Dropped app-server events corrupt resumed Codex sessions

What version of Codex CLI is running?

codex-cli 0.147.0

What subscription do you have?

$20/mo

Which model were you using?

gpt-5.6-sol

What platform is your computer?

Darwin 25.0.0 arm64 arm

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

Ghostty 1.2.0; no multiplexer

Codex doctor report

{
  "schemaVersion": 1,
  "generatedAt": "1786558899s since unix epoch",
  "overallStatus": "ok",
  "codexVersion": "0.147.0",
  "checks": {
    "app_server.status": {
      "id": "app_server.status",
      "category": "app-server",
      "status": "ok",
      "summary": "background server is not running",
      "details": {
        "control socket": "/Users/REDACTED/.codex/app-server-control/app-server-control.sock",
        "daemon state dir": "/Users/REDACTED/.codex/app-server-daemon",
        "mode": "ephemeral",
        "pid file": "/Users/REDACTED/.codex/app-server-daemon/app-server.pid (missing)",
        "settings": "/Users/REDACTED/.codex/app-server-daemon/settings.json (missing)",
        "status": "not running",
        "update-loop pid file": "/Users/REDACTED/.codex/app-server-daemon/app-server-updater.pid (missing)"
      },
      "remediation": null,
      "durationMs": 6
    },
    "auth.credentials": {
      "id": "auth.credentials",
      "category": "auth",
      "status": "ok",
      "summary": "auth is configured",
      "details": {
        "auth file": "/Users/REDACTED/.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/REDACTED/.codex",
        "config.toml": "/Users/REDACTED/.codex/config.toml",
        "config.toml parse": "ok",
        "cwd": "/Users/REDACTED/mystuff/Coding/cascade-browser",
        "enabled feature flags": "shell_tool, view_image, 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, in_app_updates, browser_use, browser_use_full_cdp_access, browser_use_external, computer_use, remote_plugin, plugin_sharing, image_generation, resize_all_images, item_ids, skill_mcp_dependency_install, skill_search, mentions_v2, steer, guardian_approval, goals, collaboration_modes, tool_call_mcp_elicitation, auth_elicitation, personality, fast_mode, tui_app_server, remote_compaction_v2, workspace_dependencies",
        "feature flag overrides": "none",
        "feature flags enabled": "39",
        "log dir": "/Users/REDACTED/.codex/log",
        "mcp servers": "2",
        "model": "gpt-5.6-luna",
        "model provider": "openai",
        "sqlite home": "/Users/REDACTED/.codex"
      },
      "remediation": null,
      "durationMs": 1
    },
    "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": "master",
        "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": "/Applications/Xcode.app/Contents/Developer/usr/libexec/git-core",
        "git version": "git version 2.50.1 (Apple Git-155)",
        "repo detected": "true",
        "repo root": "/Users/REDACTED/mystuff/Coding/cascade-browser",
        "selected git": "/usr/bin/git"
      },
      "remediation": null,
      "durationMs": 1515
    },
    "installation": {
      "id": "installation",
      "category": "install",
      "status": "ok",
      "summary": "installation looks consistent",
      "details": {
        "PATH codex #1": "/opt/homebrew/bin/codex",
        "current executable": "/opt/homebrew/lib/node_modules/@openai/codex/node_modules/@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin/bin/codex",
        "install context": "npm (package /opt/homebrew/lib/node_modules/@openai/codex/node_modules/@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin, bin /opt/homebrew/lib/node_modules/@openai/codex/node_modules/@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin/bin, resources /opt/homebrew/lib/node_modules/@openai/codex/node_modules/@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin/codex-resources, path /opt/homebrew/lib/node_modules/@openai/codex/node_modules/@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin/codex-path)",
        "managed by bun": "false",
        "managed by npm": "true",
        "managed by pnpm": "false",
        "managed package root": "/opt/homebrew/lib/node_modules/@openai/codex",
        "npm update target": "/opt/homebrew/lib/node_modules/@openai/codex"
      },
      "remediation": null,
      "durationMs": 1738
    },
    "mcp.config": {
      "id": "mcp.config",
      "category": "mcp",
      "status": "ok",
      "summary": "MCP configuration is locally consistent",
      "details": {
        "configured servers": "2",
        "disabled servers": "1",
        "stdio servers": "2"
      },
      "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 403)",
        "reachability mode": "ChatGPT auth"
      },
      "remediation": null,
      "durationMs": 1733
    },
    "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": 2412
    },
    "runtime.provenance": {
      "id": "runtime.provenance",
      "category": "runtime",
      "status": "ok",
      "summary": "running npm on macos-aarch64",
      "details": {
        "commit": "unknown",
