Merge pull request #6 from Molecule-AI/fix/507-mcp-server-path-absolute-imports

fix: resolve MCP server path from package + absolute imports (2nd half of #507)

molecule_runtime/a2a_client.py

@@ -10,7 +10,7 @@ import uuid
 
 import httpx
 
-from platform_auth import auth_headers
+from molecule_runtime.platform_auth import auth_headers
 
 logger = logging.getLogger(__name__)
 

molecule_runtime/a2a_mcp_server.py

@@ -17,7 +17,23 @@ import json
 import logging
 import sys
 
-from a2a_tools import (
+# Absolute imports so the installed-package location works too. Previously
+# the script relied on `/app` being on sys.path (legacy template layout),
+# which broke silently when the current template dropped that copy —
+# claude-code then initialised with zero MCP tools and every agent
+# reported "search_memory / commit_memory / list_peers / delegate_task
+# not available" (second half of #507). The /app launch path is still
+# supported via a sys.path shim below for anyone running the script
+# with `python /app/a2a_mcp_server.py`.
+import os as _os
+if __package__ in (None, ""):
+    # Running as a script (python path/to/a2a_mcp_server.py) — put the
+    # package root on sys.path so the absolute imports below resolve.
+    _pkg_root = _os.path.dirname(_os.path.dirname(_os.path.abspath(__file__)))
+    if _pkg_root not in sys.path:
+        sys.path.insert(0, _pkg_root)
+
+from molecule_runtime.a2a_tools import (
     tool_check_task_status,
     tool_commit_memory,
     tool_delegate_task,
@@ -32,7 +48,7 @@ logger = logging.getLogger(__name__)
 
 # Re-export constants and client functions so existing imports
 # (e.g. tests that do `import a2a_mcp_server`) still work.
-from a2a_client import (  # noqa: F401, E402
+from molecule_runtime.a2a_client import (  # noqa: F401, E402
     PLATFORM_URL,
     WORKSPACE_ID,
     _A2A_ERROR_PREFIX,
@@ -42,7 +58,7 @@ from a2a_client import (  # noqa: F401, E402
     get_workspace_info,
     send_a2a_message,
 )
-from a2a_tools import report_activity  # noqa: F401, E402
+from molecule_runtime.a2a_tools import report_activity  # noqa: F401, E402
 
 # --- Tool definitions (schemas) ---
 

molecule_runtime/a2a_tools.py

@@ -8,7 +8,7 @@ import uuid
 
 import httpx
 
-from a2a_client import (
+from molecule_runtime.a2a_client import (
     PLATFORM_URL,
     WORKSPACE_ID,
     _A2A_ERROR_PREFIX,
@@ -24,7 +24,7 @@ def _auth_headers_for_heartbeat() -> dict[str, str]:
     """Return Phase 30.1 auth headers; tolerate platform_auth being absent
     in older installs (e.g. during rolling upgrade)."""
     try:
-        from platform_auth import auth_headers
+        from molecule_runtime.platform_auth import auth_headers
         return auth_headers()
     except Exception:
         return {}

molecule_runtime/consolidation.py

@@ -14,7 +14,7 @@ import os
 
 import httpx
 
-from platform_auth import auth_headers
+from molecule_runtime.platform_auth import auth_headers
 
 logger = logging.getLogger(__name__)
 

molecule_runtime/executor_helpers.py

@@ -36,7 +36,10 @@ logger = logging.getLogger(__name__)
 
 WORKSPACE_MOUNT = "/workspace"
 CONFIG_MOUNT = "/configs"
-DEFAULT_MCP_SERVER_PATH = "/app/a2a_mcp_server.py"
+# Legacy template layout copied a2a_mcp_server.py into /app. Current
+# templates don't — the script lives inside the installed runtime package.
+# Kept as a last-resort fallback only.
+LEGACY_MCP_SERVER_PATH = "/app/a2a_mcp_server.py"
 DEFAULT_DELEGATION_RESULTS_FILE = "/tmp/delegation_results.jsonl"
 PLATFORM_HTTP_TIMEOUT_S = 5.0
 MEMORY_RECALL_LIMIT = 10
@@ -44,12 +47,38 @@ MEMORY_CONTENT_MAX_CHARS = 200
 BRIEF_SUMMARY_MAX_LEN = 80
 
 
+def _default_mcp_server_path() -> str:
+    """Resolve the installed ``a2a_mcp_server.py`` path from the package.
+
+    Fix for the secondary half of #507: when agents started producing text
+    again (after the CRLF hook fix), the a2a MCP server failed to start
+    because the hard-coded ``/app/a2a_mcp_server.py`` doesn't exist in the
+    current workspace-template image — the template's Dockerfile copies
+    ``adapter.py`` into /app but not the MCP server script. claude-code
+    then initialised with zero MCP tools, so every agent reported
+    "search_memory / commit_memory / list_peers / delegate_task not
+    available" on the first post-fix pulse.
+
+    Resolve the path from the package itself so it always points at the
+    real installed script, regardless of which template layout imported
+    the runtime. Legacy /app/ path kept only as last-resort fallback.
+    """
+    try:
+        from molecule_runtime import a2a_mcp_server as _mcp_mod
+        path = getattr(_mcp_mod, "__file__", None)
+        if path and os.path.isfile(path):
+            return path
+    except Exception:
+        pass
+    return LEGACY_MCP_SERVER_PATH
+
+
 def get_mcp_server_path() -> str:
     """Return the path to the stdio MCP server script.
 
     Overridable via A2A_MCP_SERVER_PATH for tests and non-default layouts.
     """
-    return os.environ.get("A2A_MCP_SERVER_PATH", DEFAULT_MCP_SERVER_PATH)
+    return os.environ.get("A2A_MCP_SERVER_PATH", _default_mcp_server_path())
 
 
 # ========================================================================

molecule_runtime/heartbeat.py

@@ -17,7 +17,7 @@ from pathlib import Path
 
 import httpx
 
-from platform_auth import auth_headers
+from molecule_runtime.platform_auth import auth_headers
 
 logger = logging.getLogger(__name__)
 

molecule_runtime/main.py

@@ -39,7 +39,7 @@ from initial_prompt import (
     mark_initial_prompt_attempted,
     resolve_initial_prompt_marker,
 )
-from platform_auth import auth_headers
+from molecule_runtime.platform_auth import auth_headers
 
 
 def get_machine_ip() -> str:  # pragma: no cover