`pyproject.toml` is not a supported output format for `{}` (

Error message

`pyproject.toml` is not a supported output format for `{}` (supported formats: {})

What it means

Error "`pyproject.toml` is not a supported output format for `{}` (supported formats: {})" thrown in astral-sh/uv.

Source

Thrown at crates/uv/src/commands/project/export.rs:326

                }
            }
        }
        ExportTarget::Script(script) => InstallTarget::Script {
            script,
            lock: &lock,
        },
    };

    // Validate that the set of requested extras and development groups are defined in the lockfile.
    target.validate_extras(&extras)?;
    target.validate_groups(&groups)?;

    if output_file
        .as_deref()
        .and_then(Path::file_name)
        .is_some_and(|name| name.eq_ignore_ascii_case("pyproject.toml"))
    {
        return Err(anyhow!(
            "`pyproject.toml` is not a supported output format for `{}` (supported formats: {})",
            "uv export".green(),
            ExportFormat::value_variants()
                .iter()
                .filter_map(clap::ValueEnum::to_possible_value)
                .map(|value| value.get_name().to_string())
                .join(", ")
        ));
    }

    // Write the resolved dependencies to the output channel.
    let mut writer = OutputWriter::new(!quiet || output_file.is_none(), output_file.as_deref());

    // Determine the output format.
    let format = format.unwrap_or_else(|| {
        if output_file
            .as_deref()
            .and_then(Path::extension)

View on GitHub (pinned to f1a42680ff)

When it happens

Trigger: Thrown at crates/uv/src/commands/project/export.rs:326 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of astral-sh/uv@f1a42680ff (2026-08-16). Data as JSON: /api/errors/2fdf5f4dda7c790e. Report an issue: GitHub.