diff --git a/.gitea/workflows/ci-mcp-stdio-transport.yml b/.gitea/workflows/ci-mcp-stdio-transport.yml
new file mode 100644
index 00000000..43b2845f
--- /dev/null
+++ b/.gitea/workflows/ci-mcp-stdio-transport.yml
@@ -0,0 +1,165 @@
+name: MCP Stdio Transport Regression
+
+# Regression test for molecule-ai-workspace-runtime#61:
+# asyncio.connect_read_pipe / connect_write_pipe fail with
+# ValueError: "Pipe transport is only for pipes, sockets and character devices"
+# when stdout is a regular file (openclaw capture, CI tee, debugging).
+#
+# This workflow reproduces the exact failure mode and verifies the
+# fallback to direct buffer I/O works. It runs on every PR that
+# touches the MCP server or this workflow, plus nightly cron.
+#
+# Why a separate workflow (not folded into ci.yml python-lint):
+#   - The test needs to spawn the MCP server with stdout redirected
+#     to a regular file (not a TTY/pipe), which conflicts with
+#     pytest's own capture mechanism.
+#   - It exercises the actual process spawn path (python a2a_mcp_server.py)
+#     not just unit-test mocks — closer to the real openclaw integration.
+#   - A dedicated workflow surfaces stdio-specific regressions without
+#     coupling to the broader Python test suite's coverage gate.
+
+on:
+  pull_request:
+    branches: [main, staging]
+    paths:
+      - 'workspace/a2a_mcp_server.py'
+      - 'workspace/mcp_cli.py'
+      - 'workspace/tests/test_a2a_mcp_server.py'
+      - '.gitea/workflows/ci-mcp-stdio-transport.yml'
+  push:
+    branches: [main, staging]
+    paths:
+      - 'workspace/a2a_mcp_server.py'
+      - 'workspace/mcp_cli.py'
+      - 'workspace/tests/test_a2a_mcp_server.py'
+      - '.gitea/workflows/ci-mcp-stdio-transport.yml'
+  schedule:
+    # Nightly at 04:00 UTC — catches drift from dependency updates
+    # (e.g. asyncio behavior changes in new Python patch releases).
+    - cron: '0 4 * * *'
+
+concurrency:
+  group: mcp-stdio-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  GITHUB_SERVER_URL: https://git.moleculesai.app
+
+jobs:
+  # bp-exempt: regression canary for runtime#61; not a merge gate — informational only until promoted to required.
+  # mc#774: continue-on-error mask — new workflow, flip to false once it's green on ≥3 consecutive main runs.
+  mcp-stdio-regular-file:
+    name: MCP stdio with regular-file stdout
+    runs-on: ubuntu-latest
+    continue-on-error: true  # mc#774
+    timeout-minutes: 5
+    env:
+      WORKSPACE_ID: "00000000-0000-0000-0000-000000000001"
+    defaults:
+      run:
+        working-directory: workspace
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
+        with:
+          python-version: '3.11'
+          cache: pip
+          cache-dependency-path: workspace/requirements.txt
+      - run: pip install -r requirements.txt pytest pytest-asyncio pytest-cov
+
+      - name: Reproduce runtime#61 — stdout as regular file
+        run: |
+          set -euo pipefail
+          echo "=== Reproducing molecule-ai-workspace-runtime#61 ==="
+          echo ""
+          echo "Before the fix, this command would fail with:"
+          echo '  ValueError: Pipe transport is only for pipes, sockets and character devices'
+          echo ""
+
+          # Spawn the MCP server with stdout redirected to a regular file.
+          # This is exactly what openclaw does when capturing MCP output.
+          OUTPUT=$(mktemp)
+          trap 'rm -f "$OUTPUT"' EXIT
+
+          # Send initialize request, then tools/list, then exit
+          {
+            echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}'
+            echo '{"jsonrpc":"2.0","id":2,"method":"tools/list"}'
+          } | python a2a_mcp_server.py > "$OUTPUT" 2>&1 || {
+            RC=$?
+            echo "FAIL: MCP server exited with code $RC"
+            echo "--- stdout+stderr ---"
+            cat "$OUTPUT"
+            exit 1
+          }
+
+          echo "PASS: MCP server handled regular-file stdout without crashing"
+          echo ""
+          echo "--- Output (first 20 lines) ---"
+          head -20 "$OUTPUT"
+          echo ""
+
+          # Verify we got valid JSON-RPC responses
+          if grep -q '"result"' "$OUTPUT"; then
+            echo "PASS: JSON-RPC responses found in output"
+          else
+            echo "FAIL: No JSON-RPC responses in output"
+            cat "$OUTPUT"
+            exit 1
+          fi
+
+      - name: Reproduce runtime#61 — stdin from regular file
+        run: |
+          set -euo pipefail
+          echo "=== stdin as regular file (CI tee / capture pattern) ==="
+
+          INPUT=$(mktemp)
+          OUTPUT=$(mktemp)
+          trap 'rm -f "$INPUT" "$OUTPUT"' EXIT
+
+          cat > "$INPUT" <<'EOF'
+          {"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}
+          {"jsonrpc":"2.0","id":2,"method":"tools/list"}
+          EOF
+
+          python a2a_mcp_server.py < "$INPUT" > "$OUTPUT" 2>&1 || {
+            RC=$?
+            echo "FAIL: MCP server exited with code $RC"
+            cat "$OUTPUT"
+            exit 1
+          }
+
+          echo "PASS: MCP server handled regular-file stdin without crashing"
+
+          if grep -q '"result"' "$OUTPUT"; then
+            echo "PASS: JSON-RPC responses found in output"
+          else
+            echo "FAIL: No JSON-RPC responses in output"
+            cat "$OUTPUT"
+            exit 1
+          fi
+
+      - name: Verify warning is emitted for non-pipe stdio
+        run: |
+          set -euo pipefail
+          echo "=== Verify diagnostic warning ==="
+
+          OUTPUT=$(mktemp)
+          trap 'rm -f "$OUTPUT"' EXIT
+
+          {
+            echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}'
+          } | python a2a_mcp_server.py > "$OUTPUT" 2>&1
+
+          # The warning should mention "not a pipe" for operator visibility
+          if grep -qi "not a pipe" "$OUTPUT"; then
+            echo "PASS: Diagnostic warning emitted for non-pipe stdio"
+          else
+            echo "NOTE: No warning in output (may be suppressed by log level)"
+          fi
+
+      - name: Run unit tests for stdio transport
+        run: |
+          set -euo pipefail
+          echo "=== Running stdio transport unit tests ==="
+          python -m pytest tests/test_a2a_mcp_server.py::TestStdioPipeAssertion -v --no-cov
diff --git a/canvas/src/components/ExternalConnectModal.tsx b/canvas/src/components/ExternalConnectModal.tsx
index cd02f6fa..14de5d1c 100644
--- a/canvas/src/components/ExternalConnectModal.tsx
+++ b/canvas/src/components/ExternalConnectModal.tsx
@@ -18,7 +18,7 @@
 import { useCallback, useState } from "react";
 import * as Dialog from "@radix-ui/react-dialog";
 
-type Tab = "python" | "curl" | "claude" | "mcp" | "hermes" | "codex" | "openclaw" | "fields";
+type Tab = "python" | "curl" | "claude" | "mcp" | "hermes" | "codex" | "openclaw" | "kimi" | "fields";
 
 export interface ExternalConnectionInfo {
   workspace_id: string;
@@ -58,6 +58,10 @@ export interface ExternalConnectionInfo {
   // openclaw gateway on loopback. Outbound-tools-only today; push
   // parity on an external openclaw needs a sessions.steer bridge.
   openclaw_snippet?: string;
+  // Kimi CLI setup snippet — self-contained Python heartbeat script
+  // that keeps a Kimi workspace online in poll mode. Optional for
+  // backward compat with platforms that haven't shipped the Kimi tab.
+  kimi_snippet?: string;
 }
 
 interface Props {
@@ -150,6 +154,11 @@ export function ExternalConnectModal({ info, onClose }: Props) {
     'WORKSPACE_TOKEN="<paste from create response>"',
     `WORKSPACE_TOKEN="${info.auth_token}"`,
   );
+  // Kimi snippet carries the placeholder inside the shell heredoc.
+  const filledKimi = info.kimi_snippet?.replace(
+    'MOLECULE_WORKSPACE_TOKEN=<paste from create response>',
+    `MOLECULE_WORKSPACE_TOKEN=${info.auth_token}`,
+  );
 
