exec_command intermittently unsupported: "unsupported call: exec_command" then tool disappears entirely after disabling shell_tool

What version of Codex CLI is running?

codex-cli 0.143.0

What subscription do you have?

ChatGPT Plus

Which model were you using?

gpt-5.5 (also reproduced on gpt-5.4)

What platform is your computer?

Linux 7.0.0-27-generic x86_64 unknown Ubuntu 26.04 LTS

What terminal emulator and version are you using (if applicable)?

Standard Linux terminal (pts), no multiplexer (tmux/screen/zellij) in use

Codex doctor report

{
  "schemaVersion": 1,
  "generatedAt": "1783568819s since unix epoch",
  "overallStatus": "ok",
  "codexVersion": "0.143.0",
  "checks": {
    "app_server.status": {
      "id": "app_server.status",
      "category": "app-server",
      "status": "ok",
      "summary": "background server is not running",
      "details": {
        "control socket": "/home/seb/.codex/app-server-control/app-server-control.sock",
        "daemon state dir": "/home/seb/.codex/app-server-daemon",
        "mode": "ephemeral",
        "pid file": "/home/seb/.codex/app-server-daemon/app-server.pid (missing)",
        "settings": "/home/seb/.codex/app-server-daemon/settings.json (missing)",
        "status": "not running",
        "update-loop pid file": "/home/seb/.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": "/home/seb/.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": "/home/seb/.codex",
        "config.toml": "/home/seb/.codex/config.toml",
        "config.toml parse": "ok",
        "cwd": "/home/seb",
        "enabled feature flags": "unified_exec, shell_snapshot, terminal_resize_reflow, sqlite, memories, 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, personality, fast_mode, tui_app_server, remote_compaction_v2, workspace_dependencies",
        "feature flag overrides": "shell_tool=false, memories=true",
        "feature flags enabled": "33",
        "log dir": "/home/seb/.codex/log",
        "mcp servers": "0",
        "model": "gpt-5.5",
        "model provider": "openai",
        "sqlite home": "/home/seb/.codex"
      },
      "remediation": null,
      "durationMs": 0
    },
    "git.environment": {
      "id": "git.environment",
      "category": "git",
      "status": "ok",
      "summary": "git version 2.53.0",
      "details": {
        ".git entry": "directory",
        "PATH git #1": "/usr/bin/git",
        "PATH git #2": "/bin/git",
        "PATH git entries": "2",
        "git build options": "git version 2.53.0; cpu: x86_64; no commit associated with this build; sizeof-long: 8; sizeof-size_t: 8; shell-path: /bin/sh; rust: disabled; gettext: enabled; libcurl: 8.18.0; zlib: 1.3.1; SHA-1: SHA1_DC; SHA-256: SHA256_BLK; default-ref-format: files; default-hash: sha1",
        "git exec path": "/usr/lib/git-core",
        "git version": "git version 2.53.0",
        "repo detected": "true",
        "repo root": "/home/seb",
        "selected git": "/usr/bin/git"
      },
      "remediation": null,
      "durationMs": 94
    },
    "installation": {
      "id": "installation",
      "category": "install",
      "status": "ok",
      "summary": "installation looks consistent",
      "details": {
        "PATH codex #1": "/home/seb/.nvm/versions/node/v26.3.0/bin/codex",
        "current executable": "/home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/bin/codex",
        "install context": "npm (package /home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl, bin /home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/bin, resources /home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/codex-resources, path /home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/codex-path)",
        "managed by bun": "false",
        "managed by npm": "true",
        "managed package root": "/home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex",
        "npm update target": "/home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex"
      },
      "remediation": null,
      "durationMs": 147
    },
    "mcp.config": {
      "id": "mcp.config",
      "category": "mcp",
      "status": "ok",
      "summary": "no MCP servers configured",
      "details": {},
      "remediation": null,
      "durationMs": 0
    },
    "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 404)",
        "reachability mode": "ChatGPT auth"
      },
      "remediation": null,
      "durationMs": 237
    },
    "network.websocket_reachability": {
      "id": "network.websocket_reachability",
      "category": "websocket",
      "status": "ok",
      "summary": "Responses WebSocket handshake succeeded",
      "details": {
        "DNS": "2 IPv4, 2 IPv6, first IPv6",
        "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": 707
    },
    "runtime.provenance": {
      "id": "runtime.provenance",
      "category": "runtime",
      "status": "ok",
      "summary": "running npm on linux-x86_64",
      "details": {
        "commit": "unknown",
        "current executable": "/home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/bin/codex",
        "install method": "npm (package /home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl, bin /home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/bin, resources /home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/codex-resources, path /home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/codex-path)",
        "platform": "linux-x86_64",
        "version": "0.143.0"
      },
      "remediation": null,
      "durationMs": 0
    },
    "runtime.search": {
      "id": "runtime.search",
      "category": "search",
      "status": "ok",
      "summary": "search is OK (bundled)",
      "details": {
        "search command": "/home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex/node_modules/@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/codex-path/rg",
        "search command readiness": "file exists",
        "search provider": "bundled"
      },
      "remediation": null,
      "durationMs": 0
    },
    "sandbox.helpers": {
      "id": "sandbox.helpers",
      "category": "sandbox",
      "status": "ok",
      "summary": "sandbox configuration is readable",
      "details": {
        "approval policy": "OnRequest",
        "codex-linux-sandbox helper": "/home/seb/.codex/tmp/arg0/codex-arg0VJihLX/codex-linux-sandbox",
        "execve wrapper helper": "/home/seb/.codex/tmp/arg0/codex-arg0VJihLX/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": "/home/seb/.codex (dir)",
        "active rollout files": "54 files, 153403743 total bytes, 2840810 average bytes",
        "archived rollout files": "1 files, 27089637 total bytes, 27089637 average bytes",
        "goals DB": "/home/seb/.codex/goals_1.sqlite (file)",
        "goals DB integrity": "ok",
        "log DB": "/home/seb/.codex/logs_2.sqlite (file)",
        "log DB integrity": "ok",
        "log dir": "/home/seb/.codex/log (missing)",
        "memories DB": "/home/seb/.codex/memories_1.sqlite (file)",
        "memories DB integrity": "ok",
        "sqlite home": "/home/seb/.codex (dir)",
        "state DB": "/home/seb/.codex/state_5.sqlite (file)",
        "state DB integrity": "ok"
      },
      "remediation": null,
      "durationMs": 299
    },
    "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": "54",
        "rollout DB active rows": "54",
        "rollout DB archive mismatches": "0",
        "rollout DB archived files": "1",
        "rollout DB archived rows": "1",
        "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=55",
        "rollout DB rows": "55",
        "rollout DB scan cap reached": "false",
        "rollout DB scan errors": "0",
        "rollout DB sources": "cli=54, subagent:review=1",
        "rollout DB stale rows": "0"
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      "remediation": null,
      "durationMs": 3730
    },
    "system.environment": {
      "id": "system.environment",
      "category": "system",
      "status": "ok",
      "summary": "OS language en-US",
      "details": {
        "EDITOR": "not set",
        "LANG": "en_US.UTF-8",
        "VISUAL": "not set",
        "os": "Ubuntu 26.4.0 (resolute) [64-bit]",
        "os language": "en-US",
        "os type": "Ubuntu",
        "os version": "26.4.0"
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      "remediation": null,
      "durationMs": 24
    },
    "terminal.env": {
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      "category": "terminal",
      "status": "ok",
      "summary": "terminal metadata was detected",
      "details": {
        "COLORTERM": "truecolor",
        "SSH_CLIENT": "present",
        "SSH_CONNECTION": "present",
        "SSH_TTY": "present",
        "TERM": "xterm-256color",
        "color output": "enabled",
        "effective locale": "en_US.UTF-8",
        "stderr is terminal": "true",
        "stdin is terminal": "true",
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      "details": {
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        "terminal title items": "activity, project-name",
        "terminal title project source": "git repo root",
        "terminal title project value": "seb",
        "terminal title source": "default"
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      "remediation": null,
      "durationMs": 0
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    "updates.status": {
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      "category": "updates",
      "status": "ok",
      "summary": "update configuration is locally consistent",
      "details": {
        "cached latest version": "0.143.0",
        "check for update on startup": "true",
        "last checked at": "2026-07-09T02:19:51.256678201Z",
        "latest version": "0.143.0",
        "latest version status": "current version is not older",
        "npm update target": "/home/seb/.nvm/versions/node/v26.3.0/lib/node_modules/@openai/codex",
        "update action": "npm install -g @openai/codex",
        "version cache": "/home/seb/.codex/version.json"
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      "remediation": null,
      "durationMs": 595
    }
  }
}

