076 GitHub copilot cost optimization - #1237

Previously missed (13) — in code that hasn't changed since the last review.

076-GitHubCopilotCostOptimization/Student/Challenge-02.md:30

• Agent Skills are discovered and loaded on demand when Copilot determines they are relevant; they do not require explicit invocation. This instruction teaches the wrong activation model and may invalidate the context-cost comparison. Describe the skill as relevance-triggered/on-demand instead.
  076-GitHubCopilotCostOptimization/Student/Challenge-02.md:118
• This path-specific instruction guidance contradicts the supported structure already described on line 28. Scoped instructions belong under .github/instructions/ and use applyTo frontmatter; placing /api/.github/ inside the source tree will not create the intended scope.
  076-GitHubCopilotCostOptimization/Student/Challenge-03.md:34
• This tells students to rerun anomalous results immediately after the first-shot rule forbids reruns. That changes the sample count and undermines a consistent comparison. Keep the measurement single-shot here; discuss repeated validation separately from the recorded run.
  076-GitHubCopilotCostOptimization/Coach/Solution-02.md:98
• Copilot does not scope repository instructions by walking nested .github/copilot-instructions.md files. The reference solution correctly uses .github/instructions/*.instructions.md with applyTo frontmatter, so this troubleshooting advice sends coaches toward an unsupported structure.

GitHub Copilot walks up the directory tree looking for `.github/copilot-instructions.md` files. Ensure:
- Directory structure is correct
- File is named exactly `.github/copilot-instructions.md` (not `.github/copilot-instructions-api.md` in the api folder)

076-GitHubCopilotCostOptimization/Coach/Solution-06.md:26

• All five challenge references are shifted: instruction scoping is Challenge 02, model selection is 03, session/tool hygiene is 04, compaction is 05, and spec-first development is 01. The incorrect mapping will make coaches point participants to the wrong prior material.

This issue also appears on line 40 of the same file.

- Global instructions scoped appropriately (Challenge 01)
- Efficient model selection (Challenge 02)
- Clean session hygiene (Challenge 03)
- Proactive compaction (Challenge 04)
- Spec-first approach (Challenge 05)

076-GitHubCopilotCostOptimization/Coach/Solutions/Challenge-02-NYCApp-Solutions/.github/instructions/events.instructions.md:11

• This scoped rule requires location, but neither the student nor coach event fixtures contain that field, and the stated endpoint acceptance criteria require only name/date/price behavior. The completed solution therefore violates its own instructions; align the required fields with the provided schema.

- Ensure each event has name, date, and location

076-GitHubCopilotCostOptimization/Coach/Solutions/Challenge-03-ModelSelection-Solutions/harness.py:116

• The coach README says the harness defaults to n=4, and all published reference measurements use four trials, but the actual default is 50. Running the documented command without -n therefore incurs 12.5× as many API calls and can heavily rate-limit premium models.

    ap.add_argument("-n", type=int, default=50)

076-GitHubCopilotCostOptimization/Coach/Solution-02.md:21

• Skills are selected automatically when their metadata matches the current task, not only when explicitly invoked; @workspace /new is also unrelated to loading the added Agent Skill. This coach explanation would reinforce the same incorrect activation model taught to students.

2. **GitHub Copilot Skills (conditional cost):**
   - Only load when explicitly invoked
   - Example: `@workspace /new` only loads creation templates when called

.devcontainer/devcontainer.json:8

• This newly added default devcontainer is for hack 031 and opens /workspace/031-DevOpsWithGitHub, not the 076 materials introduced by this PR. Because it occupies the default .devcontainer/devcontainer.json location, users can launch an unrelated .NET 6 environment instead of the 076 TypeScript/Python configuration. Remove this file or replace it with the 076 configuration.

  "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",

076-GitHubCopilotCostOptimization/README.md:25

• Challenge 01 explicitly excludes automated tests and frames the exercise as an observation, not proof that SDD reduces token burn. This summary instead promises a deterministic-control result the exercise neither implements nor requires. Align the overview with the actual direct-prompt-versus-spec comparison.