        "current executable": "/opt/homebrew/lib/node_modules/@openai/codex/node_modules/@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin/bin/codex",
        "install method": "npm (package /opt/homebrew/lib/node_modules/@openai/codex/node_modules/@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin, bin /opt/homebrew/lib/node_modules/@openai/codex/node_modules/@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin/bin, resources /opt/homebrew/lib/node_modules/@openai/codex/node_modules/@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin/codex-resources, path /opt/homebrew/lib/node_modules/@openai/codex/node_modules/@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin/codex-path)",
        "platform": "macos-aarch64",
        "version": "0.147.0"
      },
      "remediation": null,
      "durationMs": 0
    },
    "runtime.search": {
      "id": "runtime.search",
      "category": "search",
      "status": "ok",
      "summary": "search is OK (bundled)",
      "details": {
        "search command": "/opt/homebrew/lib/node_modules/@openai/codex/node_modules/@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin/codex-path/rg",
        "search command readiness": "file exists",
        "search provider": "bundled"
      },
      "remediation": null,
      "durationMs": 17
    },
    "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/REDACTED/.codex/tmp/arg0/codex-arg0msOPmE/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/REDACTED/.codex (dir)",
        "active rollout files": "128 files, 211775217 total bytes, 1654493 average bytes",
        "archived rollout files": "0 files, 0 total bytes, 0 average bytes",
        "goals DB": "/Users/REDACTED/.codex/goals_1.sqlite (file)",
        "goals DB integrity": "ok",
        "log DB": "/Users/REDACTED/.codex/logs_2.sqlite (file)",
        "log DB integrity": "ok",
        "log dir": "/Users/REDACTED/.codex/log (dir)",
        "memories DB": "/Users/REDACTED/.codex/memories_1.sqlite (file)",
        "memories DB integrity": "ok",
        "queue DB": "/Users/REDACTED/.codex/queue_1.sqlite (file)",
        "queue DB integrity": "ok",
        "sqlite home": "/Users/REDACTED/.codex (dir)",
        "state DB": "/Users/REDACTED/.codex/state_5.sqlite (file)",
        "state DB integrity": "ok",
        "thread history DB": "/Users/REDACTED/.codex/thread_history_1.sqlite (file)",
        "thread history DB integrity": "ok"
      },
      "remediation": null,
      "durationMs": 3540
    },
    "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": "128",
        "rollout DB active rows": "128",
        "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=128",
        "rollout DB rows": "128",
        "rollout DB scan cap reached": "false",
        "rollout DB scan errors": "0",
        "rollout DB sources": "exec=47, subagent:thread_spawn=39, cli=18, vscode=17, subagent:other=7",
        "rollout DB stale rows": "0"
      },
      "remediation": null,
      "durationMs": 2253
    },
    "system.environment": {
      "id": "system.environment",
      "category": "system",
      "status": "ok",
      "summary": "OS language en-US",
      "details": {
        "EDITOR": "set",
        "GH_PAGER": "set",
        "GIT_PAGER": "set",
        "LANG": "C.UTF-8",
        "LC_ALL": "C.UTF-8",
        "LC_CTYPE": "C.UTF-8",
        "PAGER": "set",
        "VISUAL": "not set",
        "os": "Mac OS 26.0.1 [64-bit]",
        "os language": "en-US",
        "os type": "Mac OS",
        "os version": "26.0.1"
      },
      "remediation": null,
      "durationMs": 127
    },
    "terminal.env": {
      "id": "terminal.env",
      "category": "terminal",
      "status": "ok",
      "summary": "terminal metadata was detected",
      "details": {
        "COLORTERM": "present",
        "NO_COLOR": "1",
        "TERMINFO": "/Applications/Ghostty.app/Contents/Resources/terminfo (dir)",
        "TERM_PROGRAM": "ghostty",
        "color output": "disabled (NO_COLOR)",
        "effective locale": "C.UTF-8",
        "stderr is terminal": "false",
        "stdin is terminal": "false",
        "stdout is terminal": "false",
        "terminal": "Ghostty",
        "terminal size": "80x24",
        "terminal version": "1.2.0"
      },
      "remediation": null,
      "durationMs": 70
    },
    "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": "cascade-browser",
        "terminal title source": "default"
      },
      "remediation": null,
      "durationMs": 1
    },
    "updates.status": {
      "id": "updates.status",
      "category": "updates",
      "status": "ok",
      "summary": "update configuration is locally consistent",
      "details": {
        "cached latest version": "0.147.0",
        "check for update on startup": "true",
        "last checked at": "2026-08-12T00:12:12.876114Z",
        "latest version": "0.147.0",
        "latest version status": "current version is not older",
        "npm update target": "/opt/homebrew/lib/node_modules/@openai/codex",
        "update action": "npm install -g @openai/codex",
        "version cache": "/Users/REDACTED/.codex/version.json"
      },
      "remediation": null,
      "durationMs": 1731
    }
  }
}

