WizTree MCP

日本語 | English

Disk-usage analysis over MCP. Windows uses WizTree CSV export; macOS uses a read-only native metadata scanner. Existing English/Japanese WizTree CSVs remain usable on both platforms. Scanned files are never modified.

Snapshot lifecycle — behavior change

Normal scans no longer create persistent snapshots on either platform. scan_path returns csvPath: "scan:<id>", an in-memory handle accepted by all CSV analysis tools. One scan is retained per process; the next successful scan replaces it, and a restart expires it. A failed scan leaves the previous handle available. Parsed user CSVs are cached separately (up to three).

On Windows, WizTree must export CSV. The server creates a unique temporary directory, waits for the exporter to exit, parses its CSV, reads any treemap PNG, and removes that temporary directory in finally, including exporter/parse failure, cancellation and timeout. Only the directory created by this operation is removed. Existing user CSVs and legacy exports/ are not automatically cleaned. Cleanup errors surface as failed calls. A hard process crash or power loss can prevent finally from running; no broad startup sweep deletes files.

On macOS, normal scanning writes no CSV at all. There are no generated timestamp or UUID filenames for persistent exports on either platform.

To intentionally retain a result (for example, the earlier side of a comparison), provide all three parameters:

{
  "targetPath": "/Users/you/Documents/example",
  "saveSnapshot": true,
  "snapshotDirectory": "/Users/you/Documents/chosen-snapshots",
  "snapshotName": "baseline.csv"
}

Use an absolute directory appropriate to the host; Windows accepts a path such as D:\chosen-snapshots. The filename must end in .csv and contain only letters, digits, dot, underscore or hyphen, with no path components. Existing files are never overwritten. A repeated baseline.csv request fails with EEXIST instead of silently creating another filename. Choose a new name only when you deliberately want another snapshot. Without saveSnapshot: true, providing a save destination is rejected.

Saved CSVs are limited to 32 MiB each; the direct regular files in the chosen directory plus the new CSV must fit 128 MiB. Saves are serialized within one server process. Avoid multiple server processes writing to the same directory. Files created by the save operation use mode 0600 where supported. Cancelled or failed writes remove only the new file opened by that operation. Windows saves preserve the original WizTree CSV; Mac saves use compatible English headers.

Compatibility changes: previous Windows scan_path calls returned a persistent timestamped CSV/PNG under exports/. They now return a memory handle unless explicit saving is requested. Treemap images are returned inline and their temporary PNGs are removed; no new persistent treemapPath is returned. Previously introduced Mac saveSnapshot: true without a directory/name is also rejected. Update clients that require durable filenames. Analysis output tables now show both logical and allocated size. Standalone CSV parsing is capped at 200,000 entries; scan parsing/traversal uses maxEntries (default 100,000, maximum 200,000).

Related MCP server: Disk Insights MCP

Tools

• locate_wiztree: Find WizTree from WIZTREE_PATH, PATH, and common locations.

• scan_path: Scan a specified target; return a memory handle or an explicitly named CSV. Windows supports its existing include/exclude filters, sorting, admin and treemap arguments.

• analyze_csv: Summarize a handle or an existing CSV.

• top_entries: Largest files/folders by logical or allocated size.

• drill_down: Direct children of a folder, sorted by size.

• search_entries: Path substring or glob search with matched count and size.

• old_large_files: Files larger than a threshold and older than a chosen age.

• extension_summary: File usage by extension.

• compare_csv: Growth/shrinkage between handles or CSV files.

• list_snapshots: List the configured legacy export directory. Intentionally saved snapshots elsewhere are accessed by their returned paths.

• get_treemap: Read a previously existing PNG from an explicit path.

• cleanup_snapshots: Legacy explicit deletion of older CSV/PNG files in the configured export directory. This tool does not establish ownership of legacy files; it is disabled in the configuration examples below.

Setting WIZTREE_MCP_DISABLE_CLEANUP=1 omits cleanup_snapshots from tools/list and rejects direct calls. Unset or other values preserve the legacy tool's availability. It is independent of cleanup of owned Windows temporary files, which always runs. No scan automatically removes user snapshots. WIZTREE_MCP_EXPORT_DIR controls only the legacy list/cleanup directory (default exports/ under the repository), not the explicit save destination.

List-style tools return compact tab-separated tables. csvPath inputs can be scan:<id> handles or filesystem paths. Save at least the earlier scan before running a second scan if you need a comparison.

