openai/codex · error · anyhow::Error

network.mitm_hooks[{hook_index}].match.body is reserved for

Error message

network.mitm_hooks[{hook_index}].match.body is reserved for a future release and is not yet supported

What it means

The codex network proxy deserializes network.mitm_hooks[i].match.body (MitmHookBodyConfig accepts arbitrary TOML values), but body matching is not implemented in this release. validate_mitm_hook_config rejects any hook whose match table contains a body key, so the config parses successfully yet fails at proxy startup or test time with this reserved-for-future-release message.

Source

Thrown at codex-rs/network-proxy/src/mitm_hook.rs:206

        if methods.is_empty() {
            return Err(anyhow!(
                "network.mitm_hooks[{hook_index}].match.methods must not be empty"
            ));
        }

        let path_prefixes =
            compile_path_matchers(&hook.matcher.path_prefixes).with_context(|| {
                format!("invalid network.mitm_hooks[{hook_index}].match.path_prefixes")
            })?;
        if path_prefixes.is_empty() {
            return Err(anyhow!(
                "network.mitm_hooks[{hook_index}].match.path_prefixes must not be empty"
            ));
        }

        if let Some(body) = hook.matcher.body.as_ref() {
            let _ = body;
            return Err(anyhow!(
                "network.mitm_hooks[{hook_index}].match.body is reserved for a future release and is not yet supported"
            ));
        }

        validate_query_constraints(&hook.matcher.query)
            .with_context(|| format!("invalid network.mitm_hooks[{hook_index}].match.query"))?;
        validate_header_constraints(&hook.matcher.headers)
            .with_context(|| format!("invalid network.mitm_hooks[{hook_index}].match.headers"))?;
        validate_strip_request_headers(&hook.actions.strip_request_headers).with_context(|| {
            format!("invalid network.mitm_hooks[{hook_index}].actions.strip_request_headers")
        })?;
        validate_injected_headers(&hook.actions.inject_request_headers).with_context(|| {
            format!("invalid network.mitm_hooks[{hook_index}].actions.inject_request_headers")
        })?;

        if host.is_empty() {
            return Err(anyhow!(
                "network.mitm_hooks[{hook_index}].host must not be empty"

View on GitHub (pinned to 339751715c)

Solutions

1. Delete the body key (and its table) from every hook's match section
2. Express the matching you need with supported matchers: methods, path_prefixes (including pattern: globs), query, and headers
3. If body matching is required, check the codex release notes for the version that enables it before re-adding the key

Example fix

# before — config.toml
[[network.mitm_hooks]]
host = "api.example.com"
[network.mitm_hooks.match]
methods = ["POST"]
path_prefixes = ["/v1/"]
body = {contains = "draft"}

# after
[[network.mitm_hooks]]
host = "api.example.com"
[network.mitm_hooks.match]
methods = ["POST"]
path_prefixes = ["/v1/"]

// Rust — reject before compiling hooks
for (i, hook) in config.mitm_hooks.iter().enumerate() {
    if hook.matcher.body.is_some() {
        return Err(anyhow!("network.mitm_hooks[{i}].match.body is unsupported in this release"));
    }
}

fn hook_has_no_body(hook: &MitmHookConfig) -> bool {
    hook.matcher.body.is_none()
}

match compile_mitm_hooks(&config) {
    Ok(_) => {}
    Err(err) => eprintln!("{err:#}"), // chain shows 'network.mitm_hooks[0].match.body is reserved ...'
}

When it happens

Trigger: Any [[network.mitm_hooks]] entry whose match table sets body to any value — body = {contains = "draft"} or even an empty body = {} table — when validate_mitm_hook_config runs, or when compile_mitm_hooks_with_resolvers runs since it calls that validator first.

Common situations: Copying hook config from newer docs, a future release's examples, or another team's setup into an older binary; writing config ahead of the API; upgrading/downgrading codex versions where the field exists in the schema but the matcher is still gated.

Related errors

• network.mitm_hooks[{hook_index}].host must not be empty
• expected exactly one of secret_env_var or secret_file
• path_prefixes must not contain empty entries
• glob pattern must not be empty
• invalid glob pattern {pattern:?}: {err}

AI-assisted analysis of openai/codex@339751715c (2026-08-25). Data as JSON: /api/errors/fbc9167a88328a3d. Report an issue: GitHub.