Create or return the napari viewer, with viewer detection.

When detect_only=True, reports available viewers (local and external) without creating or modifying anything.

Parameters

title : str, optional Optional window title (only for local viewer). width : int, optional Optional initial canvas width (only for local viewer). height : int, optional Optional initial canvas height (only for local viewer). port : int, optional If provided, attempt to connect to an external napari-mcp bridge on this port (default is taken from NAPARI_MCP_BRIDGE_PORT or 9999). detect_only : bool, default=False If True, only detect available viewers without initialising.

Close the viewer window and clear all layers.

Get comprehensive information about the current napari session.

Return a list of layers with key properties.

Get detailed info about a layer, optionally including data.

Always returns metadata (shape, dtype, scale, translate, type-specific properties). When include_data=True or slicing is provided, also returns statistics and/or raw data values.

Parameters

name : str Layer name (exact match). include_data : bool, default False If True, include data statistics (min/max/mean/std) and, for small layers, inline data values. slicing : str, optional Numpy-style index string, e.g. "0, :5, :5". Implies include_data=True. max_elements : int, default 1000 Maximum number of data elements to return inline. Larger data is stored and an output_id returned for read_output.

Add a layer to the viewer.

Parameters

layer_type : str One of: "image", "labels", "points", "shapes", "vectors", "tracks", "surface". path : str, optional File path (for image/labels). data : list, optional Inline data (coordinates, shape vertices, etc.). data_var : str, optional Name of a variable in the execute_code namespace. name : str, optional Layer name. Defaults to variable name or filename. colormap : str, optional Colormap name (image only). blending : str, optional Blending mode (image only). channel_axis : int, optional Channel axis (image only). size : float, optional Point size in pixels (points only, default 10). shape_type : str, optional Shape type: "rectangle", "ellipse", "line", "path", "polygon" (shapes only, default "rectangle"). edge_color : str, optional Edge color (shapes/vectors only). face_color : str, optional Face color (shapes only). edge_width : float, optional Edge width in pixels (shapes/vectors only).

Remove a layer by name.

Set properties on a layer by name.

Parameters

name : str Layer name (exact match). visible, opacity, colormap, blending, contrast_limits, gamma Standard layer rendering properties. new_name : str, optional Rename the layer. active : bool, optional If True, make this the selected/active layer. Setting to False has no effect (use viewer selection directly).

Reorder a layer by name.

Provide exactly one of:

• index: absolute target index

• before: move before this layer name

• after: move after this layer name

Apply property changes to multiple layers matching a filter.

Parameters

filter_type : str, optional Layer type name to match (e.g., "Image", "Labels", "Points"). filter_pattern : str, optional Glob pattern matched against layer names (e.g., "seg_*"). properties : dict, optional Properties to set on matched layers. Supported keys: visible, opacity, colormap, blending, contrast_limits, gamma, new_name (renames by appending a suffix is NOT supported — use set_layer_properties individually).

Configure viewer display: camera, dimensions, and grid.

All parameters are optional — set any combination in one call.

Parameters

reset_view : bool, default False If True, reset the camera to fit all data. center : list[float], optional Camera center position. zoom : float, optional Camera zoom factor (must be > 0). angles : list[float], optional Camera angles as [azimuth, elevation, roll] in degrees. ndisplay : int, optional Number of displayed dimensions (2 or 3). dims_axis : int, optional Axis index for slider position (use with dims_value). dims_value : int, optional Step value for the given axis. grid : bool, optional Enable or disable grid view.

Save a layer's data to a file.

Parameters

name : str Layer name. path : str Output file path. Format is inferred from extension unless format is specified. Supported: .tiff, .png, .npy, .csv (points/tabular only). format : str, optional Explicit format override (e.g., "npy", "tiff").

Take a screenshot, or a timelapse series by sweeping a dims axis.

For a single screenshot, call with no axis/slice_range. For a timelapse, provide both axis and slice_range.

Parameters

canvas_only : bool, default True If True, only capture the canvas area. save_path : str, optional Save single screenshot to this file path (returns metadata). axis : int, optional Dims axis to sweep for timelapse (e.g., temporal axis). slice_range : str, optional Python-like slice string, e.g. "1:5", ":6", "::2". Required when axis is provided. interpolate_to_fit : bool, default False If True, downsample timelapse frames to fit ~1.3 MB total. save_dir : str, optional Save timelapse frames as frame_NNNN.png in this directory.

Execute arbitrary Python code in the server's interpreter.

Similar to napari's console. The execution namespace persists across calls and includes 'viewer', 'napari', and 'np'.

Parameters

code : str Python code string. The value of the last expression (if any) is returned as 'result_repr'. line_limit : int, default=30 Maximum number of output lines to return. Use -1 for unlimited output. Warning: Using -1 may consume a large number of tokens.

Note

In standalone mode, code execution runs synchronously on the main thread (required for Qt/napari operations) and has no timeout. In bridge mode, a 600-second timeout is enforced.

Install Python packages using pip.

Parameters

packages : list of str List of package specifiers (e.g., "scikit-image", "torch==2.3.1"). upgrade : bool, optional If True, pass --upgrade flag. no_deps : bool, optional If True, pass --no-deps flag. index_url : str, optional Custom index URL. extra_index_url : str, optional Extra index URL. pre : bool, optional Allow pre-releases (--pre flag). line_limit : int, default=30 Maximum number of output lines to return. Use -1 for unlimited output. timeout : int, default=240 Timeout for pip install in seconds.

Read stored tool output with optional line range.

Parameters

output_id : str Unique ID of the stored output. start : int, default=0 Starting line number (0-indexed). end : int, default=-1 Ending line number (exclusive). If -1, read to end.