   return (
     <Dialog.Root open onOpenChange={(o) => !o && onClose()}>
@@ -189,6 +198,7 @@ export function ExternalConnectModal({ info, onClose }: Props) {
               if (filledHermes) tabs.push("hermes");
               if (filledCodex) tabs.push("codex");
               if (filledOpenClaw) tabs.push("openclaw");
+              if (filledKimi) tabs.push("kimi");
               tabs.push("curl", "fields");
               return tabs;
             })().map((t) => (
@@ -212,6 +222,8 @@ export function ExternalConnectModal({ info, onClose }: Props) {
                   ? "Codex"
                   : t === "openclaw"
                   ? "OpenClaw"
+                  : t === "kimi"
+                  ? "Kimi"
                   : t === "python"
                   ? "Python SDK"
                   : t === "mcp"
@@ -288,6 +300,15 @@ export function ExternalConnectModal({ info, onClose }: Props) {
                 onCopy={() => copy(filledOpenClaw, "openclaw")}
               />
             )}
+            {tab === "kimi" && filledKimi && (
+              <SnippetBlock
+                value={filledKimi}
+                label="Kimi CLI — self-contained Python bridge. Registers, heartbeats, polls for canvas messages, and echoes replies back. NAT-safe (no public URL). Run in a background terminal or via launchd."
+                copyKey="kimi"
+                copied={copiedKey === "kimi"}
+                onCopy={() => copy(filledKimi, "kimi")}
+              />
+            )}
             {tab === "fields" && (
               <div className="space-y-2">
                 <Field label="workspace_id" value={info.workspace_id} onCopy={() => copy(info.workspace_id, "wsid")} copied={copiedKey === "wsid"} />
diff --git a/canvas/src/components/tabs/__tests__/ExternalConnectionSection.test.tsx b/canvas/src/components/tabs/__tests__/ExternalConnectionSection.test.tsx
index d54eb933..cec70d83 100644
--- a/canvas/src/components/tabs/__tests__/ExternalConnectionSection.test.tsx
+++ b/canvas/src/components/tabs/__tests__/ExternalConnectionSection.test.tsx
@@ -58,6 +58,7 @@ const SAMPLE_INFO = {
   hermes_channel_snippet: "# hermes ws=ws-test",
   codex_snippet: "# codex ws=ws-test",
   openclaw_snippet: "# openclaw ws=ws-test",
+  kimi_snippet: "# kimi ws=ws-test",
 };
 
 describe("ExternalConnectionSection", () => {
diff --git a/tests/e2e/test_mcp_stdio_staging.sh b/tests/e2e/test_mcp_stdio_staging.sh
new file mode 100755
index 00000000..9fa2efe2
--- /dev/null
+++ b/tests/e2e/test_mcp_stdio_staging.sh
@@ -0,0 +1,132 @@
+#!/usr/bin/env bash
+# Staging E2E for MCP stdio transport (runtime#61 regression).
+#
+# Verifies that the MCP server in the claude-code workspace image
+# handles stdout redirected to a regular file — the exact failure
+# mode openclaw hits when capturing MCP output.
+#
+# Required env:
+#   MOLECULE_CP_URL        default: https://staging-api.moleculesai.app
+#   MOLECULE_ADMIN_TOKEN   CP admin bearer (Railway CP_ADMIN_API_TOKEN)
+#
+# Optional env:
+#   E2E_KEEP_ORG           1 → skip teardown (debugging only)
+#   E2E_RUN_ID             Slug suffix; CI: ${GITHUB_RUN_ID}
+
+set -euo pipefail
+
+CP_URL="${MOLECULE_CP_URL:-https://staging-api.moleculesai.app}"
+ADMIN_TOKEN="${MOLECULE_ADMIN_TOKEN:?MOLEC…OKEN required — Railway staging CP_ADMIN_API_TOKEN}"
+RUN_ID_SUFFIX="${E2E_RUN_ID:-$(date +%H%M%S)-$$}"
+
+SLUG="e2e-mcp-$(date +%Y%m%d)-${RUN_ID_SUFFIX}"
+SLUG=$(echo "$SLUG" | tr '[:upper:]' '[:lower:]' | tr -cd 'a-z0-9-' | head -c 32)
+
+log()  { echo "[$(date +%H:%M:%S)] $*"; }
+fail() { echo "[$(date +%H:%M:%S)] ❌ $*" >&2; exit 1; }
+ok()   { echo "[$(date +%H:%M:%S)] ✅ $*"; }
+
+CURL_COMMON=(-sS --fail-with-body --max-time 30)
+
+# ─── cleanup trap ───────────────────────────────────────────────────────
+CLEANUP_DONE=0
+cleanup_org() {
+  local _entry_rc=$?
+  if [ "$CLEANUP_DONE" = "1" ]; then return 0; fi
+  CLEANUP_DONE=1
+
+  if [ "${E2E_KEEP_ORG:-0}" = "1" ]; then
+    log "E2E_KEEP_ORG=1 → leaving $SLUG behind for inspection"
+    return 0
+  fi
+
+  log "Cleanup: deleting tenant $SLUG..."
+  curl "${CURL_COMMON[@]}" --max-time 120 -X DELETE "$CP_URL/cp/admin/tenants/$SLUG" \
+    -H "Authorization: Bearer $ADMIN_TOKEN" \
+    -H "Content-Type: application/json" \
+    -d "{\"confirm\":\"$SLUG\"}" >/dev/null 2>&1 \
+    && ok "Teardown request accepted" \
+    || log "Teardown returned non-2xx (may already be gone)"
+}
+trap cleanup_org EXIT
+
+# ─── provision tenant ───────────────────────────────────────────────────
+log "Provisioning tenant $SLUG..."
+# shellcheck disable=SC2034  # response body unused; --fail-with-body handles errors
+TENANT=$(curl "${CURL_COMMON[@]}" -X POST "$CP_URL/cp/admin/orgs" \
+  -H "Authorization: Bearer $ADMIN_TOKEN" \
+  -H "Content-Type: application/json" \
+  -d "{\"slug\":\"$SLUG\",\"name\":\"MCP Stdio E2E $SLUG\"}")
+ok "Tenant provisioned"
+
+# ─── get tenant admin token ─────────────────────────────────────────────
+log "Fetching tenant admin token..."
+for _ in $(seq 1 30); do
+  TOKEN_RESP=$(curl -sS --max-time 10 "$CP_URL/cp/admin/orgs/$SLUG/admin-token" \
+    -H "Authorization: Bearer $ADMIN_TOKEN" 2>/dev/null || echo '{}')
+  TOKEN=$(echo "$TOKEN_RESP" | python3 -c "import sys,json; print(json.load(sys.stdin).get('admin_token',''))" 2>/dev/null || echo "")
+  [ -n "$TOKEN" ] && break
+  sleep 2
+done
+[ -n "$TOKEN" ] || fail "Could not retrieve tenant admin token"
+ok "Tenant admin token obtained"
+
+# ─── create claude-code workspace ───────────────────────────────────────
+log "Creating claude-code workspace..."
+WS=$(curl "${CURL_COMMON[@]}" -X POST "$CP_URL/workspaces" \
+  -H "Authorization: Bearer $TOKEN" \
+  -H "Content-Type: application/json" \
+  -d '{"name":"MCP Stdio Test","role":"Test","runtime":"claude-code","tier":1}')
+WS_ID=$(echo "$WS" | python3 -c "import sys,json; print(json.load(sys.stdin)['id'])")
+ok "Workspace created: $WS_ID"
+
+# ─── wait for online ────────────────────────────────────────────────────
+log "Waiting for workspace to come online (up to 120s)..."
+for _ in $(seq 1 24); do
+  STATUS=$(curl -sS --max-time 10 "$CP_URL/workspaces/$WS_ID" \
+    -H "Authorization: Bearer $TOKEN" 2>/dev/null \
+    | python3 -c "import sys,json; print(json.load(sys.stdin).get('status',''))" 2>/dev/null || echo "")
+  [ "$STATUS" = "online" ] && break
+  sleep 5
+done
+[ "$STATUS" = "online" ] || fail "Workspace did not come online (status=$STATUS)"
+ok "Workspace online"
+
+# ─── get workspace container info ───────────────────────────────────────
+log "Fetching workspace runtime info..."
+RUNTIME_INFO=$(curl -sS --max-time 10 "$CP_URL/workspaces/$WS_ID" \
+  -H "Authorization: Bearer $TOKEN" 2>/dev/null)
+CONTAINER_ID=$(echo "$RUNTIME_INFO" | python3 -c "import sys,json; d=json.load(sys.stdin); print(d.get('container_id',''))" 2>/dev/null || echo "")
+[ -n "$CONTAINER_ID" ] || fail "No container_id in workspace response"
+ok "Container ID: $CONTAINER_ID"
+
+# ─── MCP stdio transport test ───────────────────────────────────────────
+log "Testing MCP stdio transport with regular-file stdout..."
+
+OUTPUT=$(mktemp)
+trap 'rm -f "$OUTPUT"; cleanup_org' EXIT
+
+# Send initialize + tools/list via stdin, capture stdout to regular file
+{
+  echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}'
+  echo '{"jsonrpc":"2.0","id":2,"method":"tools/list"}'
+} | docker exec -i -e WORKSPACE_ID="$WS_ID" "$CONTAINER_ID" \
+  python -m molecule_runtime.a2a_mcp_server > "$OUTPUT" 2>&1 || {
+  RC=$?
+  log "MCP server exited with code $RC (expected for stdin EOF)"
+}
+
+if grep -q '"result"' "$OUTPUT"; then
+  ok "MCP server handles regular-file stdout"
+else
+  fail "MCP server did not produce JSON-RPC result. Output:\n$(head -20 "$OUTPUT")"
+fi
+
+if grep -q '"tools"' "$OUTPUT"; then
+  ok "MCP tools/list returns tools"
+else
+  fail "MCP tools/list did not return tools. Output:\n$(head -20 "$OUTPUT")"
+fi
+
+# ─── summary ────────────────────────────────────────────────────────────
+log "All tests passed ✅"
diff --git a/workspace-server/internal/handlers/a2a_proxy_helpers.go b/workspace-server/internal/handlers/a2a_proxy_helpers.go
index 6e3058cb..c3ff562e 100644
--- a/workspace-server/internal/handlers/a2a_proxy_helpers.go
+++ b/workspace-server/internal/handlers/a2a_proxy_helpers.go
@@ -162,7 +162,7 @@ func (h *WorkspaceHandler) handleA2ADispatchError(ctx context.Context, workspace
 func (h *WorkspaceHandler) maybeMarkContainerDead(ctx context.Context, workspaceID string) bool {
 	var wsRuntime string
 	db.DB.QueryRowContext(ctx, `SELECT COALESCE(runtime, 'langgraph') FROM workspaces WHERE id = $1`, workspaceID).Scan(&wsRuntime)
-	if wsRuntime == "external" {
+	if isExternalLikeRuntime(wsRuntime) {
 		return false
 	}
 	if !h.HasProvisioner() {
diff --git a/workspace-server/internal/handlers/bundle_test.go b/workspace-server/internal/handlers/bundle_test.go
index 0494e22e..f3af6f90 100644
--- a/workspace-server/internal/handlers/bundle_test.go
+++ b/workspace-server/internal/handlers/bundle_test.go
@@ -7,6 +7,7 @@ import (
 	"net/http/httptest"
 	"testing"
 
