---
title: "Codex use cases: 23 real examples"
canonical: "https://agenticfeats.com/agents/codex/"
receipts: 23
shown: 14
page: 1
pages: 1
---

> From Agentic Feats: sourced examples of AI agents at work. Map of the site for agents: https://agenticfeats.com/llms.txt

# Codex use cases: 23 real examples

Agentic Feats lists 23 sourced examples of Codex in real work; 14 link the artifact; most common job type: coding (9). Newest first.

## Feats, newest first

- [Parallel feature shipping in Codex](https://agenticfeats.com/c/parallel-feature-shipping-in-codex.md) (Codex; Shown; 2026-10-13): Keith Rumjahn used the OpenAI Codex desktop app with git worktrees and parallel threads to build four features for their Mac app at once. Result: Four features finished in about 2 hours instead of 3-5 days each, and the daily view took 40 minutes.
- [S-Corp taxes with two agents](https://agenticfeats.com/c/s-corp-taxes-with-two-agents-claude-code.md) (Claude Code, Codex; Claim; 2026-10-13): Claude Code wrote Python scripts that compute the author's S-Corp tax forms from QuickBooks and bank data, while Codex reviewed the code. Result: Codex caught real errors, including a wrong Schedule L field mapping, and the author found their own 2025 mistakes.
- [Codex agent as company employee](https://agenticfeats.com/c/codex-agent-as-company-employee.md) (Codex; Claim; 2026-10-13): The author built an autonomous agent from Codex, ChatGPT Plus, systemd, and UNIX email and user accounts, and uses it like an employee. Result: The agent handles all kinds of tasks for their company, and the author reports no memory problems so far.
- [Amazon subscription refund](https://agenticfeats.com/c/amazon-subscription-refund-codex.md) (Codex; Shown; 2026-10-13): Codex running GPT-5.5 cancelled an Amazon subscription, opened the live chat with an associate, and argued for an immediate refund. Result: The associate confirmed the refund and the author got $15 back within about five minutes, while the author watched it happen.
- [Codex email audit and trip site](https://agenticfeats.com/c/codex-email-audit-and-trip-site.md) (Codex; Shown; 2026-10-13): Codex, driven by two authors, audited a month of missed emails, built a vacation planning site from a phone, and shopped for a dishwasher. Result: Codex returned a complete, classified list of missed email threads where Claude missed many; it also deployed a vacation site researched from hotel availability.
- [Client notes to Belmond shortlist](https://agenticfeats.com/c/client-notes-to-belmond-shortlist-codex.md) (Codex; Numbers; 2026-10-13): Codex Desktop read a client notes Word doc, checked Belmond's live booking site, and built a three-option comparison matching the client's past trip preferences. Result: Codex returned a ranked comparison of three Belmond properties with availability and nightly rate ranges for a sample window, plus a more detailed Word doc.
- [Research workflow automation with Codex](https://agenticfeats.com/c/research-workflow-automation-with-codex.md) (Codex; Claim; 2026-10-13): Codex runs a weekly arXiv search, triages new papers, feeds a Zotero library, and turns hypotheses into cheap experiment tests for an AI safety researcher. Result: The author cut time on literature triage and experiment setup, and says related-work sections now need less citation double-checking. No numbers are given.
- [Comms tasks with Codex](https://agenticfeats.com/c/comms-tasks-with-codex.md) (Codex; Numbers; 2026-10-13): The author used OpenAI's Codex to build a PR coverage dashboard, sort a messy work folder, and filter a recipe site for picky kids. Result: Codex sorted 240 dinner recipes down to 62 family-fit picks, rated them, and produced an index, a spreadsheet, and a Google Drive folder.
- [Slack issue triage to Codex fix](https://agenticfeats.com/c/slack-issue-triage-to-codex-fix.md) (Codex, Custom agent; Numbers; 2026-10-13): An internal ops agent triaged a Slack issue, passed it to a Codex agent, and then verified the fix back in Slack. Result: The Codex agent resolved the issue in 40 minutes, and the ops agent confirmed the fix in Slack.
- [Self-hosted agentic software factory](https://agenticfeats.com/c/self-hosted-agentic-software-factory-hermes-agent.md) (Codex, Hermes Agent; Shown; 2026-10-13): The author built a sandboxed home server stack where Hermes with Codex takes one prompt and runs the whole software lifecycle, from repo to deployment. Result: From one prompt it created a repo, wrote the app and tests, got CI green, provisioned Postgres and deployed behind HTTPS with no further messages.
- [VNC client build attempts](https://agenticfeats.com/c/vnc-client-build-attempts-claude-code.md) (Claude Code, Codex; Shown; 2026-10-13): The author asked Claude, then ChatGPT 5.6 Sol, to build a bare-bones VNC viewer for Windows 10 that avoids dropped keystrokes. Result: Claude gave failed builds for a week and used up the 20x Max weekly limit. Sol had worked 20+ hours without success.