Setup

Requires Node.js 22 or newer. Install without lifecycle scripts, then build:

npm ci --ignore-scripts
npm run typecheck
npm run build
npm test

Run node dist/index.js for stdio MCP. The process waits for JSON-RPC messages. No native dependencies or macOS WizTree installation are required.

Proposed MCP configuration

These are examples only; local configuration has not been changed.

macOS (adjust paths to your installation):

[mcp_servers.wiztree]
command = "/opt/homebrew/bin/node"
args = ["/path/to/wiztree-mcp/dist/index.js"]
startup_timeout_sec = 120

[mcp_servers.wiztree.env]
WIZTREE_MCP_DISABLE_CLEANUP = "1"

Windows:

[mcp_servers.wiztree]
command = 'node'
args = ['C:\path\to\wiztree-mcp\dist\index.js']
startup_timeout_sec = 120

[mcp_servers.wiztree.env]
WIZTREE_PATH = 'C:\Program Files\WizTree\WizTree64.exe'
WIZTREE_MCP_DISABLE_CLEANUP = '1'

WIZTREE_PATH is optional when WizTree is found in a common location or PATH. admin: true still triggers Windows UAC. The exporter process is terminated on cancellation/timeout and awaited before temporary-file cleanup. Windows process termination, UAC and file-lock behavior require real Windows validation.

No allowed-root setting is implemented. The server can scan any directory readable by its process. Mac rejects / and symlink targets, but that is not an allowlist. CSV analysis and PNG reading also accept arbitrary readable paths; explicit saves can target arbitrary writable directories. Register only after agreeing on that scope or implementing the desired allowed-root policy.

macOS backend

Only metadata is read, never file contents. includeFiles / includeFolders control returned rows; directory totals still include all encountered regular files. POSIX drilldown/comparison paths preserve case.

• Symlinks and nested mounts are skipped. Symlink target directories and / are rejected. Canonical containment is rechecked before listing. Node path APIs leave a check/list race against concurrent adversarial path replacement; scan a stable trusted directory.

• Permission and disappearing-file errors produce partial: true, errorCount and up to 100 error details. Skipped link/mount counts are separate.

• Cancellation, timeout (default 300 seconds), traversal queue and entry limits abort without publishing a result. Pending filesystem calls finish before cancellation is observed.

• Logical size is st_size; allocated size is st_blocks * 512. Hardlinks count once per path and are reported as hardlinkEntries. APFS clones/shared extents, compression, snapshots, purgeable storage and actual reclaimable bytes are not reconciled. Totals exclude directory metadata and special files.

• WizTree-specific admin, filters, sorting, executable path and treemap options are rejected on Mac. Use the analysis tools to filter and sort results.

Privacy

Results and saved CSVs include full local paths. Check outputs before sharing. Explicitly saved files outside the repository are not covered by its Git ignore rules. Normal scans create no persistent CSV/PNG exports.

Implementation / validation

Added native scanning, Windows temporary-export lifecycle, shared named snapshot saves, in-memory handles, optional cleanup-tool disablement and fixture tests. Direct dependency declarations and package names are unchanged; patched transitive versions are recorded in the lockfile without adding native packages.

npm run typecheck, npm run build, npm test (16 tests) and git diff --check pass. Tests cover native sizes, symlinks, hardlinks, permission errors, cancellation and limits; English/Japanese Windows CSV compatibility; Mac real stdio analysis; cleanup-disabled tools/list; explicit saves, duplicate refusal and size budgets; and Windows mock/Node fixture subprocess export success, failure, parser failure, cancellation and timeout, including owned-temp cleanup and user-CSV preservation. The Windows lifecycle tests run on Mac. No real Windows/WizTree/UAC/taskkill run was performed. Tests use small temporary fixtures removed after execution (the 128 MiB budget fixture is sparse).

Validation used only fixtures; no real disk scan, user-data deletion, MCP registration or persistent permission expansion was performed.

Dependency audit follow-up

npm audit --audit-level=high passes after compatible transitive updates; the existing CI threshold is unchanged. No forced or major update was used, and installed versions were checked against the lockfile after npm ci --ignore-scripts.

The compatible qs update also patches existing side-channel 1.1.0 → 1.1.1; esbuild's existing platform packages follow 0.28.2. No package names were added. Two findings remain: csv-parse requires a major update and body-parser 2.3.0 introduces a nested content-type 2.x dependency. Both are deferred for separate review. This is not a zero-findings audit report. No audit exception was added.

License

MIT. See LICENSE.