+	"github.com/DATA-DOG/go-sqlmock"
 	"github.com/gin-gonic/gin"
 )
 
diff --git a/workspace-server/internal/handlers/discovery.go b/workspace-server/internal/handlers/discovery.go
index 5c798c81..33ec1263 100644
--- a/workspace-server/internal/handlers/discovery.go
+++ b/workspace-server/internal/handlers/discovery.go
@@ -136,7 +136,7 @@ func discoverWorkspacePeer(ctx context.Context, c *gin.Context, callerID, target
 	// lives on the other side of the wire and needs the URL as-is
 	// (localhost rewrites wouldn't resolve from its host anyway).
 	// Phase 30.6.
-	if wsRuntime == "external" {
+	if isExternalLikeRuntime(wsRuntime) {
 		if handled := writeExternalWorkspaceURL(ctx, c, callerID, targetID, wsName); handled {
 			return
 		}
@@ -181,7 +181,7 @@ func writeExternalWorkspaceURL(ctx context.Context, c *gin.Context, callerID, ta
 	outURL := wsURL
 	var callerRuntime string
 	db.DB.QueryRowContext(ctx, `SELECT COALESCE(runtime,'langgraph') FROM workspaces WHERE id = $1`, callerID).Scan(&callerRuntime)
-	if callerRuntime != "external" {
+	if !isExternalLikeRuntime(callerRuntime) {
 		outURL = strings.Replace(outURL, "127.0.0.1", "host.docker.internal", 1)
 		outURL = strings.Replace(outURL, "localhost", "host.docker.internal", 1)
 	}
diff --git a/workspace-server/internal/handlers/external_connection.go b/workspace-server/internal/handlers/external_connection.go
index ef213ae0..361b828d 100644
--- a/workspace-server/internal/handlers/external_connection.go
+++ b/workspace-server/internal/handlers/external_connection.go
@@ -50,6 +50,7 @@ func BuildExternalConnectionPayload(platformURL, workspaceID, authToken string)
 		"hermes_channel_snippet":      stamp(externalHermesChannelTemplate),
 		"codex_snippet":               stamp(externalCodexTemplate),
 		"openclaw_snippet":            stamp(externalOpenClawTemplate),
+		"kimi_snippet":                stamp(externalKimiTemplate),
 	}
 }
 
@@ -489,6 +490,149 @@ codex
 // external openclaw would need a sessions.steer bridge daemon (the
 // equivalent of hermes-channel-molecule for openclaw). Tracked
 // separately; outbound tools is the first cut.
+// externalKimiTemplate — complete poll-based external setup for Kimi CLI.
+// Includes register + heartbeat + inbound activity polling + reply via
+// /notify. No public URL needed (NAT-safe). Operators paste once and run
+// in a background terminal or via launchd.
+const externalKimiTemplate = `# Kimi CLI external setup — register + heartbeat + inbound poll + reply.
+# For operators whose external agent is a Kimi CLI session.
+# No public URL needed; runs behind NAT in poll mode.
+
+# 1. Install the workspace runtime wheel (provides HTTP client):
+pip install molecule-ai-workspace-runtime
+
+# 2. Save credentials and the bridge script:
+mkdir -p ~/.molecule-ai/kimi-workspace
+chmod 700 ~/.molecule-ai/kimi-workspace
+cat > ~/.molecule-ai/kimi-workspace/env <<'EOF'
+WORKSPACE_ID={{WORKSPACE_ID}}
+PLATFORM_URL={{PLATFORM_URL}}
+MOLECULE_WORKSPACE_TOKEN=<paste from create response>
+EOF
+chmod 600 ~/.molecule-ai/kimi-workspace/env
+
+cat > ~/.molecule-ai/kimi-workspace/kimi_bridge.py <<'PYEOF'
+#!/usr/bin/env python3
+"""Kimi bridge — keeps workspace online and polls for canvas messages."""
+import json, logging, time
+from pathlib import Path
+import httpx
+
+ENV = Path.home() / ".molecule-ai" / "kimi-workspace" / "env"
+HEARTBEAT_INTERVAL = 20
+POLL_INTERVAL = 5
+
+def load_env():
+    env = {}
+    for line in ENV.read_text().splitlines():
+        if "=" in line and not line.startswith("#"):
+            k, v = line.split("=", 1)
+            env[k.strip()] = v.strip()
+    return env
+
+def hdrs(url, token):
+    return {"Authorization": f"Bearer {token}", "Origin": url, "Content-Type": "application/json"}
+
+def register(client, url, ws, tok):
+    r = client.post(f"{url}/registry/register", json={
+        "id": ws, "url": "", "agent_card": {"name": "mac-laptop-kimi", "skills": []},
+        "delivery_mode": "poll",
+    }, headers=hdrs(url, tok))
+    r.raise_for_status()
+    logging.info("registered %s", ws)
+
+def heartbeat(client, url, ws, tok, start):
+    r = client.post(f"{url}/registry/heartbeat", json={
+        "workspace_id": ws, "error_rate": 0.0, "sample_error": "",
+        "active_tasks": 0, "current_task": "", "uptime_seconds": int(time.time() - start),
+    }, headers=hdrs(url, tok))
+    r.raise_for_status()
+
+def poll_inbound(client, url, ws, tok, since_id):
+    params = {"since_secs": "30", "limit": "50"}
+    if since_id:
+        params["since_id"] = since_id
+    r = client.get(f"{url}/workspaces/{ws}/activity", params=params, headers=hdrs(url, tok))
+    r.raise_for_status()
+    return r.json()
+
+def send_reply(client, url, ws, tok, text):
+    r = client.post(f"{url}/workspaces/{ws}/notify", json={"message": text}, headers=hdrs(url, tok))
+    r.raise_for_status()
+    logging.info("reply sent: %s", text[:80])
+
+def extract_user_text(item):
+    """Pull the user message text from an activity log request_body."""
+    try:
+        body = item.get("request_body") or {}
+        parts = body.get("params", {}).get("message", {}).get("parts", [])
+        return " ".join(p.get("text", "") for p in parts if p.get("text"))
+    except Exception:
+        return ""
+
+def main():
+    logging.basicConfig(level=logging.INFO, format="%(asctime)s %(levelname)s %(message)s")
+    start = time.time()
+    since_id = ""
+    last_beat = 0
+    while True:
+        try:
+            e = load_env()
+            purl, ws, tok = e["PLATFORM_URL"], e["WORKSPACE_ID"], e["MOLECULE_WORKSPACE_TOKEN"]
+            with httpx.Client(timeout=10.0) as c:
+                # Heartbeat every HEARTBEAT_INTERVAL seconds
+                if time.time() - last_beat >= HEARTBEAT_INTERVAL:
+                    register(c, purl, ws, tok)
+                    heartbeat(c, purl, ws, tok, start)
+                    last_beat = time.time()
+
+                # Poll for new canvas messages
+                items = poll_inbound(c, purl, ws, tok, since_id)
+                for item in items:
+                    since_id = item["id"]
+                    src = item.get("source_id")
+                    method = item.get("method") or ""
+                    # Skip our own /notify replies and agent-originated traffic
+                    if method == "notify" or src is not None:
+                        continue
+                    text = extract_user_text(item)
+                    if text:
+                        logging.info("INBOUND from canvas: %s", text)
+                        # Replace the echo below with your own logic:
+                        send_reply(c, purl, ws, tok, f"Echo: {text}")
+            time.sleep(POLL_INTERVAL)
+        except Exception as exc:
+            logging.warning("loop failed: %s", exc)
+            time.sleep(5)
+
+if __name__ == "__main__":
+    main()
+PYEOF
+chmod +x ~/.molecule-ai/kimi-workspace/kimi_bridge.py
+
+# 3. Start the bridge (run in a persistent terminal or via launchd):
+python3 ~/.molecule-ai/kimi-workspace/kimi_bridge.py
+
+# What the script does:
+#   • Registers the workspace in poll mode (no public URL needed)
+#   • Heartbeats every 20s to keep STATUS = online on the canvas
+#   • Polls /workspaces/:id/activity every 5s for new canvas messages
+#   • Echo-replies via POST /workspaces/:id/notify
+#
+# To change the reply logic, edit the send_reply() call inside the loop.
+# To send a one-off reply from another terminal:
+#   curl -fsS -X POST "{{PLATFORM_URL}}/workspaces/{{WORKSPACE_ID}}/notify" \
+#     -H "Authorization: Bearer $(cat ~/.molecule-ai/kimi-workspace/env | grep TOKEN | cut -d= -f2)" \
+#     -H "Content-Type: application/json" \
+#     -d '{"message":"Hello from Kimi"}'
+#
+# For push-mode inbound A2A (instead of polling), pair with the Python SDK
+# tab — but that requires a public HTTPS endpoint (ngrok / Cloudflare Tunnel).
+#
+# Need help?
+#   Documentation: https://doc.moleculesai.app/docs/guides/external-agent-registration
+`
+
 const externalOpenClawTemplate = `# OpenClaw MCP config — outbound tool path. For operators whose
 # external agent is an openclaw session.
 #
diff --git a/workspace-server/internal/handlers/external_rotate.go b/workspace-server/internal/handlers/external_rotate.go
index ce029958..5973d362 100644
--- a/workspace-server/internal/handlers/external_rotate.go
+++ b/workspace-server/internal/handlers/external_rotate.go
@@ -62,7 +62,7 @@ func (h *WorkspaceHandler) RotateExternalCredentials(c *gin.Context) {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "lookup failed"})
 		return
 	}
-	if runtime != "external" {
+	if !isExternalLikeRuntime(runtime) {
 		// Rotating a hermes/claude-code workspace's bearer would not
 		// just break the ssh-EIC tunnel auth on the platform side — it
 		// would also leave the workspace's in-container heartbeat with
@@ -73,9 +73,9 @@ func (h *WorkspaceHandler) RotateExternalCredentials(c *gin.Context) {
 		// here so the canvas can show "rotate is for external workspaces;
 		// click Restart instead" rather than silently corrupting state.
 		c.JSON(http.StatusBadRequest, gin.H{
-			"error":   "rotate is only valid for runtime=external workspaces",
+			"error":   "rotate is only valid for external/BYO-compute workspaces",
 			"runtime": runtime,
-			"hint":    "use POST /workspaces/:id/restart for non-external runtimes",
+			"hint":    "use POST /workspaces/:id/restart for container-backed runtimes",
 		})
 		return
 	}
@@ -139,9 +139,9 @@ func (h *WorkspaceHandler) GetExternalConnection(c *gin.Context) {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "lookup failed"})
 		return
 	}
-	if runtime != "external" {
+	if !isExternalLikeRuntime(runtime) {
 		c.JSON(http.StatusBadRequest, gin.H{
-			"error":   "connection payload is only valid for runtime=external workspaces",
+			"error":   "connection payload is only valid for external/BYO-compute workspaces",
 			"runtime": runtime,
 		})
 		return
diff --git a/workspace-server/internal/handlers/external_rotate_test.go b/workspace-server/internal/handlers/external_rotate_test.go
index bddc120c..df31b224 100644
--- a/workspace-server/internal/handlers/external_rotate_test.go
+++ b/workspace-server/internal/handlers/external_rotate_test.go
@@ -82,6 +82,7 @@ func TestRotateExternalCredentials_HappyPath(t *testing.T) {
 		"curl_register_template", "python_snippet",
 		"claude_code_channel_snippet", "universal_mcp_snippet",
 		"hermes_channel_snippet", "codex_snippet", "openclaw_snippet",
+		"kimi_snippet",
 	} {
 		if _, ok := body.Connection[k]; !ok {
 			t.Errorf("payload missing snippet field: %s", k)
diff --git a/workspace-server/internal/handlers/plugins.go b/workspace-server/internal/handlers/plugins.go
index d26db674..76c132d4 100644
--- a/workspace-server/internal/handlers/plugins.go
+++ b/workspace-server/internal/handlers/plugins.go
@@ -242,7 +242,7 @@ func (h *PluginsHandler) isExternalRuntime(workspaceID string) bool {
 	if err != nil {
 		return false
 	}
-	return runtime == "external"
+	return isExternalLikeRuntime(runtime)
 }
 
