GitHub Copilot · repo or home folder

Teach Copilot to spend less.

Skills, custom agents, prompt files and instructions that Copilot picks up from .github/ in a repo, or from ~/.copilot/ in your home folder to apply them to every project. Model and tool names follow the VS Code picker; adjust them to what your editor shows. Find more skills on skills.sh.

Instructions

A lean instruction file

Sent with every request, so keep it to what the model can't infer from the code. About 120 tokens.

This repo: .github/copilot-instructions.md
All projects: Repo only

# Project map
- Next.js App Router. Pages in `app/`, UI in `components/`, logic in `lib/`.
- Data lives in `data/*.json`. Never hand-edit generated files.

# Commands
- `npm run typecheck` and `npm run build` before handing off.

# Rules
- TypeScript strict. Match the surrounding code.
- Reply briefly: what changed, where, how it was verified.

Skill

token-diet skill

Loaded only when relevant. It tells the agent to read less, print less and stop sooner.

This repo: .github/skills/token-diet/SKILL.md
All projects: ~/.copilot/skills/token-diet/SKILL.md

---
name: token-diet
description: Work token-efficiently. Use for routine edits, refactors, and whenever the user asks to keep cost or context small.
---

# Token diet

- Search before reading. Locate the symbol, then read only the lines around it.
- Never re-read a file that is already in context unless it changed.
- Show changed hunks, not whole files.
- Run the narrowest check: one test file or the affected package.
- Trim command output to the lines that matter.
- Ask one clarifying question instead of exploring several guesses.
- Stop when the stated goal is met. List follow-ups instead of doing them.

Custom agent

A cheap read-only scout

Delegate “where is…” and “how does…” questions to a small model and get back references, not file dumps.

This repo: .github/agents/scout.agent.md
All projects: ~/.copilot/agents/scout.agent.md

---
description: Read-only scout that finds code and answers where/how questions.
model: Claude Haiku 5.5 (copilot)
tools: ['search', 'read']
---

You are a scout. Find the files, symbols and lines that answer the question.

- Search first. Read only the lines you need.
- Never edit files or run commands.
- Answer with a short list of path:line references, one sentence each.

Prompt file

Plan first, build later

Run /plan in chat. The plan lands in a file, so a fresh, cheaper session can implement it.

This repo: .github/prompts/plan.prompt.md
All projects: VS Code user profile

---
description: Research a change and write an implementation plan without editing code.
agent: Plan
---

Research how to implement: ${input:task}

- Read only what you need to decide. Prefer search over opening whole files.
- Write the plan to `plan.md`: goal, files to change, steps, how to verify.
- Stop after writing the plan. Do not change source files.