[codex] Add marketplace remove command and shared logic (#17752)

## Summary

Move the marketplace remove implementation into shared core logic so
both the CLI command and follow-up app-server RPC can reuse the same
behavior.

This change:
- adds a shared `codex_core::plugins::remove_marketplace(...)` flow
- moves validation, config removal, and installed-root deletion out of
the CLI
- keeps the CLI as a thin wrapper over the shared implementation
- adds focused core coverage for the shared remove path

## Validation

- `just fmt`
- focused local coverage for the shared remove path
- heavier follow-up validation deferred to stacked PR CI

codex-rs/config/src/lib.rs

@@ -63,7 +63,10 @@ pub use diagnostics::format_config_error_with_source;
 pub use diagnostics::io_error_from_config_error;
 pub use fingerprint::version_for_toml;
 pub use marketplace_edit::MarketplaceConfigUpdate;
+pub use marketplace_edit::RemoveMarketplaceConfigOutcome;
 pub use marketplace_edit::record_user_marketplace;
+pub use marketplace_edit::remove_user_marketplace;
+pub use marketplace_edit::remove_user_marketplace_config;
 pub use mcp_edit::ConfigEditsBuilder;
 pub use mcp_edit::load_global_mcp_servers;
 pub use mcp_types::AppToolApproval;

codex-rs/config/src/marketplace_edit.rs

@@ -19,6 +19,13 @@ pub struct MarketplaceConfigUpdate<'a> {
     pub sparse_paths: &'a [String],
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum RemoveMarketplaceConfigOutcome {
+    Removed,
+    NotFound,
+    NameCaseMismatch { configured_name: String },
+}
+
 pub fn record_user_marketplace(
     codex_home: &Path,
     marketplace_name: &str,
@@ -31,6 +38,36 @@ pub fn record_user_marketplace(
     fs::write(config_path, doc.to_string())
 }
 
+pub fn remove_user_marketplace(codex_home: &Path, marketplace_name: &str) -> std::io::Result<bool> {
+    let outcome = remove_user_marketplace_config(codex_home, marketplace_name)?;
+    Ok(outcome == RemoveMarketplaceConfigOutcome::Removed)
+}
+
+pub fn remove_user_marketplace_config(
+    codex_home: &Path,
+    marketplace_name: &str,
+) -> std::io::Result<RemoveMarketplaceConfigOutcome> {
+    let config_path = codex_home.join(CONFIG_TOML_FILE);
+    let mut doc = match fs::read_to_string(&config_path) {
+        Ok(raw) => raw
+            .parse::<DocumentMut>()
+            .map_err(|err| std::io::Error::new(ErrorKind::InvalidData, err))?,
+        Err(err) if err.kind() == ErrorKind::NotFound => {
+            return Ok(RemoveMarketplaceConfigOutcome::NotFound);
+        }
+        Err(err) => return Err(err),
+    };
+
+    let outcome = remove_marketplace(&mut doc, marketplace_name);
+    if outcome != RemoveMarketplaceConfigOutcome::Removed {
+        return Ok(outcome);
+    }
+
+    fs::create_dir_all(codex_home)?;
+    fs::write(config_path, doc.to_string())?;
+    Ok(RemoveMarketplaceConfigOutcome::Removed)
+}
+
 fn read_or_create_document(config_path: &Path) -> std::io::Result<DocumentMut> {
     match fs::read_to_string(config_path) {
         Ok(raw) => raw
@@ -80,8 +117,160 @@ fn upsert_marketplace(
     marketplaces.insert(marketplace_name, TomlItem::Table(entry));
 }
 