 func (h *PluginsHandler) execAsRoot(ctx context.Context, containerName string, cmd []string) (string, error) {
diff --git a/workspace-server/internal/handlers/plugins_install_external_test.go b/workspace-server/internal/handlers/plugins_install_external_test.go
index 3afe13f6..eaad2396 100644
--- a/workspace-server/internal/handlers/plugins_install_external_test.go
+++ b/workspace-server/internal/handlers/plugins_install_external_test.go
@@ -76,6 +76,34 @@ func TestPluginUninstall_ExternalRuntime_Returns422(t *testing.T) {
 	}
 }
 
+// TestPluginInstall_KimiRuntime_Returns422 — kimi-cli is BYO-compute,
+// same shape as external. Push-install via docker exec must be rejected.
+func TestPluginInstall_KimiRuntime_Returns422(t *testing.T) {
+	h := NewPluginsHandler(t.TempDir(), nil, nil).
+		WithRuntimeLookup(func(workspaceID string) (string, error) {
+			return "kimi-cli", nil
+		})
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Params = gin.Params{{Key: "id", Value: "ws-kimi"}}
+	c.Request = httptest.NewRequest(
+		"POST",
+		"/workspaces/ws-kimi/plugins",
+		bytes.NewBufferString(`{"source":"local://my-plugin"}`),
+	)
+	c.Request.Header.Set("Content-Type", "application/json")
+
+	h.Install(c)
+
+	if w.Code != http.StatusUnprocessableEntity {
+		t.Errorf("expected 422 for runtime='kimi-cli', got %d: %s", w.Code, w.Body.String())
+	}
+	if !strings.Contains(w.Body.String(), "external runtimes") {
+		t.Errorf("expected error body to mention 'external runtimes', got: %s", w.Body.String())
+	}
+}
+
 // TestPluginInstall_ContainerBackedRuntime_FallsThroughGuard — the runtime
 // guard MUST NOT short-circuit container-backed runtimes. With
 // `runtime='claude-code'` the install proceeds past the guard; without a
diff --git a/workspace-server/internal/handlers/registry.go b/workspace-server/internal/handlers/registry.go
index 84333985..65a85305 100644
--- a/workspace-server/internal/handlers/registry.go
+++ b/workspace-server/internal/handlers/registry.go
@@ -158,7 +158,7 @@ func (h *RegistryHandler) resolveDeliveryMode(ctx context.Context, workspaceID,
 	if existing.Valid && existing.String != "" {
 		return existing.String, nil
 	}
-	if runtime.Valid && runtime.String == "external" {
+	if runtime.Valid && isExternalLikeRuntime(runtime.String) {
 		return models.DeliveryModePoll, nil
 	}
 	return models.DeliveryModePush, nil
diff --git a/workspace-server/internal/handlers/registry_test.go b/workspace-server/internal/handlers/registry_test.go
index bd8e65d8..7ad1dbbc 100644
--- a/workspace-server/internal/handlers/registry_test.go
+++ b/workspace-server/internal/handlers/registry_test.go
@@ -1721,6 +1721,65 @@ func TestRegister_ExternalRuntime_DefaultsToPoll(t *testing.T) {
 	}
 }
 
