feat(mcp): add basic_memory_diagnostics tool for version and system info

Adds a new read-only MCP tool `basic_memory_diagnostics` that surfaces:
- Basic Memory package version and API version (from __init__.py)
- Python version and platform/architecture details
- Config file path and full config.json contents (cloud_api_key redacted)

Resolves #187.

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Drew Cain <groksrc@gmail.com>

src/basic_memory/mcp/tools/__init__.py

@@ -36,7 +36,11 @@ from basic_memory.mcp.tools.chatgpt_tools import search, fetch
 # Schema tools
 from basic_memory.mcp.tools.schema import schema_validate, schema_infer, schema_diff
 
+# Diagnostics tool
+from basic_memory.mcp.tools.basic_memory_diagnostics import basic_memory_diagnostics
+
 __all__ = [
+    "basic_memory_diagnostics",
     "build_context",
     "canvas",
     "cloud_info",

src/basic_memory/mcp/tools/basic_memory_diagnostics.py

@@ -0,0 +1,84 @@
+"""Diagnostic tool for Basic Memory version and system information."""
+
+import json
+import platform
+import sys
+
+import basic_memory
+from basic_memory.config import CONFIG_FILE_NAME, ConfigManager
+from basic_memory.mcp.server import mcp
+
+# Fields in BasicMemoryConfig that contain secrets and must never be surfaced.
+_SECRET_FIELDS = frozenset({"cloud_api_key"})
+
+
+def _redact_config(raw: dict) -> dict:
+    """Return a copy of the raw config dict with secret fields removed.
+
+    Only top-level keys are redacted. Nested secret-looking keys within
+    project entries are not currently present, but the pattern is explicit
+    so it is easy to extend.
+    """
+    return {k: v for k, v in raw.items() if k not in _SECRET_FIELDS}
+
+
+@mcp.tool(
+    "basic_memory_diagnostics",
+    annotations={"readOnlyHint": True, "openWorldHint": False},
+)
+def basic_memory_diagnostics() -> str:
+    """Return version, system, and configuration diagnostics for Basic Memory.
+
+    Provides:
+    - Basic Memory package version and API version
+    - Python version and platform details
+    - Config file path and its contents (secrets redacted)
+
+    Useful for troubleshooting installations and gathering information for
+    support requests. Read-only; never emits secrets or API keys.
+    """
+    # --- Version information ---
+    bm_version = basic_memory.__version__
+    api_version = basic_memory.__api_version__
+
+    # --- System information ---
+    python_version = sys.version
+    platform_info = platform.platform()
+    machine = platform.machine()
+
+    # --- Configuration ---
+    manager = ConfigManager()
+    config_file = manager.config_dir / CONFIG_FILE_NAME
+    config_exists = config_file.exists()
+
+    if config_exists:
+        try:
+            raw_config = json.loads(config_file.read_text(encoding="utf-8"))
+            safe_config = _redact_config(raw_config)
+            config_dump = json.dumps(safe_config, indent=2, default=str)
+        except Exception as exc:  # pragma: no cover
+            config_dump = f"<error reading config: {exc}>"
+    else:
+        config_dump = "<config file not found>"
+
+    lines = [
+        "# Basic Memory Diagnostics",
+        "",
+        "## Version",
+        f"- basic-memory: {bm_version}",
+        f"- API version: {api_version}",
+        "",
+        "## System",
+        f"- Python: {python_version}",
+        f"- Platform: {platform_info}",
+        f"- Architecture: {machine}",
+        "",
+        "## Configuration",
+        f"- Config path: {config_file}",
+        f"- Config exists: {config_exists}",
+        "",
+        "```json",
+        config_dump,
+        "```",
+    ]
+    return "\n".join(lines)

