076 GitHub copilot cost optimization

.devcontainer/076-GitHubCopilotCostOptimization/devcontainer.json

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+{
+  "name": "076-GitHubCopilotCostOptimization",
+  "image": "mcr.microsoft.com/devcontainers/typescript-node:1-22-bookworm",
+  "workspaceFolder": "/workspace/076-GitHubCopilotCostOptimization/Student/Resources",
+  "workspaceMount": "source=${localWorkspaceFolder},target=/workspace,type=bind,consistency=cached",
+  "hostRequirements": {
+    "cpus": 2
+  },
+  "features": {
+    "ghcr.io/devcontainers/features/python:1": { "version": "3.12" }
+  },
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "github.copilot",
+        "github.copilot-chat",
+        "dbaeumer.vscode-eslint",
+        "esbenp.prettier-vscode"
+      ]
+    },
+    "codespaces": {
+      "openFiles": [
+        "076-GitHubCopilotCostOptimization/Student/Resources/README.md"
+      ]
+    }
+  },
+  "postCreateCommand": "curl -LsSf https://astral.sh/uv/install.sh | sh && ~/.local/bin/uv tool install specify-cli --from git+https://github.com/github/spec-kit.git",
+
+  "forwardPorts": [3000],
+  "portsAttributes": {
+    "3000": {
+      "label": "CityScout NYC App",
+      "onAutoForward": "notify"
+    }
+  }
+}

.devcontainer/devcontainer.json

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+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/dotnet
+{
+  "name" : "DevOps with GitHub WTH in Codespaces",
+	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+	"image": "mcr.microsoft.com/devcontainers/dotnet:0-6.0",
+	"workspaceFolder": "/workspace/031-DevOpsWithGitHub",
+	"workspaceMount": "source=${localWorkspaceFolder},target=/workspace,type=bind,consistency=cached",
+	"features": {
+		"ghcr.io/devcontainers/features/azure-cli:1": {
+			"installBicep": true,
+			"version": "latest"
+		}
+	}
+
+	// Use 'forwardPorts' to make a list of ports inside the container available locally.
+	// "forwardPorts": [5000, 5001],
+	// "portsAttributes": {
+	//		"5001": {
+	//			"protocol": "https"
+	//		}
+	// }
+
+	// Use 'postCreateCommand' to run commands after the container is created.
+	// "postCreateCommand": "dotnet restore",
+
+	// Configure tool-specific properties.
+	// "customizations": {},
+
+	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+	// "remoteUser": "root"
+}

.devcontainer/xxx-GitHubCopilotCostOptimization/devcontainer.json

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+{
+  "name": "076-GitHubCopilotCostOptimization",
+  "image": "mcr.microsoft.com/devcontainers/typescript-node:1-22-bookworm",
+  "workspaceFolder": "/workspace/076-GitHubCopilotCostOptimization/Student/Resources",
+  "workspaceMount": "source=${localWorkspaceFolder},target=/workspace,type=bind,consistency=cached",
+  "hostRequirements": {
+    "cpus": 2
+  },
+  "features": {
+    "ghcr.io/devcontainers/features/python:1": { "version": "3.12" }
+  },
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "github.copilot",
+        "github.copilot-chat",
+        "dbaeumer.vscode-eslint",
+        "esbenp.prettier-vscode"
+      ]
+    },
+    "codespaces": {
+      "openFiles": [
+        "076-GitHubCopilotCostOptimization/Student/Resources/README.md"
+      ]
+    }
+  },
+  "postCreateCommand": "curl -LsSf https://astral.sh/uv/install.sh | sh && ~/.local/bin/uv tool install specify-cli --from git+https://github.com/github/spec-kit.git",
+
+  "forwardPorts": [3000],
+  "portsAttributes": {
+    "3000": {
+      "label": "CityScout NYC App",
+      "onAutoForward": "notify"
+    }
+  }
+}

076-GitHubCopilotCostOptimization/.wordlist.txt

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+UBB
+SDD
+completable
+Unoptimized
+mathrm
+tokenization
+backoff
+invalidations
+subtask
+Linters
+applyTo
+CityScout
+runnable
+Monotonicity
+Andressa
+Siqueira
+Nefedova
+discoverable
+checkable
+pickleball
+breakpoint
+differentiator
+selectable
+NYCApp
+geolocation
+unmanaged
+useEffect
+useState
+YYYY
+priceLevel
+bestFor
+walkability

