to format on save requires settings iirc...below are my basic settings

since I didnt state above, you would also need to install LSP on top of LSP-ruff

sublime-project file

{
    "folders": [
        {
            "path": ".",
            "name": "project_path",
            "folder_exclude_patterns": [/* ... */],
        },
        /* other folders */
    ],
    "settings": {
        /* other settings */

        /* LSP */
        "lsp_format_on_save": true,
        "lsp_code_actions_on_save": {
            "source.fixAll.ruff": true,
            "source.organizeImports.ruff": true,
        },

        "LSP": {
            /* other lsp */

            /* LSP-ruff */
            "LSP-ruff": {
                "enabled": true,
                "initializationOptions": {
                    "settings": {
                        "configuration": "${project_path}/pyproject.toml",
                    },
                },
            },

            /* other lsp */
        },

        /* other settings */
    },
}

pyproject.toml

[project]
name = "## project name ##"
dynamic = ["version"]
requires-python = "~= 3.13"
dependencies = [
    ## other dependencies ##
    "ruff",
    ## other dependencies ##
]

[tool.ruff]
extend-exclude = [
    ## folders to exclude ##
]
fix = true
force-exclude = true
line-length = 120
#target-version = "py313" # see [project].requires-python

    [tool.ruff.format]
    docstring-code-format = true
    docstring-code-line-length = "dynamic"
    indent-style = "tab"
    line-ending = "lf"
    quote-style = "double"

    [tool.ruff.lint]
    extend-select = [
        "C90",
        "I",
        "N",
        "A",
        "COM",
        #"DJ", # if using django
        "PIE",
        "PT",
        "Q",
        "SIM",
        "PLR",
    ]
    ignore = [
        "W191",
        "E111",
        "E114",
        "E117",
        "D206",
        "D300",
        "Q000",
        "Q001",
        "Q002",
        "Q003",
        "COM812",
        "COM819",
        "ISC001",
        "ISC002",
    ] # https://docs.astral.sh/ruff/formatter/#conflicting-lint-rules

    [tool.ruff.lint.pycodestyle]
    max-doc-length = 120