_expired=True)
diff --git a/tui_gateway/server.py b/tui_gateway/server.py
index 14d6dbc2f2..4e15cce335 100644
--- a/tui_gateway/server.py
+++ b/tui_gateway/server.py
@@ -3286,6 +3286,7 @@ def _block(event: str, sid: str, payload: dict, timeout: float | None = 300) ->
         "terminal.read.request",
         "preview.read.request",
         "window.read.request",
+        "mcp.setup.request",
     }:
         _emit(
             f"{event.removesuffix('.request')}.expire",
@@ -4394,7 +4395,8 @@ def _tool_lifecycle_required_for_ui(name: str) -> bool:
     # Desktop renders the clarify choices/question from the tool-call part, then
     # wires request_id from clarify.request. If tool progress is off, suppressing
     # clarify's lifecycle events leaves only the sidebar attention dot visible.
-    return name == "clarify"
+    # setup_mcp is the same shape: its consent card mounts on the tool part.
+    return name in ("clarify", "setup_mcp")
 
 
 def _restart_slash_worker(sid: str, session: dict):
@@ -5877,6 +5879,18 @@ def _agent_cbs(sid: str) -> dict:
             {},
             timeout=30,
         ),
+        # setup_mcp tool (desktop GUI): the renderer shows an inline consent
+        # card and walks the user through install/enable/OAuth via the REST
+        # endpoints, then answers mcp.setup.respond with the JSON outcome.
+        # Long timeout on purpose — the flow can include typing an API key or
+        # a browser OAuth round-trip. Same lifecycle as clarify: on timeout
+        # the tool returns "unanswered" and a late answer is tolerated.
+        "setup_mcp_callback": lambda server, action, reason: _block(
+            "mcp.setup.request",
+            sid,
+            {"server": server, "action": action, "reason": reason},
+            timeout=600,
+        ),
     }
 
     # Interim assistant commentary (text alongside tool calls, or the attempted