list_rois
Retrieve all regions of interest saved in the current MilliMap session.
Instructions
List all ROIs saved in the current MilliMap session.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Implementation Reference
- src/millimap_mcp/server.py:219-222 (handler)The `list_rois` tool handler: decorated with @mcp.tool(), calls _load_snapshot() to read the MCP session file and returns the 'rois' array formatted as JSON via _fmt_json().
@mcp.tool() def list_rois() -> str: """List all ROIs saved in the current MilliMap session.""" return _fmt_json(_load_snapshot().get("rois", [])) - src/millimap_mcp/server.py:219-222 (registration)The `list_rois` tool is registered via the `@mcp.tool()` decorator on the `FastMCP` instance named `mcp`, defined at line 22.
@mcp.tool() def list_rois() -> str: """List all ROIs saved in the current MilliMap session.""" return _fmt_json(_load_snapshot().get("rois", [])) - src/millimap_mcp/server.py:61-74 (helper)The `_load_snapshot()` helper reads the MCP session JSON file (at ~/.millimap/mcp_session.json) and returns its contents as a dict. This is what `list_rois` calls to get the 'rois' array.
def _load_snapshot() -> dict[str, Any]: if not SNAPSHOT_PATH.exists(): return { "error": "no_snapshot", "message": ( f"No MilliMap snapshot found at {SNAPSHOT_PATH}. " "Is MilliMap running with a dataset loaded?" ), } try: with SNAPSHOT_PATH.open("r") as f: return json.load(f) except Exception as exc: return {"error": "read_failed", "message": str(exc)} - src/millimap_mcp/server.py:77-78 (helper)The `_fmt_json()` helper serializes a Python object to an indented JSON string, used to format the output of `list_rois`.
def _fmt_json(payload: Any) -> str: return json.dumps(payload, indent=2, default=str) - src/millimap_mcp/server.py:219-222 (schema)The `list_rois` tool takes no arguments (no input schema) and returns a string (JSON output). The shape comes from the snapshot's 'rois' key which is an array.
@mcp.tool() def list_rois() -> str: """List all ROIs saved in the current MilliMap session.""" return _fmt_json(_load_snapshot().get("rois", []))