Codex does not follow MCP `tools/list` pagination via `nextCursor`

What version of Codex CLI is running?

codex-cli 0.140.0

What subscription do you have?

ChatGPT Pro

Which model were you using?

gpt-5.5

What platform is your computer?

Darwin 25.5.0 arm64 arm

What terminal emulator and version are you using (if applicable)?

zsh (/bin/zsh)

Codex doctor report

overallStatus: fail
codexVersion: 0.140.0
config.load: ok
mcp.config: ok
auth.credentials: ok
network.provider_reachability: ok
network.websocket_reachability: ok
terminal.env: fail because TERM=dumb
updates.status: ok, latest version: 0.140.0

What issue are you seeing?

Codex CLI appears not to follow MCP tools/list pagination when building the callable MCP tool set.

When an MCP server returns a tools/list response with nextCursor, Codex exposes only the first page of tools. Tools returned on later pages are not available as callable MCP tools.

This makes paginated MCP tool discovery incomplete.

I first observed this with an MCP server where MCP Inspector can load additional tools via “more tools” and execute a tool from a later page, but Codex only exposes the first page.

What steps can reproduce the bug?

I reproduced this with a minimal local stdio MCP server.

The server behaves as follows:

• First tools/list response:
• returns 30 tools
• includes nextCursor: "page-2"
• Second tools/list response with cursor: "page-2":
• returns an additional tool named github-mcp-server___search_repositories

When connecting Codex CLI 0.140.0 to this server, Codex only exposed the first 30 tools. The tool from the second page was not callable.

Server-side received requests:

{"method":"initialize","id":0}
{"method":"tools/list","id":1,"params":{"_meta":{"progressToken":0}}}

There was no second tools/list request with cursor: "page-2".
Codex output:

probe exposes 30 callable tools.

FAIL:
github-mcp-server___search_repositories is not available
only mcp__probe.page1_tool_* tools were callable

Source investigation:
In Codex rust-v0.140.0, the callable tool discovery path appears to call tools/list once with params = None:
https://github.com/openai/codex/blob/rust-v0.140.0/codex-rs/codex-mcp/src/rmcp_client.rs#L345-L353

The lower-level client already carries next_cursor:
https://github.com/openai/codex/blob/rust-v0.140.0/codex-rs/rmcp-client/src/rmcp_client.rs#L487-L520

Codex also already follows cursor pagination for resources/list / resource_templates/list:
https://github.com/openai/codex/blob/rust-v0.140.0/codex-rs/codex-mcp/src/connection_manager.rs#L541-L568

What is the expected behavior?

If tools/list returns nextCursor, Codex should continue requesting subsequent pages by sending another tools/list request with that cursor.

Example:

{
  "method": "tools/list",
  "params": {
    "cursor": "page-2"
  }
}

Codex should expose tools from all pages as callable MCP tools.
This would make Codex’s MCP tool discovery consistent with MCP pagination and with Codex’s existing resource pagination behavior.

Additional information

MCP spec references:

• tools/list supports pagination:

https://modelcontextprotocol.io/specification/2025-06-18/server/tools

• MCP pagination:

https://modelcontextprotocol.io/specification/2025-06-18/server/utilities/pagination

I searched for existing Codex issues/PRs using:

• tools/list nextCursor
• MCP pagination tools/list
• list_tools_with_connector_ids

I did not find an existing matching issue.