OpenAI Codex · tool · fg-0504

Codex starts the first turn without tools from a slow MCP server

Tools from an MCP server are missing on the first prompt but appear later

Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100

Cause

When building the initial tool catalog, Codex waits only mcp_optional_startup_grace_ms, 1000 ms by default, for optional servers, and each server gets startup_timeout_sec, 10 seconds by default.

Fix

Raise startup_timeout_sec for slow servers, mark servers the task depends on as required, or set the grace to 0 to wait for each server's own timeout.

Apply

# ~/.codex/config.toml
mcp_optional_startup_grace_ms = 0
[mcp_servers.docs]
command = "npx"
args = ["-y", "docs-mcp"]
startup_timeout_sec = 30
required = true

Affects: Codex CLI, IDE extension, and ChatGPT desktop app, as of 2026-10

Sources

https://learn.chatgpt.com/docs/extend/mcp

Have your agent know this before it fails

claude mcp add --transport http footgun https://getfootgun.com/api/mcp