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GPT-5.6 Sol hides discovered MCP tools without exposing tool_search #33609
Description
What version of Codex CLI is running?
0.144.5
What subscription do you have?
Pro
Which model were you using?
gpt-5.6-sol
What platform is your computer?
Darwin 25.5.0 arm64 arm
What terminal emulator and version are you using (if applicable)?
No response
Codex doctor report
{
"schemaVersion": 1,
"generatedAt": "1784211109s since unix epoch",
"overallStatus": "warning",
"codexVersion": "0.144.5",
"checks": {
"app_server.status": {
"id": "app_server.status",
"category": "app-server",
"status": "ok",
"summary": "background server is not running",
"details": {
"control socket": "/Users/admin/.codex/app-server-control/app-server-control.sock",
"daemon state dir": "/Users/admin/.codex/app-server-daemon",
"mode": "ephemeral",
"pid file": "/Users/admin/.codex/app-server-daemon/app-server.pid (missing)",
"settings": "/Users/admin/.codex/app-server-daemon/settings.json (missing)",
"status": "not running",
"update-loop pid file": "/Users/admin/.codex/app-server-daemon/app-server-updater.pid (missing)"
},
"remediation": null,
"durationMs": 0
},
"auth.credentials": {
"id": "auth.credentials",
"category": "auth",
"status": "ok",
"summary": "auth is configured",
"details": {
"auth file": "/Users/admin/.codex/auth.json",
"auth storage mode": "File",
"stored API key": "false",
"stored ChatGPT tokens": "true",
"stored agent identity": "false",
"stored auth mode": "chatgpt"
},
"remediation": null,
"durationMs": 0
},
"config.load": {
"id": "config.load",
"category": "config",
"status": "ok",
"summary": "config loaded",
"details": {
"CODEX_HOME": "/Users/admin/.codex",
"config.toml": "/Users/admin/.codex/config.toml",
"config.toml parse": "ok",
"cwd": "/Users/admin/RustProjects/mcp-test",
"enabled feature flags": "shell_tool, unified_exec, shell_snapshot, code_mode_host, terminal_resize_reflow, sqlite, hooks, enable_request_compression, multi_agent, apps, tool_search_always_defer_mcp_tools, tool_suggest, plugins, in_app_browser, browser_use, browser_use_full_cdp_access, browser_use_external, computer_use, remote_plugin, plugin_sharing, image_generation, resize_all_images, skill_mcp_dependency_install, mentions_v2, steer, guardian_approval, goals, collaboration_modes, tool_call_mcp_elicitation, auth_elicitation, personality, fast_mode, tui_app_server, prevent_idle_sleep, remote_compaction_v2, workspace_dependencies",
"feature flag overrides": "prevent_idle_sleep=true",
"feature flags enabled": "36",
"log dir": "/Users/admin/.codex/log",
"mcp servers": "2",
"model": "gpt-5.6-sol",
"model provider": "openai",
"sqlite home": "/Users/admin/.codex"
},
"remediation": null,
"durationMs": 0
},
"git.environment": {
"id": "git.environment",
"category": "git",
"status": "ok",
"summary": "git version 2.50.1 (Apple Git-155)",
"details": {
".git entry": "directory",
"PATH git #1": "/usr/bin/git",
"PATH git entries": "1",
"git branch": "main",
"git build options": "git version 2.50.1 (Apple Git-155); cpu: arm64; no commit associated with this build; sizeof-long: 8; sizeof-size_t: 8; shell-path: /bin/sh; feature: fsmonitor--daemon; libcurl: 8.7.1; zlib: 1.2.12; SHA-1: SHA1_DC; SHA-256: SHA256_BLK",
"git exec path": "/Library/Developer/CommandLineTools/usr/libexec/git-core",
"git version": "git version 2.50.1 (Apple Git-155)",
"repo detected": "true",
"repo root": "/Users/admin/RustProjects/mcp-test",
"selected git": "/usr/bin/git"
},
"remediation": null,
"durationMs": 98
},
"installation": {
"id": "installation",
"category": "install",
"status": "ok",
"summary": "installation looks consistent",
"details": {