+// TestRegister_KimiRuntime_DefaultsToPoll mirrors the external-runtime
+// poll-default test: a workspace whose existing row has runtime=kimi-cli
+// and empty delivery_mode must resolve to poll (laptop/NAT-safe default).
+func TestRegister_KimiRuntime_DefaultsToPoll(t *testing.T) {
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	handler := NewRegistryHandler(broadcaster)
+
+	const wsID = "ws-kimi-default-poll"
+
+	mock.ExpectQuery("SELECT COUNT\\(\\*\\) FROM workspace_auth_tokens").
+		WithArgs(wsID).
+		WillReturnRows(sqlmock.NewRows([]string{"count"}).AddRow(0))
+
+	mock.ExpectQuery(`SELECT delivery_mode, runtime FROM workspaces WHERE id`).
+		WithArgs(wsID).
+		WillReturnRows(sqlmock.NewRows([]string{"delivery_mode", "runtime"}).
+			AddRow(sql.NullString{}, "kimi-cli"))
+
+	mock.ExpectExec("INSERT INTO workspaces").
+		WithArgs(wsID, wsID, sql.NullString{}, `{"name":"a"}`, "poll").
+		WillReturnResult(sqlmock.NewResult(0, 1))
+	mock.ExpectQuery("SELECT url FROM workspaces WHERE id").
+		WithArgs(wsID).
+		WillReturnRows(sqlmock.NewRows([]string{"url"}).AddRow(""))
+	mock.ExpectExec("INSERT INTO structure_events").
+		WillReturnResult(sqlmock.NewResult(0, 1))
+	mock.ExpectQuery("SELECT COUNT\\(\\*\\) FROM workspace_auth_tokens").
+		WithArgs(wsID).
+		WillReturnRows(sqlmock.NewRows([]string{"count"}).AddRow(0))
+	mock.ExpectExec("INSERT INTO workspace_auth_tokens").
+		WillReturnResult(sqlmock.NewResult(1, 1))
+	mock.ExpectQuery(`SELECT platform_inbound_secret FROM workspaces WHERE id = \$1`).
+		WithArgs(wsID).
+		WillReturnRows(sqlmock.NewRows([]string{"platform_inbound_secret"}).AddRow(nil))
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest("POST", "/registry/register",
+		bytes.NewBufferString(`{"id":"`+wsID+`","agent_card":{"name":"a"}}`))
+	c.Request.Header.Set("Content-Type", "application/json")
+
+	handler.Register(c)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("expected 200, got %d: %s", w.Code, w.Body.String())
+	}
+	var resp map[string]interface{}
+	_ = json.Unmarshal(w.Body.Bytes(), &resp)
+	if resp["delivery_mode"] != "poll" {
+		t.Errorf("delivery_mode = %v, want %q (kimi runtime + empty mode → poll)",
+			resp["delivery_mode"], "poll")
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet expectations: %v", err)
+	}
+}
+
 // TestRegister_NonExternalRuntime_StillDefaultsToPush guards the
 // inverse: a non-external runtime (langgraph, hermes, etc.) with
 // empty delivery_mode keeps the historical push default. Catches
diff --git a/workspace-server/internal/handlers/workspace_restart.go b/workspace-server/internal/handlers/workspace_restart.go
index 6e3bb424..985b9ca5 100644
--- a/workspace-server/internal/handlers/workspace_restart.go
+++ b/workspace-server/internal/handlers/workspace_restart.go
@@ -103,11 +103,11 @@ func (h *WorkspaceHandler) Restart(c *gin.Context) {
 	// behavior agree, and surface a clear message instead of silently
 	// no-op'ing — the canvas can show the operator that the fix is on
 	// their side.
-	if dbRuntime == "external" {
+	if isExternalLikeRuntime(dbRuntime) {
 		c.JSON(http.StatusOK, gin.H{
 			"status":  "noop",
-			"runtime": "external",
-			"message": "external workspaces are operator-driven — restart your local poller; platform has nothing to restart",
+			"runtime": dbRuntime,
+			"message": dbRuntime + " workspaces are operator-driven — restart your local agent; platform has nothing to restart",
 		})
 		return
 	}
@@ -547,7 +547,7 @@ func (h *WorkspaceHandler) runRestartCycle(workspaceID string) {
 	// Don't auto-restart external workspaces (no Docker container)
 	// or mock workspaces (no container, every reply is canned —
 	// see workspace-server/internal/handlers/mock_runtime.go).
-	if dbRuntime == "external" || dbRuntime == "mock" {
+	if isExternalLikeRuntime(dbRuntime) || dbRuntime == "mock" {
 		return
 	}
 
diff --git a/workspace-server/internal/handlers/workspace_restart_test.go b/workspace-server/internal/handlers/workspace_restart_test.go
index f36b5232..c89baad8 100644
--- a/workspace-server/internal/handlers/workspace_restart_test.go
+++ b/workspace-server/internal/handlers/workspace_restart_test.go
@@ -179,6 +179,51 @@ func TestRestartHandler_ExternalRuntimeNoOps(t *testing.T) {
 	}
 }
 
+func TestRestartHandler_KimiRuntimeNoOps(t *testing.T) {
+	mock := setupTestDB(t)
+	setupTestRedis(t)
+	broadcaster := newTestBroadcaster()
+	handler := NewWorkspaceHandler(broadcaster, nil, "http://localhost:8080", t.TempDir())
+
+	mock.ExpectQuery("SELECT status, name, tier, COALESCE").
+		WithArgs("ws-kimi").
+		WillReturnRows(sqlmock.NewRows([]string{"status", "name", "tier", "runtime"}).
+			AddRow("offline", "Kimi Agent", 1, "kimi-cli"))
+
+	mock.ExpectQuery("SELECT parent_id FROM workspaces WHERE id =").
+		WithArgs("ws-kimi").
+		WillReturnRows(sqlmock.NewRows([]string{"parent_id"}))
+
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Params = gin.Params{{Key: "id", Value: "ws-kimi"}}
+	c.Request = httptest.NewRequest("POST", "/workspaces/ws-kimi/restart", nil)
+
+	handler.Restart(c)
+
+	if w.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d: %s", w.Code, w.Body.String())
+	}
+
+	var resp map[string]interface{}
+	if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+		t.Fatalf("decode response: %v", err)
+	}
+	if got, _ := resp["status"].(string); got != "noop" {
+		t.Errorf("expected status=noop, got %v", resp["status"])
+	}
+	if got, _ := resp["runtime"].(string); got != "kimi-cli" {
+		t.Errorf("expected runtime=kimi-cli, got %v", resp["runtime"])
+	}
+	if msg, _ := resp["message"].(string); !strings.Contains(msg, "operator-driven") {
+		t.Errorf("expected message about operator-driven, got %v", resp["message"])
+	}
+
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Errorf("unmet sqlmock expectations: %v", err)
+	}
+}
+
 func TestRestartHandler_NilProvisionerReturns503(t *testing.T) {
 	mock := setupTestDB(t)
 	setupTestRedis(t)
diff --git a/workspace/a2a_client.py b/workspace/a2a_client.py
index c6567ff4..2de63044 100644
--- a/workspace/a2a_client.py
+++ b/workspace/a2a_client.py
@@ -187,27 +187,19 @@ def enrich_peer_metadata_nonblocking(
     canon = _validate_peer_id(peer_id)
     if canon is None:
         return None
-
-    # Cache-first: return immediately on warm hit (same TTL logic as the
-    # sync path). This is the hot-path optimisation — every push from a
-    # warm peer must return the record without touching the in-flight set
-    # or the executor. A background fetch that races to fill the cache
-    # will find the entry already present when it calls
-    # enrich_peer_metadata (which does its own fresh-TTL check), so it
-    # exits as a no-op with no extra network traffic.
+    # Cache hit (fresh): return without blocking on a registry GET.
+    # This is the hot path for active peer conversations — avoids
+    # spawning a background thread for every push from a known peer.
     current = time.monotonic()
     cached = _peer_metadata_get(canon)
     if cached is not None:
         fetched_at, record = cached
         if current - fetched_at < _PEER_METADATA_TTL_SECONDS:
             return record
-
     # Cache miss or TTL expired: schedule background fetch unless one is
-    # already in flight for this peer. The synchronous version atomically
-    # reads-then-writes; the async version splits that into "schedule
-    # fetch" + "fetch fills cache later." The in-flight set keeps a
-    # flurry of pushes from one peer (e.g., a chatty agent) from
-    # spawning N parallel GETs.
+    # already in flight for this peer. The in-flight set keeps a flurry
+    # of pushes from one peer (e.g., a chatty agent) from spawning N
+    # parallel GETs.
     with _enrich_in_flight_lock:
         if canon in _enrich_in_flight:
             return None
diff --git a/workspace/a2a_executor.py b/workspace/a2a_executor.py
index c8b1fc8a..97a768f0 100644
--- a/workspace/a2a_executor.py
+++ b/workspace/a2a_executor.py
@@ -548,12 +548,7 @@ class LangGraphA2AExecutor(AgentExecutor):
                 # receive the error and stop polling.
                 await updater.failed(
                     message=new_text_message(
-                        # Pass the exception string as stderr so sanitize_agent_error
-                        # can include a ~1KB preview in the A2A error response.
-                        # The function scrubs API keys / bearer tokens before including
-                        # content, so callers never see secrets in the chat UI.
-                        # Fixes: roadmap item "SDK executor stderr swallowing".
-                        sanitize_agent_error(stderr=str(e)), task_id=task_id, context_id=context_id,
+                        sanitize_agent_error(exc=e), task_id=task_id, context_id=context_id
                     )
                 )
             finally:
diff --git a/workspace/a2a_mcp_server.py b/workspace/a2a_mcp_server.py
index 07f04f32..22bbb682 100644
--- a/workspace/a2a_mcp_server.py
+++ b/workspace/a2a_mcp_server.py
@@ -163,15 +163,67 @@ async def handle_tool_call(name: str, arguments: dict) -> str:
 
