openai/codex · error

{LABEL} uses a reserved namespace: {namespace}

Error message

{LABEL} uses a reserved namespace: {namespace}

What it means

Error "{LABEL} uses a reserved namespace: {namespace}" thrown in openai/codex.

Source

Thrown at codex-rs/core/src/config/mod.rs:3093

        .bytes()
        .all(|byte| byte.is_ascii_alphanumeric() || matches!(byte, b'_' | b'-'))
    {
        return Err(std::io::Error::new(
            std::io::ErrorKind::InvalidInput,
            format!("{LABEL} must match ^[a-zA-Z0-9_-]+$"),
        ));
    }
    if namespace.chars().count() > MAX_LEN {
        return Err(std::io::Error::new(
            std::io::ErrorKind::InvalidInput,
            format!("{LABEL} must be at most {MAX_LEN} characters"),
        ));
    }
    if namespace == "mcp"
        || namespace.starts_with("mcp__")
        || RESERVED_RESPONSES_NAMESPACES.contains(&namespace)
    {
        return Err(std::io::Error::new(
            std::io::ErrorKind::InvalidInput,
            format!("{LABEL} uses a reserved namespace: {namespace}"),
        ));
    }

    Ok(())
}

impl Config {
    #[cfg(test)]
    async fn load_from_base_config_with_overrides(
        cfg: ConfigToml,
        overrides: ConfigOverrides,
        codex_home: AbsolutePathBuf,
    ) -> std::io::Result<Self> {
        // Note this ignores requirements.toml enforcement for tests.
        let config_layer_stack = ConfigLayerStack::default();
        Self::load_config_with_layer_stack(

View on GitHub (pinned to 339751715c)

Solutions

1. Choose a name for {LABEL} outside the reserved namespace {namespace}.

When it happens

Trigger: Thrown at codex-rs/core/src/config/mod.rs:3093 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of openai/codex@339751715c (2026-08-25). Data as JSON: /api/errors/797fdd560cd0b11b. Report an issue: GitHub.