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Codex refuses ?codemode=false: tools/list has more than its 2,048-tool cap

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
54/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
typescript
Domain
api

Research direction

Start by reading the /mcp endpoint and the tools/list handling, then check how the catalogue is assembled and how products.json defines products. Reproduce with the staging URL and compare the direct-tool catalogue size with the 2,048-tool limit. Done when Codex can use an appropriate direct-tool subset or the issue establishes a workable alternative; pagination still needs investigation.

Written by the indexing model from the issue text.

Description

Codex can't load the direct-tool surface (/mcp?codemode=false). It refuses any MCP server whose tools/list returns more than 2,048 tools, and drops the server at startup:

codex_mcp::rmcp_client: MCP server startup failed server_name="cf-stg-direct"
  error=tools/list exceeded the catalog limit of 2048 items

The model then reports that none of the server's tools are available.

Repro

Codex CLI 0.157.0, logged in to https://staging.mcp.cloudflare.com/mcp?codemode=false:

codex mcp add cf-stg-direct --url "https://staging.mcp.cloudflare.com/mcp?codemode=false"
codex mcp login cf-stg-direct
RUST_LOG=codex_mcp=debug codex exec "Call the cf-stg-direct MCP tool accounts_list once."

The result is the same with and without Codex's code_mode and mcp_2026_07_28 features.

Scope

  • With the Forge catalogue (#247), ?codemode=false lists 2,905 tools (docs, whoami and 2,903 endpoints).
  • Production's current catalogue is larger: about 3,661 tools.
  • The default Code Mode server (/mcp, four tools) is unaffected.
  • OpenCode v2 loads the full catalogue and drives it through its own Code Mode, so the problem is the cap, not the catalogue's shape.
Dominant language
TypeScript
Stars
946
Forks
131
Avg merge
1d 18h
Merged PRs (30d)
29

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