- [Find why a process dies](https://agenticfeats.com/c/find-why-a-process-dies-codex.md) (Codex; Claim; 2026-10-13): Codex CLI, run on the author's Mac, connected to their Ubuntu server over SSH and checked kernel logs to find why Claude Code kept dying. Result: Codex traced the kills to the Linux OOM killer on a 2 GB droplet with no swap, and listed fixes without changing anything.
- [AI bookkeeping for Swedish companies](https://agenticfeats.com/c/ai-bookkeeping-for-swedish-companies-claude-code.md) (Claude Code, Codex; Numbers; 2026-10-13): Claude Code and Codex kept the books for several Swedish limited companies over ten weeks, handling receipts, VAT, bank matching and posting. Result: About 1,570 entries posted in Claude Code alone, and Codex caught a VAT return error days before filing.
- [Substack stats report in Codex](https://agenticfeats.com/c/substack-stats-report-in-codex.md) (Codex; Shown; 2026-10-13): Codex used Computer Use to open the author's Substack dashboard and pull figures for every published post into a newsletter report. Result: The author uses Codex daily for reports, editable designs, video editing and this newsletter, which still needed plenty of corrections.
- [Faster Rust ML code via benchmarks](https://agenticfeats.com/c/faster-rust-ml-code-via-benchmarks-codex.md) (Codex, Other; Shown; 2026-10-13): Coding agents wrote Rust ML algorithms like UMAP from scratch, then iteratively optimized them against criterion benchmarks. Result: Each model pass added about 1.5x to 2.0x speedup, reaching roughly 7.5x to 32x over baseline; one implementation beat xgboost on speed.
- [Ableton Live MCP for Codex](https://agenticfeats.com/c/ableton-live-mcp-for-codex.md) (Codex; Shown; 2026-10-13): The author built an MCP server so Codex can control Ableton Live, including running Python inside Live. Result: Codex built a full EDM track and a piano duet from scratch in minutes in Ableton, shown in two demo videos with the prompts listed.
- [Three agents build multiplayer Counter Strike](https://agenticfeats.com/c/three-agents-build-multiplayer-counter-strike-codex.md) (Claude Code, Codex, Gemini agent; Shown; 2026-10-13): The Instant team gave Codex, Claude Opus 4.5 and Gemini 3 Pro the same prompts to build a 3D multiplayer Counter Strike clone. Result: All three produced a playable multiplayer game with a map list and saved rooms; Opus won on visuals, Gemini on backend, Codex landed in between.
- [Claude Code plays RollerCoaster Tycoon](https://agenticfeats.com/c/claude-code-plays-rollercoaster-tycoon.md) (Claude Code, Codex; Shown; 2026-10-13): Ramp Labs forked OpenRCT2, built a kubectl-style CLI, and let Claude Code manage a theme park through it. Result: Claude handled analytics, pricing, staffing and simple stall placement well, but failed at pathways, large coasters, and vertical terrain. The mod took about 40 hours.
- [SQLite-like engine in Rust](https://agenticfeats.com/c/sqlite-like-engine-in-rust-claude-code.md) (Claude Code, Codex, Other; Shown; 2026-10-13): Claude, Codex, and Gemini workers, two of each, built a SQLite-style database engine in Rust by claiming tasks through git lock files. Result: About 19k lines of Rust across 154 commits in three days. The engine passes 64 SQLLogicTest queries and 282 AI-written unit tests.
- [First personal dinner-planning app](https://agenticfeats.com/c/first-personal-dinner-planning-app-codex.md) (Codex; Shown; 2026-10-13): A non-programmer used Codex to build a local web app that suggests dinners from pantry, garden, dietary rules, appliances and weather. Result: Built a working What's for Dinner app with pantry, garden, recipe and restaurant pages plus a suggestions engine, in under a week.
- [Personal site redesign with Codex](https://agenticfeats.com/c/personal-site-redesign-with-codex.md) (Codex; Shown; 2026-10-13): Codex CLI redesigned the author's personal site after reading a design prompt copied from Anthropic's frontend-design plugin into a local markdown file. Result: The author shipped a redesigned personal site, nearly right in one shot, after a few more iterations.
- [Stolen package refund via Computer Use](https://agenticfeats.com/c/stolen-package-refund-via-computer-use-codex.md) (Codex; Claim; 2026-10-13): Codex with Computer Use waited in Amazon's support queue, polling on a schedule, then pursued a refund for a stolen package. Result: The author showered while Codex waited in the queue and negotiated. The refund was done when they returned.
- [AI chat app on Nokia 110](https://agenticfeats.com/c/ai-chat-app-on-nokia-110-codex.md) (Codex, Custom agent; Shown; 2026-10-13): Codex helped the author reverse-engineer a Nokia 110 4G's firmware and build a native AI chat app with a custom agent. Result: A working prototype runs on the handset over mobile data: typed chat via DeepSeek, battery check, torch, calls and alarms, tested on the phone.