[codex] Add marketplace/remove app-server RPC (#17751)

## Summary

Add a new app-server `marketplace/remove` RPC on top of the shared
marketplace-remove implementation.

This change:
- adds `MarketplaceRemoveParams` / `MarketplaceRemoveResponse` to the
app-server protocol
- wires the new request through `codex_message_processor`
- reuses the shared core marketplace-remove flow from the stacked
refactor PR
- updates generated schema files and adds focused app-server coverage

## Validation

- `just write-app-server-schema`
- `just fmt`
- heavy compile/test coverage deferred to GitHub CI per request

codex-rs/app-server/tests/suite/v2/marketplace_remove.rs

@@ -0,0 +1,105 @@
+use std::time::Duration;
+
+use anyhow::Result;
+use app_test_support::McpProcess;
+use app_test_support::to_response;
+use codex_app_server_protocol::JSONRPCResponse;
+use codex_app_server_protocol::MarketplaceRemoveParams;
+use codex_app_server_protocol::MarketplaceRemoveResponse;
+use codex_app_server_protocol::RequestId;
+use codex_config::MarketplaceConfigUpdate;
+use codex_config::record_user_marketplace;
+use codex_core::plugins::marketplace_install_root;
+use codex_utils_absolute_path::AbsolutePathBuf;
+use pretty_assertions::assert_eq;
+use tempfile::TempDir;
+use tokio::time::timeout;
+
+const DEFAULT_TIMEOUT: Duration = Duration::from_secs(10);
+
+fn configured_marketplace_update() -> MarketplaceConfigUpdate<'static> {
+    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: &[],
+    }
+}
+
+fn write_installed_marketplace(codex_home: &std::path::Path, marketplace_name: &str) -> Result<()> {
+    let root = marketplace_install_root(codex_home).join(marketplace_name);
+    std::fs::create_dir_all(root.join(".agents/plugins"))?;
+    std::fs::write(root.join(".agents/plugins/marketplace.json"), "{}")?;
+    Ok(())
+}
+
+#[tokio::test]
+async fn marketplace_remove_deletes_config_and_installed_root() -> Result<()> {
+    let codex_home = TempDir::new()?;
+    record_user_marketplace(codex_home.path(), "debug", &configured_marketplace_update())?;
+    write_installed_marketplace(codex_home.path(), "debug")?;
+    let installed_root = marketplace_install_root(codex_home.path())
+        .join("debug")
+        .canonicalize()?;
+
+    let mut mcp = McpProcess::new(codex_home.path()).await?;
+    timeout(DEFAULT_TIMEOUT, mcp.initialize()).await??;
+
+    let request_id = mcp
+        .send_marketplace_remove_request(MarketplaceRemoveParams {
+            marketplace_name: "debug".to_string(),
+        })
+        .await?;
+
+    let response: JSONRPCResponse = timeout(
+        DEFAULT_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(request_id)),
+    )
+    .await??;
+    let response: MarketplaceRemoveResponse = to_response(response)?;
+    assert_eq!(
+        response,
+        MarketplaceRemoveResponse {
+            marketplace_name: "debug".to_string(),
+            installed_root: Some(AbsolutePathBuf::try_from(installed_root)?),
+        }
+    );
+
+    let config = std::fs::read_to_string(codex_home.path().join("config.toml"))?;
+    assert!(!config.contains("[marketplaces.debug]"));
+    assert!(
+        !marketplace_install_root(codex_home.path())
+            .join("debug")
+            .exists()
+    );
+    Ok(())
+}
+
+#[tokio::test]
+async fn marketplace_remove_rejects_unknown_marketplace() -> Result<()> {
+    let codex_home = TempDir::new()?;
+
+    let mut mcp = McpProcess::new(codex_home.path()).await?;
+    timeout(DEFAULT_TIMEOUT, mcp.initialize()).await??;
+
+    let request_id = mcp
+        .send_marketplace_remove_request(MarketplaceRemoveParams {
+            marketplace_name: "debug".to_string(),
+        })
+        .await?;
+
+    let err = timeout(
+        DEFAULT_TIMEOUT,
+        mcp.read_stream_until_error_message(RequestId::Integer(request_id)),
+    )
+    .await??;
+
+    assert_eq!(err.error.code, -32600);
+    assert_eq!(
+        err.error.message,
+        "marketplace `debug` is not configured or installed",
+    );
+    Ok(())
+}

codex-rs/app-server/tests/suite/v2/mod.rs

@@ -17,6 +17,7 @@ mod external_agent_config;
 mod fs;
 mod initialize;
 mod marketplace_add;
+mod marketplace_remove;
 mod mcp_resource;
 mod mcp_server_elicitation;
 mod mcp_server_status;