Remove client_common tool re-exports (#16482)

## Why

`codex-rs/core/src/client_common.rs` still had a `tools` re-export
module that forwarded `codex_tools` types back into `codex-core`. After
the earlier extraction work in #16379, #16471, #16477, and #16481, that
extra layer no longer adds value.

Removing it keeps dependencies explicit: the `codex-core` modules that
actually use `ToolSpec` and related types now depend on `codex_tools`
directly instead of reaching through `client_common`.

## What Changed

- removed the `client_common::tools` re-export module from
`core/src/client_common.rs`
- updated the remaining `codex-core` consumers to import `codex_tools`
directly
- adjusted the affected test code to reference
`codex_tools::ResponsesApiTool` directly as well

This is a mechanical cleanup only. It does not change tool behavior or
runtime logic.

## Testing

- `cargo test -p codex-core client_common::tests`
- `cargo test -p codex-core tools::router::tests`
- `cargo test -p codex-core tools::context::tests`
- `cargo test -p codex-core tools::spec::tests`

codex-rs/core/src/client_common.rs

@@ -156,13 +156,6 @@ fn strip_total_output_header(output: &str) -> Option<(&str, u32)> {
     Some((remainder, total_lines))
 }
 
-pub(crate) mod tools {
-    #[cfg(test)]
-    pub(crate) use codex_tools::ResponsesApiTool;
-    pub(crate) use codex_tools::ToolSearchOutputTool;
-    pub(crate) use codex_tools::ToolSpec;
-}
-
 pub struct ResponseStream {
     pub(crate) rx_event: mpsc::Receiver<Result<ResponseEvent>>,
 }

codex-rs/core/src/tools/code_mode/mod.rs

@@ -14,7 +14,6 @@ use codex_protocol::models::ResponseInputItem;
 use serde_json::Value as JsonValue;
 use tokio_util::sync::CancellationToken;
 
-use crate::client_common::tools::ToolSpec;
 use crate::codex::Session;
 use crate::codex::TurnContext;
 use crate::function_tool::FunctionCallError;
@@ -28,6 +27,7 @@ use crate::tools::router::ToolCallSource;
 use crate::tools::router::ToolRouterParams;
 use crate::unified_exec::resolve_max_tokens;
 use codex_features::Feature;
+use codex_tools::ToolSpec;
 use codex_tools::tool_spec_to_code_mode_tool_definition;
 use codex_utils_output_truncation::TruncationPolicy;
 use codex_utils_output_truncation::formatted_truncate_text_content_items_with_policy;

codex-rs/core/src/tools/context.rs

@@ -1,4 +1,3 @@
-use crate::client_common::tools::ToolSearchOutputTool;
 use crate::codex::Session;
 use crate::codex::TurnContext;
 use crate::tools::TELEMETRY_PREVIEW_MAX_BYTES;
@@ -14,6 +13,7 @@ use codex_protocol::models::ResponseInputItem;
 use codex_protocol::models::SearchToolCallParams;
 use codex_protocol::models::ShellToolCallParams;
 use codex_protocol::models::function_call_output_content_items_to_text;
+use codex_tools::ToolSearchOutputTool;
 use codex_utils_output_truncation::TruncationPolicy;
 use codex_utils_output_truncation::formatted_truncate_text;
 use codex_utils_string::take_bytes_at_char_boundary;

codex-rs/core/src/tools/context_tests.rs

@@ -142,7 +142,7 @@ fn tool_search_payloads_roundtrip_as_tool_search_outputs() {
     };
     let response = ToolSearchOutput {
         tools: vec![ToolSearchOutputTool::Function(
-            crate::client_common::tools::ResponsesApiTool {
+            codex_tools::ResponsesApiTool {
                 name: "create_event".to_string(),
                 description: String::new(),
                 strict: false,

codex-rs/core/src/tools/js_repl/mod.rs

@@ -31,7 +31,6 @@ use tracing::trace;
 use tracing::warn;
 use uuid::Uuid;
 
-use crate::client_common::tools::ToolSpec;
 use crate::codex::Session;
 use crate::codex::TurnContext;
 use crate::exec::ExecCapturePolicy;
@@ -46,6 +45,7 @@ use codex_sandboxing::SandboxCommand;
 use codex_sandboxing::SandboxManager;
 use codex_sandboxing::SandboxTransformRequest;
 use codex_sandboxing::SandboxablePreference;
+use codex_tools::ToolSpec;
 use codex_utils_output_truncation::TruncationPolicy;
 use codex_utils_output_truncation::truncate_text;
 

codex-rs/core/src/tools/parallel.rs

@@ -9,7 +9,6 @@ use tracing::Instrument;
 use tracing::instrument;
 use tracing::trace_span;
 
-use crate::client_common::tools::ToolSpec;
 use crate::codex::Session;
 use crate::codex::TurnContext;
 use crate::error::CodexErr;
@@ -22,6 +21,7 @@ use crate::tools::router::ToolCall;
 use crate::tools::router::ToolCallSource;
 use crate::tools::router::ToolRouter;
 use codex_protocol::models::ResponseInputItem;
+use codex_tools::ToolSpec;
 
 #[derive(Clone)]
 pub(crate) struct ToolCallRuntime {

codex-rs/core/src/tools/registry.rs

@@ -3,7 +3,6 @@ use std::sync::Arc;
 use std::time::Duration;
 use std::time::Instant;
 
-use crate::client_common::tools::ToolSpec;
 use crate::function_tool::FunctionCallError;
 use crate::hook_runtime::record_additional_contexts;
 use crate::hook_runtime::run_post_tool_use_hooks;
@@ -25,6 +24,7 @@ use codex_hooks::HookToolInputLocalShell;
 use codex_hooks::HookToolKind;
 use codex_protocol::models::ResponseInputItem;
 use codex_tools::ConfiguredToolSpec;
+use codex_tools::ToolSpec;
 use codex_utils_readiness::Readiness;
 use serde_json::Value;
 use tracing::warn;

codex-rs/core/src/tools/router.rs

@@ -1,4 +1,3 @@
-use crate::client_common::tools::ToolSpec;
 use crate::codex::Session;
 use crate::codex::TurnContext;
 use crate::function_tool::FunctionCallError;
@@ -18,6 +17,7 @@ use codex_protocol::models::SearchToolCallParams;
 use codex_protocol::models::ShellToolCallParams;
 use codex_tools::ConfiguredToolSpec;
 use codex_tools::DiscoverableTool;
+use codex_tools::ToolSpec;
 use rmcp::model::Tool;
 use std::collections::HashMap;
 use std::sync::Arc;

codex-rs/core/src/tools/spec.rs

@@ -1,4 +1,3 @@
-use crate::client_common::tools::ToolSpec;
 use crate::mcp::CODEX_APPS_MCP_SERVER_NAME;
 use crate::mcp_connection_manager::ToolInfo;
 use crate::shell::Shell;
@@ -24,6 +23,7 @@ use codex_tools::DiscoverableTool;
 use codex_tools::ShellToolOptions;
 use codex_tools::SpawnAgentToolOptions;
 use codex_tools::ToolSearchAppSource;
+use codex_tools::ToolSpec;
 use codex_tools::ToolUserShellType;
 use codex_tools::ViewImageToolOptions;
 use codex_tools::WaitAgentTimeoutOptions;