076-GitHubCopilotCostOptimization/Coach/README.md

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+# What The Hack - GitHub Copilot Cost Optimization - Coach Guide
+
+## Introduction
+
+Welcome to the coach's guide for the GitHub Copilot Cost Optimization What The Hack. Here you will find links to specific guidance for coaches for each of the challenges.
+
+This hack teaches teams to maximize code quality while minimizing GitHub Copilot credit spend under usage-based billing (UBB). The focus is on practical engineering techniques: context engineering, model selection, session hygiene, and spec-driven development.
+
+**NOTE:** If you are a Hackathon participant, this is the answer guide. Don't cheat yourself by looking at these during the hack! Go learn something. :)
+
+## Coach's Guides
+
+- Challenge 00: **[Prerequisites & Baseline](./Solution-00.md)**
+   - Set up the hack environment and establish baseline credit spend measurements
+- Challenge 01: **[Spec-Driven Development](./Solution-01.md)**
+   - Leverage deterministic controls as token controls
+- Challenge 02: **[Context Engineering](./Solution-02.md)**
+   - Optimize instruction architecture and attachment precision
+- Challenge 03: **[Model Selection & Output Constraints](./Solution-03.md)**
+   - Compare models and apply output constraints to reduce costs
+- Challenge 04: **[Session Configuration (Tools + Cache)](./Solution-04.md)**
+   - Manage MCP tool sprawl and understand cache invalidation
+- Challenge 05: **[Context Window Management](./Solution-05.md)**
+   - Use /compact proactively to maintain quality and control costs
+- Challenge 06: **[Token Golf Competition](./Solution-06.md)**
+   - Competitive coding challenge optimizing for lowest credit spend
+
+## Coach Prerequisites
+
+This hack has pre-reqs that a coach is responsible for understanding and/or setting up BEFORE hosting an event. Please review the [What The Hack Hosting Guide](https://aka.ms/wthhost) for information on how to host a hack event.
+
+The guide covers the common preparation steps a coach needs to do before any What The Hack event, including how to properly configure Microsoft Teams.
+
+### Student Resources
+
+Before the hack, it is the Coach's responsibility to download and package up the contents of the `/Student/Resources` folder of this hack into a "Resources.zip" file. The coach should then provide a copy of the Resources.zip file to all students at the start of the hack.
+
+The Student/Resources folder should contain:
+
+- **Starter codebase** with intentionally sub-optimal GitHub Copilot configuration:
+  - Bloated `.github/copilot-instructions.md` (~1500 tokens) for Challenge 02
+  - Multiple MCP tools enabled (some unnecessary) for Challenge 04
+  - Sample code with opportunities for spec-first vs. trial-and-error comparison
+- **Baseline coding task** (baseline-task.md) for Challenge 00
+- **Model selection prompts + measurement template** (`Challenge-03-ModelSelection/`) for Challenge 03
+- **Token Golf task specification** for Challenge 06 with acceptance criteria
+
+Always refer students to the [What The Hack website](https://aka.ms/wth) for the student guide: [https://aka.ms/wth](https://aka.ms/wth)
+
+**NOTE:** Students should **not** be given a link to the What The Hack repo before or during a hack. The student guide does **NOT** have any links to the Coach's guide or the What The Hack repo on GitHub.
+
+### Additional Coach Prerequisites
+
+**Coach must complete Challenge 06 (Token Golf) before the hack:**
+
+- Complete the Token Golf coding task yourself to establish "par" score
+- Document your credit spend and techniques used
+- This "par" becomes the benchmark teams compete against
+
+**Prepare measurement tools:**
+
+- Verify token visibility in VS Code Output panel (GitHub Copilot Chat)
+- Test access to GitHub Copilot usage dashboard
+
+## Azure Requirements
+
+This hack does not require Azure resources. All work is done locally with GitHub Copilot in Visual Studio Code.
+
+## Suggested Hack Agenda
+
+This hack can be delivered as a half-day or full-day event:
+
+### Half-Day Format (4 hours)
+- Challenge 00: Prerequisites & Baseline (30 minutes)
+- Challenge 01: Spec-Driven Development (45 minutes)
+- Challenge 02: Context Engineering (45 minutes)
+- Challenge 03: Model Selection & Output Constraints (45 minutes)
+- Challenge 04: Session Configuration (30 minutes)
+- Challenge 06: Token Golf Competition (45 minutes)
+
+### Full-Day Format (6-7 hours)
+- Challenge 00: Prerequisites & Baseline (45 minutes)
+- Challenge 01: Spec-Driven Development (60 minutes)
+- Challenge 02: Context Engineering (60 minutes)
+- Break (15 minutes)
+- Challenge 03: Model Selection & Output Constraints (60 minutes)
+- Challenge 04: Session Configuration (45 minutes)
+- Challenge 05: Context Window Management (45 minutes)
+- Break (15 minutes)
+- Challenge 06: Token Golf Competition (60 minutes)
+- Debrief & Winning Strategies (30 minutes)
+
+## Repository Contents
+
+- `./Coach`
+  - Coach's Guide and related files
+- `./Coach/Solutions`
+  - Solution files with example measurements and techniques for each challenge
+- `./Student`
+  - Student's Challenge Guide
+- `./Student/Resources`
+  - Starter codebase, baseline task, Token Golf specification (Must be packaged up by the coach and provided to students at start of event)
+
+- Azure resources that will be consumed by a student implementing the hack's challenges
+- Azure permissions required by a student to complete the hack's challenges.
+
+## Suggested Hack Agenda (Optional)
+
+_This section is optional. You may wish to provide an estimate of how long each challenge should take for an average squad of students to complete and/or a proposal of how many challenges a coach should structure each session for a multi-session hack event. For example:_
+
+- Sample Day 1
+  - Challenge 1 (1 hour)
+  - Challenge 2 (30 mins)
+  - Challenge 3 (2 hours)
+- Sample Day 2
+  - Challenge 4 (45 mins)
+  - Challenge 5 (1 hour)
+  - Challenge 6 (45 mins)
+
+## Repository Contents
+
+_The default files & folders are listed below. You may add to this if you want to specify what is in additional sub-folders you may add._
+
+- `./Coach`
+  - Coach's Guide and related files
+- `./Coach/Solutions`
+  - Solution files with completed example answers to a challenge
+- `./Student`
+  - Student's Challenge Guide
+- `./Student/Resources`
+  - Resource files, sample code, scripts, etc meant to be provided to students. (Must be packaged up by the coach and provided to students at start of event)

