configured value for `{field_name}` is disallowed by require

Error message

configured value for `{field_name}` is disallowed by requirements ({err}); fallback to a requirement-compliant value also failed ({fallback_err})

What it means

Error "configured value for `{field_name}` is disallowed by requirements ({err}); fallback to a requirement-compliant value also failed ({fallback_err})" thrown in openai/codex.

Source

Thrown at codex-rs/core/src/config/mod.rs:2142

) -> std::io::Result<bool>
where
    T: Clone + std::fmt::Debug + Send + Sync,
{
    if let Err(err) = constrained_value.set(configured_value) {
        let fallback_value = constrained_value.get().clone();
        tracing::warn!(
            error = %err,
            ?fallback_value,
            requirement_source = ?constrained_value.source,
            "configured value is disallowed by requirements; falling back to required value for {field_name}"
        );
        let message = format!(
            "Configured value for `{field_name}` is disallowed by requirements; falling back to required value {fallback_value:?}. Details: {err}"
        );
        startup_warnings.push(message);

        constrained_value.set(fallback_value).map_err(|fallback_err| {
            std::io::Error::new(
                std::io::ErrorKind::InvalidInput,
                format!(
                    "configured value for `{field_name}` is disallowed by requirements ({err}); fallback to a requirement-compliant value also failed ({fallback_err})"
                ),
            )
        })?;
        return Ok(true);
    }

    Ok(false)
}

pub async fn load_global_mcp_servers(
    codex_home: &Path,
) -> std::io::Result<BTreeMap<String, McpServerConfig>> {
    // In general, Config::load_with_cli_overrides() should be used to load the
    // full config with requirements.toml applied, but in this case, we need
    // access to the raw TOML in order to warn the user about deprecated fields.

View on GitHub (pinned to 339751715c)

Solutions

Set `{field_name}` to a requirement-compliant value; check the governing requirements.

When it happens

Trigger: Thrown at codex-rs/core/src/config/mod.rs:2142 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/d9661adf65c0dbf1. Report an issue: GitHub.