"PATH codex #1": "/opt/homebrew/bin/codex",
"current executable": "/opt/homebrew/bin/codex",
"install context": "brew",
"managed by bun": "false",
"managed by npm": "false",
"managed by pnpm": "false",
"managed package root": "not set"
},
"remediation": null,
"durationMs": 3
},
"mcp.config": {
"id": "mcp.config",
"category": "mcp",
"status": "warning",
"summary": "MCP configuration has optional issues",
"details": {
"configured servers": "2",
"disabled servers": "0",
"optional reachability failed": "kraka: http://127.0.0.1:8000/mcp (HEAD connect failed; GET connect failed)",
"streamable_http servers": "2"
},
"remediation": "Set the missing MCP env vars or disable the affected server.",
"durationMs": 332
},
"network.env": {
"id": "network.env",
"category": "network",
"status": "ok",
"summary": "network-related environment looks readable",
"details": {
"proxy env vars": "none"
},
"remediation": null,
"durationMs": 0
},
"network.provider_reachability": {
"id": "network.provider_reachability",
"category": "reachability",
"status": "ok",
"summary": "active provider endpoints are reachable over HTTP",
"details": {
"ChatGPT base URL": "https://chatgpt.com/backend-api/ reachable (HTTP 403)",
"reachability mode": "ChatGPT auth"
},
"remediation": null,
"durationMs": 152
},
"network.websocket_reachability": {
"id": "network.websocket_reachability",
"category": "websocket",
"status": "ok",
"summary": "Responses WebSocket handshake succeeded",
"details": {
"DNS": "2 IPv4, 0 IPv6, first IPv4",
"auth mode": "chatgpt",
"connect timeout": "15000 ms",
"endpoint": "wss://chatgpt.com/backend-api/<redacted>",
"handshake result": "HTTP 101 Switching Protocols",
"model provider": "openai",
"models etag present": "true",
"provider name": "OpenAI",
"proxy env vars": "none",
"reasoning header": "false",
"server model present": "false",
"supports websockets": "true",
"wire API": "responses"
},
"remediation": null,
"durationMs": 1019
},
"runtime.provenance": {
"id": "runtime.provenance",
"category": "runtime",
"status": "ok",
"summary": "running brew on macos-aarch64",
"details": {
"commit": "unknown",
"current executable": "/opt/homebrew/bin/codex",
"install method": "brew",
"platform": "macos-aarch64",
"version": "0.144.5"
},
"remediation": null,
"durationMs": 0
},
"runtime.search": {
"id": "runtime.search",
"category": "search",
"status": "ok",
"summary": "search is OK (system)",
"details": {
"search command": "rg",
"search command readiness": "ripgrep 15.1.0",
"search provider": "system"
},
"remediation": null,
"durationMs": 2
},
"sandbox.helpers": {
"id": "sandbox.helpers",
"category": "sandbox",
"status": "ok",
"summary": "sandbox configuration is readable",
"details": {
"approval policy": "OnRequest",
"codex-linux-sandbox helper": "none",
"execve wrapper helper": "/Users/admin/.codex/tmp/arg0/codex-arg0pFSY38/codex-execve-wrapper",
"filesystem sandbox": "restricted",
"network sandbox": "restricted"
},
"remediation": null,
"durationMs": 0
},
"state.paths": {
"id": "state.paths",
"category": "state",
"status": "ok",
"summary": "state paths and databases are inspectable",
"details": {
"CODEX_HOME": "/Users/admin/.codex (dir)",
"active rollout files": "735 files, 796735971 total bytes, 1083994 average bytes",
"archived rollout files": "0 files, 0 total bytes, 0 average bytes",
"goals DB": "/Users/admin/.codex/goals_1.sqlite (file)",
"goals DB integrity": "ok",
"log DB": "/Users/admin/.codex/logs_2.sqlite (file)",
"log DB integrity": "ok",
"log dir": "/Users/admin/.codex/log (dir)",
"memories DB": "/Users/admin/.codex/memories_1.sqlite (file)",
"memories DB integrity": "ok",
"sqlite home": "/Users/admin/.codex (dir)",
