How to Add a GitHub Copilot CLI Agent to Your Floor

GitHub Copilot CLI is now a first-class agent engine in Munder Difflin as of v0.3.3, the project's first community-contributed provider via PR #101 by @anxkhn. Users can install the official npm package @github/copilot, hire a Copilot worker, and choose between Claude Sonnet 4.5 (default), GPT-5.4, or auto mode, with authentication using the existing GitHub Copilot login and no new keys. Copilot runs in print mode (copilot -p), which exits per turn, so workers cannot drain inbox mail and routed mail bounces to the orchestrator instead of dropping.

How to Add a GitHub Copilot CLI Agent to Your Floor A step-by-step v0.3.3 walkthrough: install GitHub Copilot CLI or let the harness install it for you , hire a Copilot worker, pick a model, and know exactly what print mode can and can't do. As of v0.3.3 , GitHub Copilot CLI is a first-class agent engine in Munder Difflin — the project's first community-contributed provider PR 101 by @anxkhn . Install @github/copilot or let the harness's missing-CLI installer do it , hit Add Agent , pick the Copilot engine, choose a model Claude Sonnet 4.5 default, GPT-5.4, or auto , and it authenticates with your existing Copilot login — no new keys . One honest caveat: Copilot runs in print mode copilot -p , which exits per turn, so its workers can't drain inbox mail — routed mail bounces to the orchestrator instead of dropping. Use Copilot workers for dispatched, self-contained tasks . If you already pay for GitHub Copilot, you have an agent engine sitting in your subscription that most people only ever use as autocomplete. Copilot CLI is the terminal version — a real coding agent you run with copilot — and since v0.3.3 /blog/launching-munder-difflin-v0-3-3/ , Munder Difflin can hire it onto the floor next to your Claude Code, Codex, and OpenCode workers. This guide walks the whole path: install, hire, model choice, what auto-mode changes, and the one behavioral caveat you should understand before you assign work. Step 0: have the floor running step-0-have-the-floor-running You need Munder Difflin itself first — if you don’t, the install guide /blog/how-to-install-and-use-munder-difflin/ covers it in a few minutes. Everything below assumes you’re looking at the office floor with Michael seated in his office. Step 1: install Copilot CLI or don’t — the harness will offer step-1-install-copilot-cli-or-dont-the-harness-will-offer The engine drives the official npm package: npm install -g @github/copilot Then log in once with your GitHub account if you haven’t copilot walks you through it on first run . That’s the entire auth story: the engine uses your existing GitHub Copilot login, no new keys , nothing to paste into Settings → AI Engines. You can also skip this step entirely. Munder Difflin has a self-healing installer for missing engine CLIs: if you pick Copilot in Add Agent and the copilot binary isn’t on your PATH , the harness offers the official npm install -g @github/copilot , runs it in the terminal, then auto restarts-and-continues into the freshly installed binary. No dead end, no manual retry. Step 2: Add Agent, pick Copilot step-2-add-agent-pick-copilot Click Add Agent on the floor. The visual provider picker now lists GitHub Copilot CLI alongside the other six engines. Pick it, name your hire, choose a working directory — and if you flip the git-isolation toggle, the agent gets its own dedicated worktree so it never collides with other agents on branches more on why that matters in worktrees vs the hive /blog/claude-code-git-worktrees-vs-hive/ . Here’s the whole hire flow in nineteen seconds: Copilot hires also work through voice — Realtime Michael’s spawn action can hire one — and if you paste a raw copilot ... command into the custom-command field, the harness infers the binary and treats it as a Copilot engine. Step 3: choose a model step-3-choose-a-model The Copilot engine ships with a model picker, COPILOT MODELS , with three options: Claude Sonnet 4.5 — the default. GPT-5.4 — if you’d rather run OpenAI’s model. auto — let Copilot pick per request. Whatever you choose is passed through as --model <id on each turn. This is a per-hire choice, so you can run one Copilot worker on Sonnet and another on GPT-5.4 and compare them on the same board. What auto-mode gates what-auto-mode-gates Under the hood, every turn a Copilot agent takes is Copilot CLI’s documented non-interactive print mode : copilot -p "<prompt " -s --allow-all-tools --no-ask-user --model <id The auto-approval flags — -s --allow-all-tools --no-ask-user — are