Add an example for config.toml in the repository root

@llk23r - what I am using - hope it helps!

# =========================
# Codex CLI config.toml
# =========================
# Rule: In each "CHOOSE ONE" block, uncomment EXACTLY ONE line.

# -------------------------
# Model (string)
# -------------------------
# CHOOSE ONE:
model = "gpt-5"
# model = "o3"
# model = "o4-mini"

# -------------------------
# Model provider (string)
# -------------------------
# CHOOSE ONE:
model_provider = "openai"
# model_provider = "openai-chat-completions"   # if you define that provider below
# model_provider = "ollama"                     # local
# model_provider = "azure"                      # Azure OpenAI

# -------------------------
# Reasoning effort (string)
# -------------------------
# CHOOSE ONE:
model_reasoning_effort = "high"
# model_reasoning_effort = "medium"
# model_reasoning_effort = "low"
# model_reasoning_effort = "minimal"

# -------------------------
# Reasoning summaries (string)
# -------------------------
# CHOOSE ONE:
model_reasoning_summary = "auto"
# model_reasoning_summary = "concise"
# model_reasoning_summary = "detailed"
# model_reasoning_summary = "none"

# -------------------------
# Verbosity (string)
# -------------------------
# CHOOSE ONE:
model_verbosity = "medium"
# model_verbosity = "low"
# model_verbosity = "high"

# -------------------------
# Force reasoning summaries on non-default combos (bool)
# -------------------------
# CHOOSE ONE:
model_supports_reasoning_summaries = true
# model_supports_reasoning_summaries = false

# -------------------------
# Approval policy (string)
# -------------------------
# CHOOSE ONE:
approval_policy = "on-request"
# approval_policy = "untrusted"
# approval_policy = "on-failure"
# approval_policy = "never"

# -------------------------
# Sandbox mode (string)
# -------------------------
# CHOOSE ONE:
sandbox_mode = "danger-full-access"   # no sandbox
# sandbox_mode = "workspace-write"     # writes allowed in cwd/tmp only
# sandbox_mode = "read-only"           # default in docs: no writes, no network

# If you select "workspace-write", you may also configure:
# [sandbox_workspace_write]
# # Writable roots (bool/array) — CHOOSE ONE for each:
# # exclude_tmpdir_env_var = true
# exclude_tmpdir_env_var = false
# # exclude_slash_tmp = true
# exclude_slash_tmp = false
# # Optional additional writable roots:
# # writable_roots = ["/Users/YOU/.pyenv/shims"]
# # Network inside sandbox — CHOOSE ONE:
# # network_access = true
# # network_access = false

# -------------------------
# Response storage (bool)
# -------------------------
# CHOOSE ONE:
disable_response_storage = false
# disable_response_storage = true   # use for ZDR / no caching

# -------------------------
# Shell environment policy
# -------------------------
[shell_environment_policy]
# inherit — CHOOSE ONE:
inherit = "core"
# inherit = "all"
# inherit = "none"

# Keep default secret filtering?
ignore_default_excludes = false

# Drop patterns (array of globs); keep empty if not needed
exclude = ["AWS_*", "AZURE_*"]
# exclude = []

# Force-set environment vars (table); keep empty if not needed
set = { }
# set = { CI = "1" }

# Whitelist patterns (array of globs); empty means no whitelist
include_only = []
# include_only = ["PATH", "HOME"]

# -------------------------
# Providers (optional — define only what you use)
# -------------------------
# [model_providers.openai]
# name = "OpenAI"
# base_url = "https://api.openai.com/v1"
# env_key = "OPENAI_API_KEY"
# # Per-provider network tuning (optional):
# # request_max_retries = 4
# # stream_max_retries = 10
# # stream_idle_timeout_ms = 300000

# [model_providers.openai-chat-completions]
# name = "OpenAI using Chat Completions"
# base_url = "https://api.openai.com/v1"
# env_key = "OPENAI_API_KEY"
# wire_api = "chat"

# [model_providers.azure]
# name = "Azure"
# base_url = "https://YOUR_PROJECT_NAME.openai.azure.com/openai"
# env_key = "AZURE_OPENAI_API_KEY"
# query_params = { api-version = "2025-04-01-preview" }

# [model_providers.ollama]
# name = "Ollama"
# base_url = "http://localhost:11434/v1"

# -------------------------
# MCP servers (optional)
# -------------------------
# [mcp_servers.example]
# command = "npx"
# args = ["-y", "mcp-server"]
# env = { API_KEY = "value" }

# -------------------------
# Profiles (optional)
# -------------------------
# [profiles.default]
# model = "gpt-5"
# model_provider = "openai"
# approval_policy = "on-request"
# model_reasoning_effort = "high"
# model_reasoning_summary = "auto"
# model_verbosity = "medium" 

Thanks a lot for sharing it, @Alfredo-Sandoval! It's pretty comprehensive and looks like most keys are covered! 🙌🏼

I'll also add preferred_auth_method and notify to the list.

An example config.toml was recently added to the documentation.