Excel MCP not working in ChatGPT (Codex)? Fixes
Failed It failed in our test on Oct 21, 2026. Below is the exact setup we used in ChatGPT (Codex) (codex-cli 0.162.0-alpha.17.2), every error we saw, and what to check, all from our own run log.
Date tested: · From our harness, not the maker’s claims · How we test
1. Use the install config we tested in ChatGPT (Codex)
[mcp_servers.excel]
command = "uvx"
args = ["excel-mcp-server", "stdio"]
env = {EXCEL_FILES_PATH="{SANDBOX}"}Replace any <YOUR_…> placeholder and local test paths with your own. Every client’s tested snippet is on the Excel MCP page.
2. Check that ChatGPT (Codex) connects to it
In our run the connect check was OK (connect time not recorded). Our check output:
server answered tool calls during the taskErrors we observed
- agent task: write read back: file not created: /workspace/timmy/harness/sandbox/office/out-codex.xlsx
- agent task: write read back (tool error during the run):
file not created: /workspace/timmy/harness/sandbox/office/out-codex.xlsx
Quoted from our run log. Secrets redacted. We list only what we saw.
More help
Excel MCP: all results and setup · Full ChatGPT (Codex) run · General ChatGPT (Codex) MCP troubleshooting
