Spec-Driven-Development copilot-instructions.md

Project instructions for GitHub Copilot, an AI coding assistant, in a task-board project that uses spec-driven development. Spec-driven development means requirements, system design, and the ordered task list guide the implementation.

In plain words
What is it for?
Use them when Copilot works on the engineering task board: read the project context and specifications, implement only approved work, verify acceptance criteria, update completed tasks, and report any divergence.
Why use it?
They keep coding work aligned with the project's written requirements and design. They also require checks before and after each task, and call for questions when the instructions are unclear.

Instructions file for GitHub Copilot

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add instructions/fredantb/spec-driven-development/copilot-instructions
Clone the repo
git clone --depth 1 https://github.com/FredAntB/Spec-Driven-Development

Made for: GitHub Copilot.

Per session 437 This file is loaded in full into every session.
When invoked 437 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00437 $0.00437
Opus 5 $0.00218 $0.00218
Sonnet 5 $0.00087 $0.00087
Haiku 4.5 $0.00044 $0.00044

Measured 2d ago against content hash d3202d1f2c78, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Spec-Driven-Development copilot-instructions.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

phase2c/flow_c/.github/copilot-instructions.md · 47 lines

What it actually says

GitHub Copilot Instructions

Project: Engineering Task Board — v1.0

═══════════════════════════════════════════════════════════ SPEC DRIVEN DEVELOPMENT — PROJECT CONSTITUTION Project: Engineering Task Board Version: v1.0

This project uses Spec Driven Development. All work is governed by three source-of-truth files:

requirements.md — What the system must do design.md — How the system is structured tasks.md — The ordered implementation plan

MANDATORY BEFORE ANY ACTION: 0. If CONTEXT.md exists, read it first — it has session state

  1. Read requirements.md in full
  2. Read design.md in full
  3. Read tasks.md — find the next incomplete [ ] task

HARD CONSTRAINTS:

  • Implement ONLY what is in requirements.md
  • Match EXACTLY the data model in design.md
  • Create ONLY files listed or implied by design.md
  • Never mark a task [x] without verifying its acceptance criterion
  • If a requirement is ambiguous: ASK, do not guess
  • If scope creep is detected: FLAG it, do not implement

AFTER COMPLETING A TASK:

  1. Run the verification step listed in tasks.md
  2. Mark the task [x] in tasks.md
  3. Report what was done and which REQ/NFR it satisfies

DIVERGENCE PROTOCOL: If implementation must deviate from design.md: 1. Stop immediately 2. Describe the conflict to the user 3. Wait for explicit approval to update design.md 4. Update design.md FIRST, then implement ═══════════════════════════════════════════════════════════

Copilot-Specific

  • These instructions apply to Copilot Chat and inline completions.
  • When generating code in a file, check whether that file is referenced in design.md before adding new exports or APIs.
  • Do not propose dependencies that are absent from package.json / pyproject.toml without flagging the addition.
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 47 lines · 437 tokens per session scan A d3202d1f2c78

Subscribe to this mod's changes

Spec-Driven-Development copilot-instructions.md is an instructions file published in the GitHub repository FredAntB/Spec-Driven-Development (152 stars, last pushed 3mo ago), licensed MIT. It adds 437 tokens to every session, about $0.0022 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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