MCP OAuth: redirect_uri changes from 127.0.0.1 during DCR to localhost during authorization
Open 💬 1 comment Opened Jul 3, 2026 by dev-raghvendra
What version of Codex CLI is running?
codex-cli 0.142.5
What subscription do you have?
gpt-go
Which model were you using?
gpt-5.5
What platform is your computer?
Linux 7.0.0-27-generic x86_64 unknown
What terminal emulator and version are you using (if applicable)?
Ghostty
Codex doctor report
{
"schemaVersion": 1,
"generatedAt": "1783092954s since unix epoch",
"overallStatus": "ok",
"codexVersion": "0.142.5",
"checks": {
"app_server.status": {
"id": "app_server.status",
"category": "app-server",
"status": "ok",
"summary": "background server is not running",
"details": {
"control socket": "/home/dev-raghvendra/.codex/app-server-control/app-server-control.sock",
"daemon state dir": "/home/dev-raghvendra/.codex/app-server-daemon",
"mode": "ephemeral",
"pid file": "/home/dev-raghvendra/.codex/app-server-daemon/app-server.pid (missing)",
"settings": "/home/dev-raghvendra/.codex/app-server-daemon/settings.json (missing)",
"status": "not running",
"update-loop pid file": "/home/dev-raghvendra/.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/dev-raghvendra/.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/dev-raghvendra/.codex",
"config.toml": "/home/dev-raghvendra/.codex/config.toml",
"config.toml parse": "ok",
"cwd": "/home/dev-raghvendra",
"enabled feature flags": "shell_tool, unified_exec, shell_snapshot, 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, 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, auto_compaction, remote_compaction_v2, workspace_dependencies",
"feature flag overrides": "none",
"feature flags enabled": "33",
"log dir": "/home/dev-raghvendra/.codex/log",
"mcp servers": "1",
"model": "<default>",
"model provider": "openai",
"sqlite home": "/home/dev-raghvendra/.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/dev-raghvendra",
"selected git": "/usr/bin/git"
},
"remediation": null,
"durationMs": 40
},
"installation": {
"id": "installation",
"category": "install",
"status": "ok",
"summary": "installation looks consistent",
"details": {
"PATH codex #1": "/home/dev-raghvendra/.local/bin/codex",
"current executable": "/home/dev-raghvendra/.codex/packages/standalone/releases/0.142.5-x86_64-unknown-linux-musl/bin/codex",
"install context": "standalone (unix, package /home/dev-raghvendra/.codex/packages/standalone/releases/0.142.5-x86_64-unknown-linux-musl, bin /home/dev-raghvendra/.codex/packages/standalone/releases/0.142.5-x86_64-unknown-linux-musl/bin, resources /home/dev-raghvendra/.codex/packages/standalone/releases/0.142.5-x86_64-unknown-linux-musl/codex-resources, path /home/dev-raghvendra/.codex/packages/standalone/releases/0.142.5-x86_64-unknown-linux-musl/codex-path)",
"managed by bun": "false",
"managed by npm": "false",
"managed package root": "not set"
},
"remediation": null,
"durationMs": 0
},
"mcp.config": {
"id": "mcp.config",
"category": "mcp",
"status": "ok",
"summary": "MCP configuration is locally consistent",
"details": {
"configured servers": "1",
"disabled servers": "0",
"streamable_http servers": "1"
},
"remediation": null,
"durationMs": 1094
},
"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": 483
},
"network.websocket_reachability": {
"id": "network.websocket_reachability",
"category": "websocket",
"status": "ok",
"summary": "Responses WebSocket handshake succeeded",
"details": {
"DNS": "2 IPv4, 1 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": 1348
},
"runtime.provenance": {
"id": "runtime.provenance",
"category": "runtime",
"status": "ok",
"summary": "running standalone on linux-x86_64",
"details": {
"commit": "unknown",
"current executable": "/home/dev-raghvendra/.codex/packages/standalone/releases/0.142.5-x86_64-unknown-linux-musl/bin/codex",
"install method": "standalone (unix, package /home/dev-raghvendra/.codex/packages/standalone/releases/0.142.5-x86_64-unknown-linux-musl, bin /home/dev-raghvendra/.codex/packages/standalone/releases/0.142.5-x86_64-unknown-linux-musl/bin, resources /home/dev-raghvendra/.codex/packages/standalone/releases/0.142.5-x86_64-unknown-linux-musl/codex-resources, path /home/dev-raghvendra/.codex/packages/standalone/releases/0.142.5-x86_64-unknown-linux-musl/codex-path)",