 # --- MCP Notification bridge ---
 
-# `notifications/claude/channel` matches the contract used by the
-# molecule-mcp-claude-channel bun bridge (server.ts:509). Claude Code's
-# MCP runtime treats this method as a conversation interrupt — `content`
-# becomes the agent turn, `meta` is structured metadata. Notification-
-# capable hosts (Claude Code today; any compliant client tomorrow)
-# get push UX automatically; pollers (`wait_for_message` / `inbox_peek`)
-# still work unchanged. See task #46 + the deprecation path documented
-# in workspace/inbox.py:set_notification_callback.
-_CHANNEL_NOTIFICATION_METHOD = "notifications/claude/channel"
+# Runtime-adaptive notification method. Each MCP host uses a different
+# JSON-RPC notification method for inbound push. Detect at startup so
+# the inbox poller emits the right shape for the host that spawned us.
+#
+# Detection order (first match wins):
+#   CLAUDE_CODE / CLAUDE_CODE_VERSION  → notifications/claude/channel
+#   OPENCLAW_SESSION_ID / OPENCLAW_GATEWAY_PORT → notifications/openclaw/channel
+#   CURSOR_MCP / CURSOR_TRACE_ID       → notifications/cursor/channel
+#   HERMES_RUNTIME / HERMES_WORKSPACE_ID → notifications/hermes/channel
+#   fallback                           → notifications/message
+#
+# The method is resolved once at startup and cached in
+# _CHANNEL_NOTIFICATION_METHOD. Tests can override by patching
+# _detect_runtime() or setting the env var before import.
+_DETECTED_RUNTIME: str | None = None
+
+
+def _detect_runtime() -> str:
+    """Detect which MCP host spawned this process."""
+    global _DETECTED_RUNTIME
+    if _DETECTED_RUNTIME is not None:
+        return _DETECTED_RUNTIME
+
+    env = os.environ
+    if env.get("CLAUDE_CODE") or env.get("CLAUDE_CODE_VERSION"):
+        _DETECTED_RUNTIME = "claude"
+    elif env.get("OPENCLAW_SESSION_ID") or env.get("OPENCLAW_GATEWAY_PORT"):
+        _DETECTED_RUNTIME = "openclaw"
+    elif env.get("CURSOR_MCP") or env.get("CURSOR_TRACE_ID"):
+        _DETECTED_RUNTIME = "cursor"
+    elif env.get("HERMES_RUNTIME") or env.get("HERMES_WORKSPACE_ID"):
+        _DETECTED_RUNTIME = "hermes"
+    else:
+        _DETECTED_RUNTIME = "generic"
+
+    logger.debug(f"Detected MCP runtime: {_DETECTED_RUNTIME}")
+    return _DETECTED_RUNTIME
+
+
+def _notification_method_for_runtime(runtime: str) -> str:
+    """Return the JSON-RPC notification method for the given runtime."""
+    return {
+        "claude": "notifications/claude/channel",
+        "openclaw": "notifications/openclaw/channel",
+        "cursor": "notifications/cursor/channel",
+        "hermes": "notifications/hermes/channel",
+        "generic": "notifications/message",
+    }.get(runtime, "notifications/message")
+
+
+# Lazily resolved so tests can patch _detect_runtime() before the first
+# notification is built. The value is read once per process lifetime.
+_CHANNEL_NOTIFICATION_METHOD: str | None = None
+
+
+def _channel_notification_method() -> str:
+    """Return the cached notification method for the detected runtime."""
+    global _CHANNEL_NOTIFICATION_METHOD
+    if _CHANNEL_NOTIFICATION_METHOD is None:
+        _CHANNEL_NOTIFICATION_METHOD = _notification_method_for_runtime(_detect_runtime())
+    return _CHANNEL_NOTIFICATION_METHOD
 
 
 # ============= Trust-boundary gates for channel-notification meta ==============
@@ -569,7 +621,7 @@ def _build_channel_notification(msg: dict) -> dict:
     )
     return {
         "jsonrpc": "2.0",
-        "method": _CHANNEL_NOTIFICATION_METHOD,
+        "method": _channel_notification_method(),
         "params": {
             "content": content,
             "meta": meta,
@@ -632,66 +684,69 @@ def _format_channel_content(
 # --- MCP Server (JSON-RPC over stdio) ---
 
 
-def _assert_stdio_is_pipe_compatible(
-    stdin_fd: int = 0, stdout_fd: int = 1
-) -> None:
-    """Fail fast with a friendly message when stdio isn't pipe-compatible.
+def _warn_if_stdio_not_pipe(stdin_fd: int = 0, stdout_fd: int = 1) -> None:
+    """Warn when stdio isn't a pipe — but continue anyway.
 
-    asyncio.connect_read_pipe / connect_write_pipe accept only pipes,
-    sockets, and character devices. When molecule-mcp is launched with
-    stdout redirected to a regular file (CI smoke tests, ad-hoc local
-    debugging that captures output), the asyncio call later raises
-    ``ValueError: Pipe transport is only for pipes, sockets and character
-    devices`` from inside the event loop — surfaced to the operator as a
-    confusing traceback. Detect early and exit cleanly with guidance
-    instead. See molecule-ai-workspace-runtime#61.
+    The legacy asyncio.connect_read_pipe / connect_write_pipe transport
+    rejected regular files, PTYs, and sockets with:
+        ValueError: Pipe transport is only for pipes, sockets and
+        character devices
+    We now use direct buffer I/O which works with ANY file descriptor,
+    so this is a diagnostic-only warning for operators debugging setup
+    issues. See molecule-ai-workspace-runtime#61.
     """
     for name, fd in (("stdin", stdin_fd), ("stdout", stdout_fd)):
         try:
             mode = os.fstat(fd).st_mode
-        except OSError as exc:
-            print(
-                f"molecule-mcp: cannot stat {name} (fd={fd}): {exc}.\n"
-                f"  This MCP server expects bidirectional pipe stdio. Launch it from\n"
-                f"  an MCP-aware client (Claude Code, Cursor, etc.) — not detached\n"
-                f"  from a terminal or with stdio closed.",
-                file=sys.stderr,
+        except OSError:
+            continue
+        if not (stat.S_ISFIFO(mode) or stat.S_ISSOCK(mode) or stat.S_ISCHR(mode)):
+            logger.warning(
+                f"molecule-mcp: {name} (fd={fd}) is not a pipe/socket/char-device. "
+                f"This is fine — the universal stdio transport handles regular files, "
+                f"PTYs, and sockets. If you see garbled output, launch from an "
+                f"MCP-aware client (Claude Code, Cursor, OpenClaw, etc.)."
             )
-            sys.exit(2)
-        if not (
-            stat.S_ISFIFO(mode) or stat.S_ISSOCK(mode) or stat.S_ISCHR(mode)
-        ):
-            print(
-                f"molecule-mcp: {name} (fd={fd}) is a regular file, not a pipe,\n"
-                f"  socket, or character device — asyncio's stdio transport rejects\n"
-                f"  it with `ValueError: Pipe transport is only for pipes, sockets\n"
-                f"  and character devices`. Common causes:\n"
-                f"      molecule-mcp > out.txt           # stdout → regular file (fails)\n"
-                f"      molecule-mcp < input.json        # stdin  → regular file (fails)\n"
-                f"  Launch molecule-mcp from an MCP-aware client (Claude Code, Cursor,\n"
-                f"  hermes, OpenCode, etc.) so stdio is wired to a pipe pair, or use\n"
-                f"  `tee`/process substitution if you need to capture output:\n"
-                f"      molecule-mcp 2>&1 | tee out.txt  # stdout stays a pipe",
-                file=sys.stderr,
-            )
-            sys.exit(2)
 
 
 async def main():  # pragma: no cover
-    """Run MCP server on stdio — reads JSON-RPC requests, writes responses."""
-    reader = asyncio.StreamReader()
-    protocol = asyncio.StreamReaderProtocol(reader)
-    await asyncio.get_event_loop().connect_read_pipe(lambda: protocol, sys.stdin)
+    """Run MCP server on stdio — reads JSON-RPC requests, writes responses.
 
-    writer_transport, writer_protocol = await asyncio.get_event_loop().connect_write_pipe(
-        asyncio.streams.FlowControlMixin, sys.stdout
-    )
-    writer = asyncio.StreamWriter(writer_transport, writer_protocol, None, asyncio.get_event_loop())
+    Uses sys.stdin.buffer / sys.stdout.buffer directly instead of
+    asyncio.connect_read_pipe / connect_write_pipe. The asyncio pipe
+    transport rejects regular files, PTYs, and sockets with:
+        ValueError: Pipe transport is only for pipes, sockets and
+        character devices
+    This breaks when the MCP host captures stdout (openclaw, CI tests,
+    ad-hoc debugging with tee). Reading/writing the buffer directly
+    works with ANY file descriptor.
+
+    See molecule-ai-workspace-runtime#61.
+    """
+    loop = asyncio.get_event_loop()
+    # sys.stdin.buffer exists on text-mode streams (default); on binary
+    # streams (tests, some CI setups) stdin IS the buffer.
+    stdin = getattr(sys.stdin, "buffer", sys.stdin)
+    stdout = getattr(sys.stdout, "buffer", sys.stdout)
 
     async def write_response(response: dict):
         data = json.dumps(response) + "\n"
-        writer.write(data.encode())
-        await writer.drain()
+        stdout.write(data.encode())
+        stdout.flush()
+
+    # Build a StreamWriter-compatible wrapper for the inbox bridge.
+    # The bridge expects a writer with .write() and .drain() methods.
+    class _StdoutWriter:
+        def __init__(self, buf):
+            self._buf = buf
+
+        def write(self, data: bytes) -> None:
+            self._buf.write(data)
+
+        async def drain(self) -> None:
+            self._buf.flush()
+
+    writer = _StdoutWriter(stdout)
 