+fn remove_marketplace(
+    doc: &mut DocumentMut,
+    marketplace_name: &str,
+) -> RemoveMarketplaceConfigOutcome {
+    let root = doc.as_table_mut();
+    let Some(marketplaces_item) = root.get_mut("marketplaces") else {
+        return RemoveMarketplaceConfigOutcome::NotFound;
+    };
+
+    let mut remove_marketplaces = false;
+    let outcome = match marketplaces_item {
+        TomlItem::Table(marketplaces) => {
+            let outcome = if marketplaces.remove(marketplace_name).is_some() {
+                RemoveMarketplaceConfigOutcome::Removed
+            } else if let Some(configured_name) =
+                case_mismatched_key(marketplaces.iter().map(|(key, _)| key), marketplace_name)
+            {
+                RemoveMarketplaceConfigOutcome::NameCaseMismatch { configured_name }
+            } else {
+                RemoveMarketplaceConfigOutcome::NotFound
+            };
+            remove_marketplaces = marketplaces.is_empty();
+            outcome
+        }
+        TomlItem::Value(value) => {
+            let Some(marketplaces) = value.as_inline_table_mut() else {
+                return RemoveMarketplaceConfigOutcome::NotFound;
+            };
+            let outcome = if marketplaces.remove(marketplace_name).is_some() {
+                RemoveMarketplaceConfigOutcome::Removed
+            } else if let Some(configured_name) =
+                case_mismatched_key(marketplaces.iter().map(|(key, _)| key), marketplace_name)
+            {
+                RemoveMarketplaceConfigOutcome::NameCaseMismatch { configured_name }
+            } else {
+                RemoveMarketplaceConfigOutcome::NotFound
+            };
+            remove_marketplaces = marketplaces.is_empty();
+            outcome
+        }
+        _ => RemoveMarketplaceConfigOutcome::NotFound,
+    };
+
+    if outcome == RemoveMarketplaceConfigOutcome::Removed && remove_marketplaces {
+        root.remove("marketplaces");
+    }
+    outcome
+}
+
+fn case_mismatched_key<'a>(
+    mut keys: impl Iterator<Item = &'a str>,
+    requested_name: &str,
+) -> Option<String> {
+    keys.find(|key| *key != requested_name && key.eq_ignore_ascii_case(requested_name))
+        .map(str::to_string)
+}
+
 fn new_implicit_table() -> TomlTable {
     let mut table = TomlTable::new();
     table.set_implicit(true);
     table
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+    use tempfile::TempDir;
+
+    #[test]
+    fn remove_user_marketplace_removes_requested_entry() {
+        let codex_home = TempDir::new().unwrap();
+        let update = MarketplaceConfigUpdate {
+            last_updated: "2026-04-13T00:00:00Z",
+            last_revision: None,
+            source_type: "git",
+            source: "https://github.com/owner/repo.git",
+            ref_name: Some("main"),
+            sparse_paths: &[],
+        };
+        record_user_marketplace(codex_home.path(), "debug", &update).unwrap();
+        record_user_marketplace(codex_home.path(), "other", &update).unwrap();
+
+        let removed = remove_user_marketplace(codex_home.path(), "debug").unwrap();
+
+        assert!(removed);
+        let config: toml::Value =
+            toml::from_str(&fs::read_to_string(codex_home.path().join(CONFIG_TOML_FILE)).unwrap())
+                .unwrap();
+        let marketplaces = config
+            .get("marketplaces")
+            .and_then(toml::Value::as_table)
+            .unwrap();
+        assert_eq!(marketplaces.len(), 1);
+        assert!(marketplaces.contains_key("other"));
+    }
+
+    #[test]
+    fn remove_user_marketplace_returns_false_when_missing() {
+        let codex_home = TempDir::new().unwrap();
+
+        let removed = remove_user_marketplace(codex_home.path(), "debug").unwrap();
+
+        assert!(!removed);
+    }
+
+    #[test]
+    fn remove_user_marketplace_config_reports_case_mismatch() {
+        let codex_home = TempDir::new().unwrap();
+        let update = MarketplaceConfigUpdate {
+            last_updated: "2026-04-13T00:00:00Z",
+            last_revision: None,
+            source_type: "git",
+            source: "https://github.com/owner/repo.git",
+            ref_name: Some("main"),
+            sparse_paths: &[],
+        };
+        record_user_marketplace(codex_home.path(), "debug", &update).unwrap();
+
+        let outcome = remove_user_marketplace_config(codex_home.path(), "Debug").unwrap();
+
+        assert_eq!(
+            outcome,
+            RemoveMarketplaceConfigOutcome::NameCaseMismatch {
+                configured_name: "debug".to_string()
+            }
+        );
+    }
+
+    #[test]
+    fn remove_user_marketplace_config_removes_inline_table_entry() {
+        let codex_home = TempDir::new().unwrap();
+        fs::write(
+            codex_home.path().join(CONFIG_TOML_FILE),
+            r#"
+marketplaces = {
+  debug = { source_type = "git", source = "https://github.com/owner/repo.git" },
+  other = { source_type = "local", source = "/tmp/marketplace" },
+}
+"#,
+        )
+        .unwrap();
+
+        let outcome = remove_user_marketplace_config(codex_home.path(), "debug").unwrap();
+
+        assert_eq!(outcome, RemoveMarketplaceConfigOutcome::Removed);
+        let config: toml::Value =
+            toml::from_str(&fs::read_to_string(codex_home.path().join(CONFIG_TOML_FILE)).unwrap())
+                .unwrap();
+        let marketplaces = config
+            .get("marketplaces")
+            .and_then(toml::Value::as_table)
+            .unwrap();
+        assert_eq!(marketplaces.len(), 1);
+        assert!(marketplaces.contains_key("other"));
+    }
+}