GitHub Copilot CLI

GitHub Copilot CLI is GitHub's standalone agentic coding agent for the terminal. It replaces the older gh copilot suggest / gh copilot explain extension. The current product installs as @github/copilot (npm), via curl -fsSL https://gh.io/copilot-install | bash, or with Homebrew (brew install --cask copilot-cli). You run a GitHub-native agent in your shell that plans work, edits repositories, opens pull requests, talks to issues through native GitHub MCP, and can fan out parallel subagents with /fleet. This is a breaking mental-model change from 2024-mid-2025 docs. The github/gh-copilot GitHub CLI extension, commands like gh copilot suggest and gh copilot explain, was deprecated on 25 October 2025. If that extension is still installed, remove it with gh extension remove github/gh-copilot and migrate to the standalone Copilot CLI. The new tool is an agentic runtime: /plan to outline work, Shift+Tab to move between plan and autopilot modes, /model to pick models, /delegate to push implementation toward a PR, /resume to continue long sessions, plus skills, AGENTS.md guidance, and MCP (including GitHub-native issue/PR context). Models matter because CLI interactions draw AI Credits. On 9 July 2026 GitHub announced OpenAI's GPT-5.6 Sol, Terra, and Luna in Copilot, including Copilot CLI's model picker. Sol is the high-reasoning tier for large codebases and long agent runs; Terra is the balanced default; Luna is the lightweight, cost-efficient option. Anthropic and Google models are also available in Copilot's broader catalog (subject to plan and admin policy). Copilot Business/Enterprise admins may need to enable GPT-5.6 policies. Sol availability skews to Pro+/Max/Business/Enterprise; Terra and Luna reach Pro and above (plus higher tiers). Access is included with Copilot Free, Pro, Pro+, Max, Business, and Enterprise. Usage is not "unlimited agent loops": each agent interaction consumes GitHub AI Credits from your plan allowance (1 AI credit = $0.01 USD). Individual paid examples as of August 2026 docs: Pro $10/month with 1,500 total monthly AI credits (1,000 base + 500 flex); Pro+ $39/month with 7,000; Max $100/month with 20,000. Free/Student plans include limited AI-credit allowances with auto model selection constraints. Code completions remain outside AI-credit billing on paid plans; Copilot CLI agent work does consume credits. Exceeding the included pool means upgrading, setting an additional-usage budget, or waiting for the monthly UTC reset. On a Mac, Copilot CLI fits terminal-first workflows alongside Ghostty, iTerm2, Warp, or Terminal.app. It can start a /plan in the CLI and continue in VS Code, or stay entirely in the shell for issue-to-commit loops. Native GitHub MCP means the agent can search issues, reason about labels/activity, and /delegate a branch + PR without bolting on a third-party GitHub integration first. Organization guardrails still apply: branch protections, required checks, and Copilot Business/Enterprise policies follow the agent. File edits and command execution are approval-gated, you remain responsible for reviewing /diff output. Competitive set in August 2026: Anthropic Claude Code (terminal/IDE agent on Claude models), OpenAI Codex CLI / Codex-in-ChatGPT, Cursor (AI editor), Warp AI (terminal-bound), Amazon Q CLI (AWS-weighted), and Meta Muse Code (newer terminal agent narrative). Copilot CLI's differentiator is GitHub-native MCP, billing through existing Copilot seats/credits, and deep issue/PR/delegate loops for teams already standardized on GitHub. Who it is for: developers who live in git + GitHub Issues/PRs and want an agent that does not abandon the terminal; teams that already pay for Copilot and want CLI parity with IDE agents; engineers who need /fleet parallelism or multi-model comparison on one task. Who should be careful: anyone still following tutorials that only mention gh copilot suggest (obsolete); orgs whose admins disabled Copilot CLI; users who expect offline operation; people who only need occasional one-liner shell help (the old suggest/explain niche), the new CLI is a heavier agentic product with credit burn to match. Install prerequisites include an active Copilot subscription (or entitled Free access) and, for npm, Node.js 22+. First launch uses /login (or a fine-grained PAT with Copilot Requests via COPILOT_GITHUB_TOKEN / GH_TOKEN / GITHUB_TOKEN). Keep Copilot CLI updated (docs cite minimum versions for accurate usage/billing UI; prefer latest stable). Use /changelog and /experimental show to track preview capabilities. Practically, start with a small /plan on a scratch branch, pick Terra or Luna while learning cost dynamics, enable AGENTS.md with build/test commands, and only then try Sol or /fleet on expensive refactors. Treat autopilot as a power mode after you trust the approval UX. Migrate muscle memory: aliases pointing at gh copilot suggest should be deleted; teach the team the slash-command vocabulary instead. As of 2026-08-09 the product to document is the agentic CLI on @github/copilot: bundled with Copilot plans, metered by AI Credits, with GPT-5.6 Sol, Terra, and Luna in the picker. Retire suggest/explain language from runbooks and onboarding. The github/gh-copilot extension was deprecated on 25 October 2025.