"platform": "linux-x86_64",
"version": "0.142.5"
},
"remediation": null,
"durationMs": 0
},
"runtime.search": {
"id": "runtime.search",
"category": "search",
"status": "ok",
"summary": "search is OK (bundled)",
"details": {
"search command": "/home/dev-raghvendra/.codex/packages/standalone/releases/0.142.5-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/dev-raghvendra/.codex/tmp/arg0/codex-arg07m1hij/codex-linux-sandbox",
"execve wrapper helper": "/home/dev-raghvendra/.codex/tmp/arg0/codex-arg07m1hij/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/dev-raghvendra/.codex (dir)",
"active rollout files": "14 files, 2411049 total bytes, 172217 average bytes",
"archived rollout files": "0 files, 0 total bytes, 0 average bytes",
"goals DB": "/home/dev-raghvendra/.codex/goals_1.sqlite (file)",
"goals DB integrity": "ok",
"log DB": "/home/dev-raghvendra/.codex/logs_2.sqlite (file)",
"log DB integrity": "ok",
"log dir": "/home/dev-raghvendra/.codex/log (missing)",
"memories DB": "/home/dev-raghvendra/.codex/memories_1.sqlite (file)",
"memories DB integrity": "ok",
"sqlite home": "/home/dev-raghvendra/.codex (dir)",
"standalone release cache": "1 entries in /home/dev-raghvendra/.codex/packages/standalone/releases",
"state DB": "/home/dev-raghvendra/.codex/state_5.sqlite (file)",
"state DB integrity": "ok"
},
"remediation": null,
"durationMs": 498
},
"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": "14",
"rollout DB active rows": "14",
"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=14",
"rollout DB rows": "14",
"rollout DB scan cap reached": "false",
"rollout DB scan errors": "0",
"rollout DB sources": "cli=14",
"rollout DB stale rows": "0"
},
"remediation": null,
"durationMs": 102
},
"system.environment": {
"id": "system.environment",
"category": "system",
"status": "ok",
"summary": "OS language en-US",
"details": {
"EDITOR": "not set",
"LANG": "en_US.UTF-8",
"LESS": "set",
"PAGER": "set",
"VISUAL": "not set",
"os": "Ubuntu 26.4.0 (resolute) [64-bit]",
"os language": "en-US",
"os type": "Ubuntu",
"os version": "26.4.0"
},
"remediation": null,
"durationMs": 16
},
"terminal.env": {
"id": "terminal.env",
"category": "terminal",
"status": "ok",
"summary": "terminal metadata was detected",
"details": {
"COLORTERM": "truecolor",
"DISPLAY": "present",
"WAYLAND_DISPLAY": "present",
"color output": "enabled",
"effective locale": "en_US.UTF-8",
"stderr is terminal": "true",
"stdin is terminal": "true",
"stdout is terminal": "true",
"terminal": "VTE",
"terminal size": "180x28",
"terminal version": "8400"
},
"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": "dev-raghvendra",
"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": "0.142.5",
"check for update on startup": "true",
"last checked at": "2026-07-03T15:23:25.879886784Z",
"latest version": "0.142.5",
"latest version status": "current version is not older",
"update action": "standalone installer",
"version cache": "/home/dev-raghvendra/.codex/version.json"
},
"remediation": null,
"durationMs": 637
}
}
}
~ ❯ at 21:05:54What issue are you seeing?
Codex registers:
http://127.0.0.1:39053/callback/BKj9umzr4ef_
but then sends:
http://localhost:39053/callback/BKj9umzr4ef_
in the /authorize request.
The host changes from 127.0.0.1 to localhost while the port and path remain identical.
This causes OAuth servers performing exact redirect URI validation to reject the authorization request because the URI no longer matches the registered redirect URI.
What steps can reproduce the bug?
- Configure a remote MCP server using OAuth with Dynamic Client Registration.
- Start
codex mcp login <server>. - Observe the registration request and the authorization request.
What is the expected behavior?
The redirect_uri used in the /authorize request should exactly match one of the URIs registered via Dynamic Client Registration.
Additional information
Registration payload
{
"client_name": "Codex",
"redirect_uris": [
"http://127.0.0.1:39053/callback/BKj9umzr4ef_"
],
"grant_types": [
"authorization_code",
"refresh_token"
],
"token_endpoint_auth_method": "none",
"response_types": [
"code"
],
"scope": "read write"
}
Authorization request
redirect_uri=http://localhost:39053/callback/BKj9umzr4ef_
This issue has 1 comment on GitHub. Read the full discussion on GitHub ↗