What issue are you seeing?

Every invocation of the exec/shell tool (starting with a trivial pwd) fails with "unsupported call: exec_command" — at one point the error string appeared doubled as "unsupported call: exec_commandexec_command". This occurred both in normal approval mode and in --dangerously-bypass-approvals-and-sandbox (YOLO) mode, ruling out sandbox/approval config as the cause.

codex features list showed both shell_tool and unified_exec set to stable: true simultaneously. Disabling shell_tool (codex features disable shell_tool) and restarting fully resolved it for one session — pwd executed and returned correct output.

However, in later sessions (same config, shell_tool still disabled, unified_exec still enabled), the model instead reports "no shell/command runner tool is available in this session" — a different failure mode (tool absent vs tool rejected) — recurring across:

• fresh sessions (not resumed)
• both gpt-5.5 and gpt-5.4
• before and after a mid-session model switch (which triggered a "Context compacted" event, after which the tool became unavailable for the rest of that session)

No custom model_providers or wire_api overrides are configured — using default ChatGPT sign-in auth.

What steps can reproduce the bug?

Uploaded thread: 019f44f4-f381-7c92-9718-13df9f628992

What is the expected behavior?

The shell/exec tool should be reliably available for every turn within a session once the client reports it as a supported capability, and should not silently disappear or become unavailable following a model switch or context compaction event.

Additional information

Possibly related to #31665, #31664, #30902, and #26977, which report similar "unsupported call" / MCP tool-routing failures on recent Codex CLI builds.