CLI Creator

CLI Creator

Create a real CLI that future Codex threads can run by command name from any working directory.

This skill is for durable tools, not one-off scripts. If a short script in the current repo solves the task, write the script there instead.

Start

Name the target tool, its source, and the first real jobs it should do:

• Source: API docs, OpenAPI JSON, SDK docs, curl examples, browser app, existing internal script, article, or working shell history.
• Jobs: literal reads/writes such as list drafts, download failed job logs, search messages, upload media, read queue schedule.
• Install name: a short binary name such as ci-logs, slack-cli, sentry-cli, or buildkite-logs.

Prefer a new folder under ~/code/clis/<tool-name> when the user wants a personal tool and has not named a repo.

Before scaffolding, check whether the proposed command already exists:

command -v <tool-name> || true

If it exists, choose a clearer install name or ask the user.

Choose the Runtime

Before choosing, inspect the user's machine and source material:

command -v cargo rustc node pnpm npm python3 uv || true

Then choose the least surprising toolchain:

• Consider Rust when a standalone compiled CLI is useful: one fast binary, strong argument parsing, good JSON handling, easy copy/install into ~/.local/bin.
• Use TypeScript/Node when the official SDK, auth helper, browser automation library, or existing repo tooling is the reason the CLI can be better.
• Use Python when the source is data science, local file transforms, notebooks, SQLite/CSV/JSON analysis, or Python-heavy admin tooling that can still be installed as a durable command.

Do not pick a language that adds setup friction unless it materially improves the CLI. If the best language is not installed, use the existing task authorization for installation, or choose the next-best installed option; ask only for a genuinely unresolved choice.

State the choice in one sentence before scaffolding, including the reason and the installed toolchain you found.

Command Contract

Sketch the command surface in chat before coding. Include the binary name, discovery commands, resolve or ID-lookup commands, read commands, write commands, raw escape hatch, auth/config choice, and PATH/install command.

When designing the command surface, read references/agent-cli-patterns.md for the expected composable CLI shape.

Build toward this surface:

• tool-name --help shows every major capability.
• tool-name --json doctor verifies config, auth, version, endpoint reachability, and missing setup.
• tool-name init ... stores local config when env-only auth is painful.
• Discovery commands find accounts, projects, workspaces, teams, queues, channels, repos, dashboards, or other top-level containers.
• Resolve commands turn names, URLs, slugs, permalinks, customer input, or build links into stable IDs so future commands do not repeat broad searches.
• Read commands fetch exact objects and list/search collections. Paginated lists support a bounded --limit, cursor, offset, or clearly documented default.
• Write commands do one named action each: create, update, delete, upload, schedule, retry, comment, draft. They accept the narrowest stable resource ID, support --dry-run, draft, or preview first when the service allows it, and do not hide writes inside broad commands such as fix, debug, or auto.
• --json returns stable machine-readable output.
• A raw escape hatch exists: request, tool-call, api, or the nearest honest name.

Do not expose only a generic request command. Give Codex high-level verbs for the repeated jobs.

Document the JSON policy in the CLI README or equivalent: API pass-through versus CLI envelope, success shape, error shape, and one example for each command family. Under --json, errors must be machine-readable and must not contain credentials.

Auth and Config

Support the boring paths first, in this precedence order:

1. Environment variable using the service's standard name, such as GITHUB_TOKEN.
2. User config under ~/.<tool-name>/config.toml or another simple documented path.
3. --api-key or a tool-specific token flag only for explicit one-off tests. Prefer env/config for normal use because flags can leak into shell history or process listings.

Never print full tokens. doctor --json should say whether a token is available, the auth source category (flag, env, config, provider default, or missing), and what setup step is missing.

If the CLI can run without network or auth, make that explicit in doctor --json: report fixture/offline mode, whether fixture data was found, and whether auth is not required for that mode.

For internal web apps sourced from DevTools curls, create sanitized endpoint notes before implementing: resource name, method/path, required headers, auth mechanism, CSRF behavior, request body, response ID fields, pagination, errors, and one redacted sample response. Never commit copied cookies, bearer tokens, customer secrets, or full production payloads.

Use screenshots to infer workflow, UI vocabulary, fields, and confirmation points. Do not treat screenshots as API evidence unless they are paired with a network request, export, docs page, or fixture.