Environment
- codex-cli version:
codex-cli 0.147.0-alpha.6.6（alpha channel）
- OS: Windows 11 (native, x64)
- MCP server type: streamable HTTP (ASP.NET / IIS), responses encoded as SSE (
Content-Type: text/event-stream), stateless (no Mcp-Session-Id header returned)
- Server side verified healthy: direct
curl initialize / notifications/initialized / tools/list returns 200/202/200 with the full tool list
config.toml (minimal repro)
[mcp_servers.example-erp]
enabled = true
url = "http://<mcp-host>/mcp"
[mcp_servers.example-erp.http_headers]
Authorization = "Bearer <token>"
Steps to reproduce
- Configure a streamable HTTP MCP server as above (server returns tools via
tools/list).
- Run:
codex exec --json --skip-git-repo-check --sandbox workspace-write -C <temp-dir> -m <model> -c notify=[] "Call the MCP tool <tool> and return the result."
- Observe the agent's available tool set.
Expected behavior
Tools returned by tools/list are registered and callable by the model — as in Codex desktop (ChatGPT app) with the same config, where the same tools are visible and usable.
Actual behavior
The model reports the tools do not exist (e.g. "no erp_describe / erp_query tool in this session"). The MCP connection itself works fine:
- codex sends
initialize → notifications/initialized → tools/list and receives 200 with all tools (verified by a local reverse proxy capturing the actual HTTP exchange).
list_mcp_resources with server=<id> reaches the server and returns -32601: Method 'resources/list' is not available — proving the connection and authentication are working (a wrong token would have produced 401).- The model's tool set only contains built-in tools (
shell_command, list_mcp_resources, ...); no tools from tools/list appear.
Config variants tried (none changed the behavior)
http_headers static Authorization (original)bearer_token_env_var instead of the static header- explicit
enabled_tools allowlist listing all server tools
-c features.tool_call_mcp_elicitation=falseapproval_policy = { granular = { sandbox_approval=true, rules=true, mcp_elicitations=true, request_permissions=true, skill_approval=true } }--sandbox read-only vs workspace-write; with/without -C and --skip-git-repo-check; temp dir vs trusted project dir- direct connection vs local reverse proxy
Diagnostics already performed
codex mcp list / codex mcp get <id> / codex doctor: server shown as enabled, transport streamable_http, auth "Bearer token", doctor reports MCP servers healthy (0 disabled, 0 failed).RUST_LOG=codex_core=trace,reqwest=trace: shows the HTTP connection to the MCP host and the completed handshake, but no tool registration from the tools/list response.- Feature flags in this build:
tool_call_mcp_elicitation = stable/true, mcp_2026_07_28 = under development/false, non_prefixed_mcp_tool_names = under development/false.
Impact
This blocks headless/non-interactive codex exec usage with streamable HTTP MCP servers (agent cannot use any MCP tool), while interactive clients (desktop) work with the identical configuration.
Version
codex --version → codex-cli 0.147.0-alpha.6.6
Environment
codex-cli 0.147.0-alpha.6.6（alpha channel）Content-Type: text/event-stream), stateless (noMcp-Session-Idheader returned)curlinitialize/notifications/initialized/tools/listreturns 200/202/200 with the full tool listconfig.toml (minimal repro)
Steps to reproduce
tools/list).Expected behavior
Tools returned by
tools/listare registered and callable by the model — as in Codex desktop (ChatGPT app) with the same config, where the same tools are visible and usable.Actual behavior
The model reports the tools do not exist (e.g. "no erp_describe / erp_query tool in this session"). The MCP connection itself works fine:
initialize→notifications/initialized→tools/listand receives 200 with all tools (verified by a local reverse proxy capturing the actual HTTP exchange).list_mcp_resourceswithserver=<id>reaches the server and returns-32601: Method 'resources/list' is not available— proving the connection and authentication are working (a wrong token would have produced 401).shell_command,list_mcp_resources, ...); no tools fromtools/listappear.Config variants tried (none changed the behavior)
http_headersstaticAuthorization(original)bearer_token_env_varinstead of the static headerenabled_toolsallowlist listing all server tools-c features.tool_call_mcp_elicitation=falseapproval_policy = { granular = { sandbox_approval=true, rules=true, mcp_elicitations=true, request_permissions=true, skill_approval=true } }--sandbox read-onlyvsworkspace-write; with/without-Cand--skip-git-repo-check; temp dir vs trusted project dirDiagnostics already performed
codex mcp list/codex mcp get <id>/codex doctor: server shown as enabled, transportstreamable_http, auth "Bearer token", doctor reports MCP servers healthy (0 disabled, 0 failed).RUST_LOG=codex_core=trace,reqwest=trace: shows the HTTP connection to the MCP host and the completed handshake, but no tool registration from thetools/listresponse.tool_call_mcp_elicitation= stable/true,mcp_2026_07_28= under development/false,non_prefixed_mcp_tool_names= under development/false.Impact
This blocks headless/non-interactive
codex execusage with streamable HTTP MCP servers (agent cannot use any MCP tool), while interactive clients (desktop) work with the identical configuration.Version
codex --version→codex-cli 0.147.0-alpha.6.6