"state DB": "/Users/admin/.codex/state_5.sqlite (file)",
"state DB integrity": "ok"
},
"remediation": null,
"durationMs": 195
},
"state.rollout_db_parity": {
"id": "state.rollout_db_parity",
"category": "threads",
"status": "ok",
"summary": "rollout files and state DB thread inventory agree",
"details": {
"default model provider": "openai",
"rollout DB active files": "735",
"rollout DB active rows": "735",
"rollout DB archive mismatches": "0",
"rollout DB archived files": "0",
"rollout DB archived rows": "0",
"rollout DB duplicate DB paths": "0",
"rollout DB duplicate rollout thread ids": "0",
"rollout DB malformed file names": "0",
"rollout DB missing active rows": "0",
"rollout DB missing archived rows": "0",
"rollout DB model providers": "openai=735",
"rollout DB rows": "735",
"rollout DB scan cap reached": "false",
"rollout DB scan errors": "0",
"rollout DB sources": "subagent:thread_spawn=281, cli=234, exec=160, subagent:review=54, vscode=6",
"rollout DB stale rows": "0"
},
"remediation": null,
"durationMs": 2602
},
"system.environment": {
"id": "system.environment",
"category": "system",
"status": "ok",
"summary": "OS language en-US",
"details": {
"EDITOR": "not set",
"LANG": "C.UTF-8",
"LC_CTYPE": "UTF-8",
"VISUAL": "not set",
"os": "Mac OS 26.5.2 [64-bit]",
"os language": "en-US",
"os type": "Mac OS",
"os version": "26.5.2"
},
"remediation": null,
"durationMs": 3
},
"terminal.env": {
"id": "terminal.env",
"category": "terminal",
"status": "ok",
"summary": "terminal metadata was detected",
"details": {
"COLORTERM": "truecolor",
"DISPLAY": "present",
"TERM_PROGRAM": "WarpTerminal",
"color output": "enabled",
"effective locale": "UTF-8",
"stderr is terminal": "true",
"stdin is terminal": "true",
"stdout is terminal": "true",
"terminal": "Warp",
"terminal size": "93x24",
"terminal version": "v0.2026.07.01.09.21.stable_01"
},
"remediation": null,
"durationMs": 0
},
"terminal.title": {
"id": "terminal.title",
"category": "title",
"status": "ok",
"summary": "terminal title default",
"details": {
"terminal title activity": "true",
"terminal title items": "activity, project-name",
"terminal title project source": "git repo root",
"terminal title project value": "mcp-test",
"terminal title source": "default"
},
"remediation": null,
"durationMs": 0
},
"updates.status": {
"id": "updates.status",
"category": "updates",
"status": "ok",
"summary": "update configuration is locally consistent",
"details": {
"cached latest version": "0.144.5",
"check for update on startup": "true",
"last checked at": "2026-07-16T13:09:51.525097Z",
"latest version": "0.144.5",
"latest version status": "current version is not older",
"update action": "brew upgrade --cask codex",
"version cache": "/Users/admin/.codex/version.json"
},
"remediation": null,
"durationMs": 41
}
}
}What issue are you seeing?
Summary
Codex CLI 0.144.5 successfully discovers all eight tools from a local
synthetic MCP server, but a fresh gpt-5.6-sol session exposes neither the
MCP tools nor tool_search.
The same server, configuration, and prompt work with gpt-5.4.
Environment
- Codex CLI:
0.144.5 - macOS 26.5.2, Apple Silicon
- Native OpenAI provider with ChatGPT authentication
- MCP: unauthenticated Streamable HTTP
- Failing model:
gpt-5.6-sol - Working model:
gpt-5.4 - Reproduction server: https://github.com/ariloudev/mcp-test
What steps can reproduce the bug?
Reproduction
Start the synthetic server:
git clone https://github.com/ariloudev/mcp-test
cd mcp-test
uv sync
.venv/bin/python server.pyRegister it:
codex mcp add kraka --url http://127.0.0.1:8000/mcpThe server exposes eight deterministic tools, including echo. Direct
tools/list returns all eight successfully.