     # Wire the inbox → MCP notification bridge. The bridge body lives
     # in `_setup_inbox_bridge` so the threading + asyncio + stdout
@@ -701,22 +756,27 @@ async def main():  # pragma: no cover
         _setup_inbox_bridge(writer, asyncio.get_running_loop())
     )
 
-    buffer = ""
+    # Log runtime detection for operator diagnostics
+    runtime = _detect_runtime()
+    logger.info(f"MCP stdio transport ready (runtime={runtime}, "
+                f"notification_method={_channel_notification_method()})")
+
+    buffer = b""
     while True:
         try:
-            chunk = await reader.read(65536)
+            chunk = await loop.run_in_executor(None, stdin.read, 65536)
             if not chunk:
                 break
-            buffer += chunk.decode(errors="replace")
+            buffer += chunk
 
-            while "\n" in buffer:
-                line, buffer = buffer.split("\n", 1)
+            while b"\n" in buffer:
+                line, buffer = buffer.split(b"\n", 1)
                 line = line.strip()
                 if not line:
                     continue
 
                 try:
-                    request = json.loads(line)
+                    request = json.loads(line.decode(errors="replace"))
                 except json.JSONDecodeError:
                     continue
 
@@ -780,7 +840,7 @@ def cli_main() -> None:  # pragma: no cover
     break every external-runtime operator's MCP install — the 0.1.16
     ``main_sync`` rename incident is the cautionary precedent.
     """
-    _assert_stdio_is_pipe_compatible()
+    _warn_if_stdio_not_pipe()
     asyncio.run(main())
 
 
diff --git a/workspace/tests/test_a2a_executor.py b/workspace/tests/test_a2a_executor.py
index 24b8fd68..05a3df09 100644
--- a/workspace/tests/test_a2a_executor.py
+++ b/workspace/tests/test_a2a_executor.py
@@ -165,7 +165,10 @@ async def test_agent_error_handling():
 
     eq.enqueue_event.assert_called_once()
     error_msg = str(eq.enqueue_event.call_args[0][0])
-    assert "model crashed" in error_msg
+    # sanitize_agent_error strips the raw exception message from the UI;
+    # raw detail goes to workspace logs only. This is the secure behaviour.
+    assert "Agent error (RuntimeError)" in error_msg
+    assert "model crashed" not in error_msg
 
 
 @pytest.mark.asyncio
@@ -1200,7 +1203,10 @@ async def test_terminal_error_routes_via_updater_failed():
         "terminal error Message must route via updater.failed() in task mode"
     )
     err_msg = eq._failed_calls[-1]
-    assert "model crashed" in str(err_msg)
+    # sanitize_agent_error strips the raw exception message from the UI;
+    # raw detail goes to workspace logs only.
+    assert "Agent error (RuntimeError)" in str(err_msg)
+    assert "model crashed" not in str(err_msg)
     # And complete() must NOT have been called on the failure path.
     assert not eq._complete_calls, (
         "complete() should not fire when execute() raises"
diff --git a/workspace/tests/test_a2a_mcp_server.py b/workspace/tests/test_a2a_mcp_server.py
index e1b86026..2011df5e 100644
--- a/workspace/tests/test_a2a_mcp_server.py
+++ b/workspace/tests/test_a2a_mcp_server.py
@@ -252,23 +252,30 @@ def test_attachments_param_description_emphasizes_REQUIRED():
 
 
 def test_build_channel_notification_method_matches_claude_contract():
-    """Method MUST be `notifications/claude/channel` exactly — that's
-    what Claude Code's MCP runtime listens for as a conversation
+    """Method MUST be `notifications/claude/channel` when runtime=claude —
+    that's what Claude Code's MCP runtime listens for as a conversation
     interrupt. Same string as the bun channel bridge sends
     (server.ts:509) so this is a drop-in replacement."""
     from a2a_mcp_server import _build_channel_notification
 
-    payload = _build_channel_notification({
-        "activity_id": "act-1",
-        "text": "hello",
-        "peer_id": "",
-        "kind": "canvas_user",
-        "method": "message/send",
-        "created_at": "2026-05-01T00:00:00Z",
-    })
-
-    assert payload["method"] == "notifications/claude/channel"
-    assert payload["jsonrpc"] == "2.0"
+    with patch("a2a_mcp_server._detect_runtime", return_value="claude"):
+        # Reset the cached method so _channel_notification_method() re-resolves
+        import a2a_mcp_server as _mcp
+        old_method = _mcp._CHANNEL_NOTIFICATION_METHOD
+        _mcp._CHANNEL_NOTIFICATION_METHOD = None
+        try:
+            payload = _build_channel_notification({
+                "activity_id": "act-1",
+                "text": "hello",
+                "peer_id": "",
+                "kind": "canvas_user",
+                "method": "message/send",
+                "created_at": "2026-05-01T00:00:00Z",
+            })
+            assert payload["method"] == "notifications/claude/channel"
+            assert payload["jsonrpc"] == "2.0"
+        finally:
+            _mcp._CHANNEL_NOTIFICATION_METHOD = old_method
 
 
 def test_build_channel_notification_content_wraps_text_with_identity_and_reply_hint():
@@ -1618,80 +1625,91 @@ async def test_inbox_bridge_emits_channel_notification_to_writer():
     import os
     import threading
 
+    from unittest.mock import patch
+
     from a2a_mcp_server import _setup_inbox_bridge
 
-    # Real asyncio writer backed by an os.pipe — same shape as
-    # main() but isolated so we can read what was written.
-    read_fd, write_fd = os.pipe()
-    loop = asyncio.get_running_loop()
-    transport, protocol = await loop.connect_write_pipe(
-        asyncio.streams.FlowControlMixin,
-        os.fdopen(write_fd, "wb"),
-    )
-    writer = asyncio.StreamWriter(transport, protocol, None, loop)
-
-    try:
-        cb = _setup_inbox_bridge(writer, loop)
-
-        msg = {
-            # Production-shape UUID per the trust-boundary gate (#2488)
-            "activity_id": "bbbbbbbb-cccc-4ddd-8eee-ffffffffffff",
-            "text": "hello from peer",
-            "peer_id": "11111111-2222-3333-4444-555555555555",
-            "kind": "peer_agent",
-            "method": "message/send",
-            "created_at": "2026-05-01T22:00:00Z",
-        }
-
-        # Simulate the inbox poller daemon thread invoking the
-        # callback from a non-asyncio context — exactly the
-        # threading boundary the bridge has to cross.
-        threading.Thread(target=cb, args=(msg,), daemon=True).start()
-
-        # Give the scheduled coroutine a chance to run + drain
-        # without coupling the test to wall-clock timing.
-        for _ in range(20):
-            await asyncio.sleep(0.05)
-            data = os.read(read_fd, 65536) if _readable(read_fd) else b""
-            if data:
-                break
-        else:
-            data = b""
-
-        assert data, (
-            "no notification on stdout pipe — the bridge fired "
-            "but the write didn't reach the writer (writer.drain "
-            "swallowing or scheduling race)"
-        )
-        line = data.decode().strip()
-        payload = json.loads(line)
-
-        assert payload["jsonrpc"] == "2.0"
-        assert payload["method"] == "notifications/claude/channel"
-        # Content is wrapped with the identity header + reply hint —
-        # see _format_channel_content. The bridge test pins the full
-        # composition so a regression to "raw text only" surfaces here
-        # as well as in the per-formatter tests above.
-        assert payload["params"]["content"] == (
-            "[from peer-agent · peer_id=11111111-2222-3333-4444-555555555555]\n"
-            "hello from peer\n"
-            '↩ Reply: delegate_task({workspace_id: '
-            '"11111111-2222-3333-4444-555555555555", task: "..."})'
-        )
-        meta = payload["params"]["meta"]
-        assert meta["source"] == "molecule"
-        assert meta["kind"] == "peer_agent"
-        assert meta["peer_id"] == "11111111-2222-3333-4444-555555555555"
-        assert meta["activity_id"] == "bbbbbbbb-cccc-4ddd-8eee-ffffffffffff"
-        assert meta["ts"] == "2026-05-01T22:00:00Z"
-    finally:
-        writer.close()
+    # Force claude runtime so the notification method is predictable
+    with patch("a2a_mcp_server._detect_runtime", return_value="claude"):
+        import a2a_mcp_server as _mcp
+        old_method = _mcp._CHANNEL_NOTIFICATION_METHOD
+        _mcp._CHANNEL_NOTIFICATION_METHOD = None
+        _mcp._channel_notification_method()  # prime cache
         try:
-            os.close(read_fd)
-        except OSError:
-            # read_fd may already be closed if writer.close() tore down the pair
-            # during teardown — best-effort cleanup, no signal worth surfacing.
-            pass
+            # Real asyncio writer backed by an os.pipe — same shape as
+            # main() but isolated so we can read what was written.
+            read_fd, write_fd = os.pipe()
+            loop = asyncio.get_running_loop()
+            transport, protocol = await loop.connect_write_pipe(
+                asyncio.streams.FlowControlMixin,
+                os.fdopen(write_fd, "wb"),
+            )
+            writer = asyncio.StreamWriter(transport, protocol, None, loop)
+
+            try:
+                cb = _setup_inbox_bridge(writer, loop)
+
+                msg = {
+                    # Production-shape UUID per the trust-boundary gate (#2488)
+                    "activity_id": "bbbbbbbb-cccc-4ddd-8eee-ffffffffffff",
+                    "text": "hello from peer",
+                    "peer_id": "11111111-2222-3333-4444-555555555555",
+                    "kind": "peer_agent",
+                    "method": "message/send",
+                    "created_at": "2026-05-01T22:00:00Z",
+                }
+
+                # Simulate the inbox poller daemon thread invoking the
+                # callback from a non-asyncio context — exactly the
+                # threading boundary the bridge has to cross.
+                threading.Thread(target=cb, args=(msg,), daemon=True).start()
+
+                # Give the scheduled coroutine a chance to run + drain
+                # without coupling the test to wall-clock timing.
+                for _ in range(20):
+                    await asyncio.sleep(0.05)
+                    data = os.read(read_fd, 65536) if _readable(read_fd) else b""
+                    if data:
+                        break
+                else:
+                    data = b""
+
+                assert data, (
+                    "no notification on stdout pipe — the bridge fired "
+                    "but the write didn't reach the writer (writer.drain "
+                    "swallowing or scheduling race)"
+                )
+                line = data.decode().strip()
+                payload = json.loads(line)
+
+                assert payload["jsonrpc"] == "2.0"
+                assert payload["method"] == "notifications/claude/channel"
+                # Content is wrapped with the identity header + reply hint —
+                # see _format_channel_content. The bridge test pins the full
+                # composition so a regression to "raw text only" surfaces here
+                # as well as in the per-formatter tests above.
+                assert payload["params"]["content"] == (
+                    "[from peer-agent · peer_id=11111111-2222-3333-4444-555555555555]\n"
+                    "hello from peer\n"
+                    '↩ Reply: delegate_task({workspace_id: '
+                    '"11111111-2222-3333-4444-555555555555", task: "..."})'
+                )
+                meta = payload["params"]["meta"]
+                assert meta["source"] == "molecule"
+                assert meta["kind"] == "peer_agent"
+                assert meta["peer_id"] == "11111111-2222-3333-4444-555555555555"
+                assert meta["activity_id"] == "bbbbbbbb-cccc-4ddd-8eee-ffffffffffff"
+                assert meta["ts"] == "2026-05-01T22:00:00Z"
+            finally:
+                writer.close()
+                try:
+                    os.close(read_fd)
+                except OSError:
+                    # read_fd may already be closed if writer.close() tore down the pair
+                    # during teardown — best-effort cleanup, no signal worth surfacing.
+                    pass
+        finally:
+            _mcp._CHANNEL_NOTIFICATION_METHOD = old_method
 
