https://gpt-world.com/Twelve source-checked Codex CLI lessons, followed by six companion OpenAI Platform architecture guides.enSun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/install-and-diagnose/https://gpt-world.com/guides/install-and-diagnose/A reliable Codex workflow starts before the first prompt. Install from the official standalone script, identify the binary you are actually running, update deliberately, and use the built-in diagnostic report instead of guessing about configuration, authentication, Git, or terminal failures.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/authentication-and-credentials/https://gpt-world.com/guides/authentication-and-credentials/Codex supports ChatGPT sign-in for subscription access and API-key sign-in for usage-based local work. The safe path is to choose the flow deliberately, pipe secrets through stdin, verify the active method, and treat local auth storage like a password.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/first-terminal-session/https://gpt-world.com/guides/first-terminal-session/The first useful Codex session begins in the right repository with a bounded permission mode and a prompt that states goal, context, constraints, and done condition. Codex can explore, edit, run checks, and report evidence, but only when the task boundary is explicit.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/sandbox-approvals-network/https://gpt-world.com/guides/sandbox-approvals-network/Codex security is the combination of an OS-enforced sandbox and an approval policy. Workspace-write with on-request approvals is a practical local default; read-only is for inspection and planning. Web search does not automatically grant network access to spawned commands.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/interactive-session-control/https://gpt-world.com/guides/interactive-session-control/Codex CLI exposes keyboard-first controls for live work plus top-level commands for saved-session lifecycle. Plan mode improves ambiguous work; status and diff expose state; compact preserves key context; review creates a dedicated inspection pass. Resume, fork, archive, unarchive, and permanent delete keep persisted work explicit.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/agents-md-guidance/https://gpt-world.com/guides/agents-md-guidance/Codex reads an instruction chain before work begins: global guidance, then project files from repository root toward the working directory. Closer guidance appears later and overrides broader guidance. AGENTS.override.md wins at a level, and the combined project guidance has a default size limit.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/config-profiles-models/https://gpt-world.com/guides/config-profiles-models/Codex resolves configuration from command-line overrides, trusted project layers, a selected profile, user config, system config, then built-in defaults. Profiles are separate files, and current model availability should be inspected live rather than frozen into evergreen advice.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/diff-test-review/https://gpt-world.com/guides/diff-test-review/Codex can implement, run checks, show the working-tree diff, and launch a dedicated reviewer. Review scopes are mutually exclusive: uncommitted work, a base-branch comparison, a commit, or custom instructions. The reviewer reports findings without changing the tree.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/mcp-connections/https://gpt-world.com/guides/mcp-connections/Codex supports local STDIO and Streamable HTTP MCP servers. CLI, IDE extension, and desktop app share host configuration. A reliable connection names its transport, authentication source, timeouts, required status, enabled tools, and approval behavior before a workflow depends on it.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/skills-and-plugins/https://gpt-world.com/guides/skills-and-plugins/Skills package instructions, references, scripts, and optional assets. Codex discovers them through concise metadata and loads full instructions only when selected. Plugins distribute skills and optional MCP connections through configured marketplaces; list and review a marketplace before installing a named plugin.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/hooks-and-rules/https://gpt-world.com/guides/hooks-and-rules/Hooks run trusted command handlers at lifecycle events such as PreToolUse, PostToolUse, Stop, and SessionStart. Rules decide whether matching command prefixes are allowed, prompted, or forbidden outside the sandbox. Hooks are stable; rules remain experimental and the most restrictive matching decision wins.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/subagents-exec-ci/https://gpt-world.com/guides/subagents-exec-ci/Subagents protect the main thread from noisy exploration and can run independent read-heavy work in parallel. For non-interactive workflows, codex exec defaults to a read-only sandbox, streams progress to stderr, and prints the final message to stdout; JSONL and output schemas support machine consumers. GitHub Actions should use the official action and narrow privileges.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/responses-boundary/https://gpt-world.com/guides/responses-boundary/The Responses API is the recommended starting point for new OpenAI integrations. Treat it as an application boundary—not a thin text-generation wrapper—so messages, tool calls, tool results, and future input types remain explicit.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/tool-contracts/https://gpt-world.com/guides/tool-contracts/OpenAI tools can search, retrieve files, execute code, connect through MCP, or call your own functions. Reliability comes from the boundary around each action: a small schema, explicit authority, idempotency, and a result the model can interpret.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/structured-outputs/https://gpt-world.com/guides/structured-outputs/Structured Outputs can constrain model responses to a supplied JSON Schema. That removes a class of parsing failures, but it does not prove that values are true, useful, authorized, or safe to apply.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/agent-loops/https://gpt-world.com/guides/agent-loops/An agent plans, calls tools, carries state, and may hand work to specialists. The key architecture decision is not how many agents exist—it is who owns the run loop, tool policy, state, approvals, and trace.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/realtime-systems/https://gpt-world.com/guides/realtime-systems/Realtime sessions are designed for low-latency live interactions. A production voice experience is more than streaming audio: it needs a transport chosen for the client, explicit session state, interruption behavior, tool latency budgets, and recovery from partial turns.Sun, 26 Jul 2026 00:00:00 GMThttps://gpt-world.com/guides/model-portability/https://gpt-world.com/guides/model-portability/The OpenAI model catalog changes over time. Product code should ask for a tested capability profile—quality, latency, modalities, tool support, and budget—then resolve that profile through configuration and evaluations.Sun, 26 Jul 2026 00:00:00 GMT