Run:
codex -m gpt-5.6-sol \
--dangerously-bypass-approvals-and-sandbox \
exec --skip-git-repo-check \
'Use the registered kraka MCP echo tool directly with message "hello from
Codex". Do not use shell commands, curl, Python, filesystem inspection,
MCP resources, or protocol-level HTTP. Report the returned value.'Actual result:
I can’t call the registered `kraka` echo tool because it isn’t exposed in
this session’s available tools.
Codex logs nevertheless confirm discovery:
listed MCP server tools while building tool list server_name=kraka
tool_count=8
No tool_search_call or MCP function call occurs.
Repeat with gpt-5.4:
codex -m gpt-5.4 \
--dangerously-bypass-approvals-and-sandbox \
exec --skip-git-repo-check \
'Use the registered kraka MCP echo tool directly with message "hello from
Codex". Do not use shell commands, curl, Python, filesystem inspection,
MCP resources, or protocol-level HTTP. Report the returned value.'This succeeds:
mcp: kraka/echo started
mcp: kraka/echo (completed)
Returned value: `hello from Codex`
The GPT-5.4 rollout contains:
tool_search_call
→ tool_search_output containing mcp__kraka
→ mcp__kraka/echo
→ "hello from Codex"
Diagnostics
tool_search removed false
tool_search_always_defer_mcp_tools removed true
Model metadata:
gpt-5.6-sol: supports_search_tool=true, use_responses_lite=true
gpt-5.4: supports_search_tool=true, use_responses_lite=false
What is the expected behavior?
Expected behavior
If Codex defers MCP tools, it must expose tool_search. If tool_search is
unavailable, the MCP tools must remain directly callable.
Additional information
Suspected cause
This appears specific to the GPT-5.6 Sol Responses Lite path: Codex defers
the discovered MCP tools but omits the client-side tool_search required to
load them.
Potentially related changes:
- [[codex] Use tool search for MCP tools by default #29486 — Use tool search for MCP tools by default](https://github.com/
[codex] Use tool search for MCP tools by default #29486) - [[codex] Use input items for Responses Lite tools #27946 — Use input items for Responses Lite tools](https://github.com/
[codex] Use input items for Responses Lite tools #27946)
Related report: #19425
Activity
github-actions commentedon Jul 16, 2026
Potential duplicates detected. Please review them and close your issue if it is a duplicate.
Powered by Codex Action
DainisGorbunovs commentedon Jul 16, 2026
Workarounds
Override originator
Run codex with
CODEX_INTERNAL_ORIGINATOR_OVERRIDEenv variable set tocodex_cli_rs_github_issue_33609:Live catalog currently returns
code_mode_onlyforcodex_cli_rs_github_issue_33609originator, whilecodex_cli_rsoriginator getsdirecttool mode.Add to direct only tool namespace
Temporary per-namespace workaround: add this to
~/.codex/config.toml(replacemcp__krakawith your MCP namespace):Restart Codex and start a new session afterward.
Explanation
A likely explanation based on the current model metadata and Codex source:
Draft fix
I've drafted a fix for this and validated it works for me: main...DainisGorbunovs:codex:agent/fix-responses-lite-tool-search
takove commentedon Jul 16, 2026
Independent verification on the same affected stack:
26.707.919480.144.526.715.12143gpt-5.6-solThe current remote model cache still advertises:
{ "tool_mode": "direct", "supports_search_tool": true, "use_responses_lite": true }node_repland the Chrome bridge were healthy underneath, but neithermcp__node_repl__jsnortool_searchreached the task. Forcing direct MCP exposure restorednode_repl, after which Chrome connected and listed the signed-in browser tabs successfully. This confirms a tool-exposure regression rather than an extension/native-host failure.The repository's contribution policy says unsolicited PRs will be closed. Since @DainisGorbunovs has already drafted and tested a focused patch, could a maintainer confirm whether that approach is acceptable and, if so, invite them to submit it? Patch: main...DainisGorbunovs:codex:agent/fix-responses-lite-tool-search
ariloudev commentedon Jul 17, 2026
Per #33575 this is now fixed on the backend. I can confirm, too.