What issue are you seeing?

A long-running codex exec resume --json session emitted repeated app-server lag errors and dropped hundreds of events. Later attempts to resume the same session could not continue because a custom tool-call result was missing. The process stayed alive and repeatedly printed the same error without producing a response.

What steps can reproduce the bug?

1. Start or resume a Codex session through codex exec resume --json.
2. Let the session perform a long-running workflow with repeated tool calls and polling.
3. Allow the in-process app-server event consumer to fall behind.
4. Observe event-drop errors.
5. Resume the same Codex session with another prompt.

What is the expected behavior?

Expected behavior

Event-stream backpressure should not permanently corrupt session state. If events must be dropped, Codex should preserve required tool-call/result pairs, recover the missing state, or terminate the turn with a clear retryable error. A resumed session should not wait indefinitely for an output that can never arrive.

Additional information

Actual behavior

The original run emitted many errors in this form:

in-process app-server event stream lagged; dropped 43 events
in-process app-server event stream lagged; dropped 171 events
in-process app-server event stream lagged; dropped 854 events

Afterward, every resumed run repeatedly emitted:

ERROR codex_core::util: Custom tool call output is missing for call id: call_lgAAyVMavptKZY5NFEwPIkAo

The resumed process produced no assistant response and remained stuck until canceled. Starting additional turns on that same session reproduced the missing-output error.

Impact

• The session becomes unusable across subsequent resumes.
• The harness sees a live process but receives no meaningful assistant output.
• User prompts queue behind or repeatedly re-enter the broken session.
• Recovery currently requires abandoning or rotating the session rather than simply retrying the turn.

Relevant timing

• Event-drop burst began: 2026-08-12 17:58:29 UTC
• First missing tool-output error after resume: 2026-08-12 17:59:53 UTC
• Error continued across another resumed run through at least 2026-08-12 18:05:56 UTC

Start by tracing the app-server event flow and the resumed Codex session path described in the issue. Reproduce a session with dropped app-server events, then verify that resuming it preserves the complete event history without corruption.