# Path lexical parse

`path-lexical-parse` · version 1.0.0 · File paths (lexical) · free, no key needed

Decompose a file path into its lexical components without accessing the filesystem.

**Use when you need to: path lexical parse · parse file path · path decomposition.**

## Supported

- path lexical parse
- parse file path
- path decomposition
- file path components
- path stem extension

## Not supported

- stat file
- resolve symlinks
- filesystem access
- real path resolution

## Behavior

- Detect format from path string unless explicit format is provided.
- Windows detection: drive letter (C:), UNC (\\server\share), or backslash without forward slash.
- ext includes the leading dot; stem is base without ext.
- If base starts with "." and has no other dot, stem=base, ext="".
- segments are normalized (no "." or ".." retained).
- Empty string path is rejected (min length 1 byte).
- Paths exceeding 4096 bytes are rejected.

## Input

- `path` (string, required): min length 1; max length 4096
- `format` (one of "posix", "windows", "auto", optional)

## Output

- `format` (one of "posix", "windows", required)
- `root` (string, required)
- `dir` (string, required)
- `base` (string, required)
- `stem` (string, required)
- `ext` (string, required)
- `drive` (string or null, required)
- `is_unc` (boolean, required)
- `is_absolute` (boolean, required)
- `segments` (array of string, required)

## Limits

- max path bytes: 4096
- max segments: 1024

## Example

Request input:

```json
{
  "path": "/usr/local/bin/node"
}
```

Response:

```json
{
  "result": {
    "format": "posix",
    "root": "/",
    "dir": "/usr/local/bin",
    "base": "node",
    "stem": "node",
    "ext": "",
    "drive": null,
    "is_unc": false,
    "is_absolute": true,
    "segments": [
      "usr",
      "local",
      "bin",
      "node"
    ]
  }
}
```

## How to call it

### MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "path-lexical-parse",
  "version": "1.0.0",
  "input": {
    "path": "/usr/local/bin/node"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/path-lexical-parse/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"path":"/usr/local/bin/node"}'
```

The machine-readable contract is at [/v1/tools/path-lexical-parse/versions/1.0.0](/v1/tools/path-lexical-parse/versions/1.0.0).

### CLI

```sh
node cli.mjs run path-lexical-parse 1.0.0 --input input.json --base-url https://computefirst.net
```

Get the client at [/clients/cli/](/clients/cli/).

## Related tools

- [Path lexical normalize](/tools/path-lexical-normalize): Normalize a path lexically: collapse redundant separators, resolve "." and ".." segments.
- [Path set classify](/tools/path-set-classify): Classify an array of file paths by file extension, depth histogram, and path format.
- [Path lexical common ancestor](/tools/path-lexical-common-ancestor): Compute the deepest common ancestor directory of a set of paths.
- [Path lexical contains](/tools/path-lexical-contains): Check whether a child path is lexically inside a parent directory.
- [Path lexical join](/tools/path-lexical-join): Join an array of path segments lexically, resolving absolute reset boundaries and normalizing separators.
- [Path lexical relative](/tools/path-lexical-relative): Compute the lexical relative path from one path to another without filesystem access.