076-GitHubCopilotCostOptimization/Coach/Solution-00.md

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+# Challenge 00 - Prerequisites & Baseline - Coach's Guide 
+
+**[Home](./README.md)** - [Next Solution >](./Solution-01.md)
+
+## Notes & Guidance
+
+This challenge establishes the measurement baseline that all subsequent challenges compare against. Students must be able to track credit consumption accurately before they can optimize.
+
+### Key Concepts to Explain
+
+**Usage-Based Billing (UBB) Fundamentals:**
+- Credit cost = (input tokens × input rate) + (output tokens × output rate)
+- Different models have different rates (Sonnet/GPT-4 class vs. Haiku class can be 10x difference)
+- VS Code Output panel shows token breakdowns per interaction
+- GitHub Copilot usage dashboard shows cumulative spend
+
+**Baseline Purpose:**
+- Establishes "before" measurement for all optimization techniques
+- Students should use their natural workflow—no optimization yet
+- Document approach (inline completions, chat frequency, workspace references used)
+- This baseline will likely be inefficient—that's intentional
+
+### Common Blockers
+
+**UBB Not Enabled:**
+- Some organizations may still be on seat-based billing
+- Students need admin access or must coordinate with billing admin
+- Workaround: Coach can provide sample baseline data if UBB isn't available
+
+**Token Visibility Issues:**
+- VS Code Output panel must be configured to show GitHub Copilot Chat logs
+- Some students may not see token counts if using older Copilot extension version
+- Solution: Update GitHub Copilot extension to latest version
+
+**Baseline Task Selection:**
+- Task should be non-trivial (10-20 minutes of development)
+- Task should be completable in multiple ways (leaves room for optimization)
+- Suggested baseline tasks:
+  - Implement a REST API endpoint with validation and error handling
+  - Add authentication middleware to an existing service
+  - Refactor a module to use dependency injection
+
+### Expected Time
+
+45 minutes total:
+- 15 minutes: Environment setup and UBB verification
+- 20 minutes: Complete baseline coding task
+- 10 minutes: Document measurements and approach
+
+### Success Criteria Validation
+
+Students should demonstrate:
+- Screenshot or screen share of VS Code Output panel showing token counts
+- Screenshot of GitHub Copilot usage dashboard showing current credit balance
+- Completed baseline task code (doesn't need to be perfect)
+- Written documentation: total credits consumed, features used, approach taken
+
+### Hints to Share
+
+- Don't optimize yet! Use your natural workflow
+- Document everything—this is your "before" picture
+- If credits seem surprisingly high, that's normal and expected
+- Track not just total credits, but which interactions cost the most
+- Note: inline completions are typically much cheaper per-interaction than chat/edits
+
+### Reference Measurements
+
+Typical baseline measurements for a 15-20 minute coding task:
+- Unoptimized: 50-80 credits (using GPT-4 class model, verbose chat, broad references)
+- Expected after optimization: 10-20 credits (targeted instructions, efficient model, pinned attachments)
+
+### Additional Resources for Coach
+
+- Ensure Resources.zip contains `baseline-task.md` with clear requirements
+- Consider providing a reference completion for teams that get stuck
+- Have sample token breakdowns ready to share if students can't see theirs