tests/mcp/test_tool_basic_memory_diagnostics.py

@@ -0,0 +1,146 @@
+"""Tests for the basic_memory_diagnostics MCP tool."""
+
+import json
+import platform
+import sys
+from unittest.mock import MagicMock, patch
+
+import basic_memory
+from basic_memory.mcp.tools.basic_memory_diagnostics import (
+    _redact_config,
+    basic_memory_diagnostics,
+)
+
+
+# ---------------------------------------------------------------------------
+# Unit tests for _redact_config helper
+# ---------------------------------------------------------------------------
+
+
+def test_redact_config_removes_cloud_api_key():
+    raw = {"cloud_api_key": "bmc_secret", "default_project": "main", "projects": {}}
+    result = _redact_config(raw)
+    assert "cloud_api_key" not in result
+    assert result["default_project"] == "main"
+    assert "projects" in result
+
+
+def test_redact_config_passes_through_safe_fields():
+    raw = {"default_project": "main", "log_level": "INFO", "env": "dev"}
+    result = _redact_config(raw)
+    assert result == raw
+
+
+def test_redact_config_empty_dict():
+    assert _redact_config({}) == {}
+
+
+# ---------------------------------------------------------------------------
+# Tests for the basic_memory_diagnostics tool
+# ---------------------------------------------------------------------------
+
+
+def test_diagnostics_returns_string():
+    result = basic_memory_diagnostics()
+    assert isinstance(result, str)
+
+
+def test_diagnostics_includes_version():
+    result = basic_memory_diagnostics()
+    assert basic_memory.__version__ in result
+    assert basic_memory.__api_version__ in result
+
+
+def test_diagnostics_includes_python_version():
+    result = basic_memory_diagnostics()
+    # sys.version can be multi-line; just check the version tuple prefix
+    major_minor = f"{sys.version_info.major}.{sys.version_info.minor}"
+    assert major_minor in result
+
+
+def test_diagnostics_includes_platform():
+    result = basic_memory_diagnostics()
+    assert platform.machine() in result
+
+
+def test_diagnostics_includes_config_path(tmp_path):
+    """Config path section should appear in output."""
+    with patch("basic_memory.mcp.tools.basic_memory_diagnostics.ConfigManager") as MockMgr:
+        mock_mgr = MagicMock()
+        mock_mgr.config_dir = tmp_path
+        MockMgr.return_value = mock_mgr
+
+        config_file = tmp_path / "config.json"
+        config_file.write_text(json.dumps({"default_project": "main", "projects": {}}))
+
+        result = basic_memory_diagnostics()
+
+    assert str(tmp_path) in result
+    assert "Config path:" in result
+
+
+def test_diagnostics_config_exists_with_valid_json(tmp_path):
+    """When config file exists, its safe contents should appear as JSON."""
+    config_data = {
+        "default_project": "research",
+        "projects": {"research": {"path": str(tmp_path / "research")}},
+    }
+    with patch("basic_memory.mcp.tools.basic_memory_diagnostics.ConfigManager") as MockMgr:
+        mock_mgr = MagicMock()
+        mock_mgr.config_dir = tmp_path
+        MockMgr.return_value = mock_mgr
+
+        config_file = tmp_path / "config.json"
+        config_file.write_text(json.dumps(config_data))
+
+        result = basic_memory_diagnostics()
+
+    assert "research" in result
+    assert "```json" in result
+
+
+def test_diagnostics_redacts_cloud_api_key(tmp_path):
+    """cloud_api_key must never appear in diagnostic output."""
+    config_data = {
+        "default_project": "main",
+        "cloud_api_key": "bmc_super_secret_token",
+        "projects": {},
+    }
+    with patch("basic_memory.mcp.tools.basic_memory_diagnostics.ConfigManager") as MockMgr:
+        mock_mgr = MagicMock()
+        mock_mgr.config_dir = tmp_path
+        MockMgr.return_value = mock_mgr
+
+        config_file = tmp_path / "config.json"
+        config_file.write_text(json.dumps(config_data))
+
+        result = basic_memory_diagnostics()
+
+    assert "bmc_super_secret_token" not in result
+    assert "cloud_api_key" not in result
+
+
+def test_diagnostics_config_missing(tmp_path):
+    """When config file does not exist, output should say so."""
+    with patch("basic_memory.mcp.tools.basic_memory_diagnostics.ConfigManager") as MockMgr:
+        mock_mgr = MagicMock()
+        mock_mgr.config_dir = tmp_path
+        MockMgr.return_value = mock_mgr
+
+        # Ensure no config.json is present
+        config_file = tmp_path / "config.json"
+        assert not config_file.exists()
+
+        result = basic_memory_diagnostics()
+
+    assert "Config exists: False" in result
+    assert "<config file not found>" in result
+
+
+def test_diagnostics_output_sections():
+    """All expected section headers should be present."""
+    result = basic_memory_diagnostics()
+    assert "# Basic Memory Diagnostics" in result
+    assert "## Version" in result
+    assert "## System" in result
+    assert "## Configuration" in result