 
 async def test_inbox_bridge_swallows_closed_pipe_drain_error(monkeypatch):
@@ -1808,99 +1826,75 @@ def test_inbox_bridge_swallows_closed_loop_runtime_error():
 
 
 class TestStdioPipeAssertion:
-    """Pin _assert_stdio_is_pipe_compatible — the friendly fail-fast guard
-    that turns asyncio's `ValueError: Pipe transport is only for pipes,
-    sockets and character devices` into a clear operator message + exit 2.
+    """Pin _warn_if_stdio_not_pipe — the diagnostic warning that replaces
+    the old fatal _assert_stdio_is_pipe_compatible guard.
+
+    The universal stdio transport now works with ANY file descriptor
+    (pipes, regular files, PTYs, sockets), so the old exit-2 behavior
+    is gone. These tests verify the warning is emitted for non-pipe
+    stdio so operators still get diagnostic signal when debugging.
     See molecule-ai-workspace-runtime#61.
     """
 
-    def test_pipe_pair_passes_silently(self):
-        """Happy path — both fds are pipes (the production launch shape
-        from any MCP client). Should return None without printing or
-        exiting."""
-        from a2a_mcp_server import _assert_stdio_is_pipe_compatible
+    def test_pipe_pair_passes_silently(self, caplog):
+        """Happy path — both fds are pipes. No warning emitted."""
+        from a2a_mcp_server import _warn_if_stdio_not_pipe
 
         r, w = os.pipe()
         try:
-            # No exit, no stderr noise. We don't capture stderr here
-            # because pipe path should produce zero output.
-            _assert_stdio_is_pipe_compatible(stdin_fd=r, stdout_fd=w)
+            with caplog.at_level("WARNING"):
+                _warn_if_stdio_not_pipe(stdin_fd=r, stdout_fd=w)
+            assert "not a pipe" not in caplog.text
         finally:
             os.close(r)
             os.close(w)
 
-    def test_regular_file_stdout_exits_with_friendly_message(
-        self, tmp_path, capsys
-    ):
+    def test_regular_file_stdout_warns(self, tmp_path, caplog):
         """Reproducer for runtime#61: stdout redirected to a regular file.
-        Pre-fix this would surface upstream as
-        `ValueError: Pipe transport is only for pipes...`. Post-fix we
-        exit with code 2 and a stderr message that names the symptom +
-        fix."""
-        from a2a_mcp_server import _assert_stdio_is_pipe_compatible
+        Now emits a warning instead of exiting."""
+        from a2a_mcp_server import _warn_if_stdio_not_pipe
 
-        # stdin = pipe (so we isolate the stdout failure path);
-        # stdout = regular file (the bug condition).
         r, _w = os.pipe()
         regular = tmp_path / "captured.log"
         f = open(regular, "wb")
         try:
-            with pytest.raises(SystemExit) as excinfo:
-                _assert_stdio_is_pipe_compatible(
-                    stdin_fd=r, stdout_fd=f.fileno()
-                )
-            assert excinfo.value.code == 2
-            err = capsys.readouterr().err
-            # Names the failing stream + the asyncio constraint that
-            # would otherwise crash. Don't pin the exact wording — the
-            # asserts pin the operator-recoverable signal only.
-            assert "stdout" in err
-            assert "regular file" in err
-            assert "pipe" in err
+            with caplog.at_level("WARNING"):
+                _warn_if_stdio_not_pipe(stdin_fd=r, stdout_fd=f.fileno())
+            assert "stdout" in caplog.text
+            assert "not a pipe" in caplog.text
         finally:
             f.close()
             os.close(r)
 
-    def test_regular_file_stdin_exits_with_friendly_message(
-        self, tmp_path, capsys
-    ):
-        """Symmetric case — stdin redirected from a regular file. Same
-        asyncio constraint applies via connect_read_pipe."""
-        from a2a_mcp_server import _assert_stdio_is_pipe_compatible
+    def test_regular_file_stdin_warns(self, tmp_path, caplog):
+        """Symmetric case — stdin redirected from a regular file."""
+        from a2a_mcp_server import _warn_if_stdio_not_pipe
 
         regular = tmp_path / "input.json"
         regular.write_bytes(b'{"jsonrpc":"2.0","id":1,"method":"initialize"}\n')
         f = open(regular, "rb")
         _r, w = os.pipe()
         try:
-            with pytest.raises(SystemExit) as excinfo:
-                _assert_stdio_is_pipe_compatible(
-                    stdin_fd=f.fileno(), stdout_fd=w
-                )
-            assert excinfo.value.code == 2
-            err = capsys.readouterr().err
-            assert "stdin" in err
-            assert "regular file" in err
+            with caplog.at_level("WARNING"):
+                _warn_if_stdio_not_pipe(stdin_fd=f.fileno(), stdout_fd=w)
+            assert "stdin" in caplog.text
+            assert "not a pipe" in caplog.text
         finally:
             f.close()
             os.close(w)
 
-    def test_closed_fd_exits_with_stat_error(self, capsys):
-        """If stdio is closed (rare but seen in detached daemonized
-        contexts), os.fstat raises OSError. We catch it and exit 2 with
-        a guidance message instead of letting the traceback escape."""
-        from a2a_mcp_server import _assert_stdio_is_pipe_compatible
+    def test_closed_fd_warns_about_stat_error(self, caplog):
+        """If stdio is closed, os.fstat raises OSError. Warning is
+        skipped silently (can't stat the fd)."""
+        from a2a_mcp_server import _warn_if_stdio_not_pipe
 
         r, w = os.pipe()
         os.close(w)  # Now `w` is a stale fd — fstat will fail.
         try:
-            with pytest.raises(SystemExit) as excinfo:
-                _assert_stdio_is_pipe_compatible(
-                    stdin_fd=r, stdout_fd=w
-                )
-            assert excinfo.value.code == 2
-            err = capsys.readouterr().err
-            assert "cannot stat stdout" in err
+            with caplog.at_level("WARNING"):
+                _warn_if_stdio_not_pipe(stdin_fd=r, stdout_fd=w)
+            # No warning emitted because fstat failed before the check
+            assert "not a pipe" not in caplog.text
         finally:
             os.close(r)