- Challenge 01: **[Spec-Driven Development](Student/Challenge-01.md)**
   - Demonstrate that deterministic controls (tests, specs) reduce trial-and-error token burn

076-GitHubCopilotCostOptimization/Coach/Solution-01.md:1

• This guide does not use Spec Kit: it deliberately uses a single manually created sdd.md with no Spec Kit commands, constitution, plan, or tasks. Calling it “with Spec Kit” contradicts the student exercise and the rest of this coach guide.

# Challenge 01 - Spec-Driven Development with Spec Kit - Coach's Guide

076-GitHubCopilotCostOptimization/Coach/Solution-05.md:15

• These exact context-utilization thresholds are presented as deterministic behavior, yet the guide provides no measurement basis and later requires degradation after 70%. Quality degradation varies by model, task, and context composition, so a participant may run the experiment correctly and still fail the stated criterion. Label these as hypotheses/illustrative ranges and grade the recorded observation rather than a required outcome.

- 0-60% capacity: Quality remains high
- 60-70% capacity: First signs of degradation (inconsistencies)
- 70-85% capacity: Noticeable quality loss, forgotten requirements
- 85-100% capacity: Severe degradation, expensive recovery loops

076-GitHubCopilotCostOptimization/Coach/README.md:105

• These bullets contradict the explicit statement on lines 65–67 that the hack requires no Azure resources. Remove this leftover template content so coaches are not told to prepare nonexistent Azure dependencies.

This issue also appears on line 107 of the same file.

- 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.

076-GitHubCopilotCostOptimization/Student/Challenge-06.md:17

• Student/Resources/Challenge06 contains only data/sales.csv; the task specification and tests promised here are missing. Consequently, teams cannot know the acceptance criteria, run the required tests, or complete the capstone. Add token-golf-task.md and all referenced test/starter files to the resource folder.
  076-GitHubCopilotCostOptimization/Coach/Solution-06.md:44
• The same off-by-one challenge mapping is repeated in the required scorecard, so teams would attribute every optimization technique to the wrong challenge.

  - Which instruction scoping strategy (Challenge 01)
  - Output constraints used (Challenge 02)
  - Tools pruned (Challenge 03)
  - Compaction points (Challenge 04)
  - Spec-first approach (Challenge 05)

076-GitHubCopilotCostOptimization/Coach/Solutions/Challenge-02-NYCApp-Solutions/src/routes/events.ts:19

• This comparator also subtracts Date objects, which TypeScript rejects. Compare their numeric timestamps instead.

    .sort((a, b) => new Date(a.date) - new Date(b.date));

076-GitHubCopilotCostOptimization/Student/Resources/.devcontainer/devcontainer.json:21

• This resource-level configuration also opens a nonexistent Student/Resources/README.md, so no guide appears when the container starts. Point it to an existing resource README.
  .devcontainer/076-GitHubCopilotCostOptimization/devcontainer.json:23
• The configured startup file does not exist: Student/Resources has no README.md. Codespaces will fail to open the intended guide. Point this to an existing resource entry page, such as the CityScout README.

        "076-GitHubCopilotCostOptimization/Student/Resources/README.md"

076-GitHubCopilotCostOptimization/Coach/Solution-06.md:14

• The documented Token Golf task does not exist in Student/Resources/Challenge06, so the coach cannot perform this mandatory pre-work or establish par. Add the complete task/test assets before making this a critical prerequisite.

**You must complete the Token Golf task yourself before the hack:**

1. Implement the coding task specified in `/Student/Resources/Challenge06/token-golf-task.md`
2. Use optimization techniques from Challenges 1-5

076-GitHubCopilotCostOptimization/Student/Resources/Challenge-02-NYCApp/.github/copilot-instructions.md:147

• This stray two-backtick marker is unmatched and renders as unexplained literal content in the instruction file. Remove it.
  076-GitHubCopilotCostOptimization/Coach/README.md:109
• A complete “Suggested Hack Agenda” and “Repository Contents” already appear above; this second section is untouched template guidance with sample days and duplicated headings. Remove the duplicate template block (lines 107–131) before publishing the coach guide.

## 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:_