Install/uninstall can overwrite Codex config when config parsing fails

[abhinavkr26104]

Bug

codex-supermemory install / uninstall can silently overwrite a user’s existing Codex configuration when config parsing fails.

Problem

In src/cli.ts, mergeConfigToml catches TOML parse failures and falls back to an empty object:

try {
  existing = TOML.parse(readFileSync(CONFIG_FILE, "utf-8")) as Record<string, unknown>;
} catch {
  existing = {};
}

The command then writes the merged config back to ~/.codex/config.toml.

A similar pattern exists for hooks.json, where parsing failures fall back to a default empty hook structure before writing the file again.

This means a user with a pre-existing config file containing a syntax error can lose their existing configuration after running install or uninstall.

Reproduction

1. Create a pre-existing Codex config with a TOML syntax error:

# ~/.codex/config.toml
model = "gpt-5"
[features
web_search = true

2. Run:

codex-supermemory uninstall

or:

codex-supermemory install

Actual Behavior

The command silently treats the unreadable config as empty and rewrites ~/.codex/config.toml with a minimal/modified configuration.

This can erase unrelated user settings.

Expected Behavior

If an existing config file cannot be parsed, install/uninstall should not overwrite it.

Instead, it should either:

• Abort with a clear parse error and leave the original file untouched, or
• Create a backup before writing a replacement

The safer default is to abort and tell the user which file could not be parsed.

Affected Areas

• src/cli.ts
• mergeConfigToml
• Hooks config handling around hooks.json

Suggested Fix

When parsing an existing config file fails:

• Surface a clear error message
• Exit non-zero
• Do not write back to the original file

For example:

Failed to parse ~/.codex/config.toml. Please fix the syntax error before running install/uninstall.

Apply the same behavior to hooks.json parsing failures.

Impact

This is a data-loss risk because install/uninstall may erase unrelated Codex configuration that belongs to the user.