gated by the floor’s auto-mode toggle , exactly like every other engine. Auto-mode on: Copilot gets its documented allow-all flags and works without stopping to ask permission per tool call. Auto-mode off: the flags are omitted and the agent runs conservatively. The floor-level guardrails — the approvals queue /blog/human-in-the-loop-approving-ai-agents/ , budgets, the circuit breaker — sit above all of that regardless of engine. Session continuity is handled with --resume best-effort : print mode exits after every turn, but the next turn reattaches the prior session, so follow-ups don’t start cold. The honest inbox caveat the-honest-inbox-caveat This is the part worth reading twice. Print mode exits per turn and exposes no hook bridge , which means a Copilot worker can’t do the thing hive-aware engines do: sit idle, notice mail in its inbox, and drain it. The engine is registered as non-hive-aware canReceiveInbox: false on purpose. So what happens when another agent routes a message to your Copilot worker? It bounces to the GOD orchestrator instead of silently dropping. Michael sees the bounced mail and handles or re-routes it — the message survives, it just doesn’t land in a mailbox nobody is checking. If you’re new to how Michael adjudicates traffic, the GOD orchestrator post /blog/how-the-god-orchestrator-works/ explains the routing model. The practical rule: use Copilot workers for dispatched, self-contained tasks. “Take this issue, fix it, report back” is their sweet spot. Long-running conversational back-and-forth between agents is not — hand that to a hive-aware engine. Shipping the limitation honestly, with a bounce path instead of a black hole, was a deliberate design call in PR 101, and it’s the right one. Recap recap npm install -g @github/copilot — or let the missing-CLI installer offer it. Add Agent → pick the Copilot engine → optionally flip git isolation.- Pick a model: Claude Sonnet 4.5 default , GPT-5.4, or auto. - Know the shape: print mode per turn, --resume continuity, auto-mode gates the approval flags. - Assign dispatched, self-contained tasks; let mail-heavy coordination live on hive-aware engines. That’s a seventh engine on your floor, powered by a subscription you already have. Try it try-it Grab the latest build from the releases page https://github.com/chaitanyagiri/munder-difflin/releases/latest — and if the Copilot engine saves you a hire, a star on GitHub https://github.com/chaitanyagiri/munder-difflin is how community contributions like PR 101 keep coming. FAQ Do I need a new API key to run a GitHub Copilot CLI agent in Munder Difflin? No. The Copilot engine authenticates through your existing GitHub Copilot login — the same auth the copilot CLI uses in a plain terminal. There is no BYOK key to paste into Settings for this engine; if you can run copilot in your shell, you can hire it on the floor. What models can a Copilot CLI agent use? The Add Agent flow includes a model picker for the Copilot engine with three options: Claude Sonnet 4.5 the default , GPT-5.4, and auto, which lets Copilot choose. Your selection is passed to the CLI via the --model flag on every turn. Why does my Copilot agent's inbox mail go to the orchestrator instead? By design. Copilot CLI runs in non-interactive print mode, which exits after each turn and exposes no hook bridge, so a Copilot worker cannot sit idle and drain a mailbox. Rather than letting routed mail silently drop, the harness bounces it to the GOD orchestrator, which handles or re-routes it. Use Copilot workers for dispatched, self-contained tasks and they work great. What does the auto-mode toggle change for Copilot agents? In auto mode the harness adds Copilot's auto-approval flags -s --allow-all-tools --no-ask-user so the agent can use tools without stopping to ask. With auto mode off, those flags are omitted and Copilot runs more conservatively — the same gating every other engine on the floor gets. Does a Copilot agent keep context between turns if print mode exits every time? Yes, best-effort. The engine uses Copilot CLI's --resume flag to reattach the previous session on the next turn, so follow-up prompts land in the same conversation rather than starting cold. It is session continuity, not a persistent process. Who built the Copilot engine? It's the first community-contributed provider in Munder Difflin — PR 101 by @anxkhn, shipped in v0.3.3. The engine registers Copilot as a provider preset alongside Claude Code, Codex, Antigravity, OpenCode, Crush, and pi.dev, and comes with a self-contained registry test asserting the command shape.