docs(F001): comprehensive implementation plan for security fixes

[jschulte]

Generated complete implementation planning artifacts:

• impl-plan.md: Main implementation plan with technical context
• research.md: Resolved all unknowns and best practices
• data-model.md: Security validation model and patterns
• contracts/README.md: Internal contract documentation
• quickstart.md: Developer implementation guide (400+ lines)
• agent-context.md: Technology patterns and anti-patterns

Planning Summary:

• Fixes: CWE-22 (path traversal), CWE-400 (DoS), CWE-502 (deserialization)
• CVSS: 7.5 HIGH → 0 (after implementation)
• Effort: 7-9 hours estimated
• Dependencies: Zero new dependencies
• Tests: 12+ new security tests planned
• Coverage: Resources 0% → 80%+

Constitution Compliance:
✅ Security First - Comprehensive validation at all entry points
✅ Zero Technical Debt - All clarifications resolved
✅ Minimal Dependencies - Uses existing utilities only
✅ Comprehensive Testing - 100% security module coverage maintained

Artifacts Status:
✅ Phase 0: Research complete (all unknowns resolved)
✅ Phase 1: Design complete (all artifacts generated)
✅ Constitution Check: APPROVED for implementation
⏳ Phase 2: Ready for implementation

Branch: claude/plan-security-fixes-01SpAKwWbaX7Pr2wm1ti1j25
Feature: F001-security-fixes

[Copilot]

Pull Request Overview

This PR adds comprehensive planning and implementation artifacts for security fixes addressing critical vulnerabilities (CVSS 7.5 HIGH) in the StackShift MCP server. The changes implement path traversal prevention (CWE-22), resource exhaustion protection (CWE-400), and prototype pollution mitigation (CWE-502) in resource handlers and the skill loader.

Key changes:

• Security validation added to all resource handlers (state, progress, route)
• Input validation and security checks added to skill loader
• New comprehensive security test suites for resources and skill loader
• Extensive planning documentation including research, implementation plans, quickstart guide, and data models

Reviewed Changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tasks.md	Comprehensive task breakdown with 62 tasks across 8 phases for implementation
spec.md	Updated success criteria from unchecked to completed with test results
research.md	510-line research document resolving 5 key unknowns and documenting security best practices
quickstart.md	835-line developer implementation guide with step-by-step instructions
impl-plan.md	614-line technical implementation plan with constitution compliance checks
data-model.md	616-line security validation model and patterns documentation
contracts/README.md	271-line contract documentation confirming no external API changes
agent-context.md	340-line technology patterns and anti-patterns for future development
skill-loader.ts	Added input validation (skill name, HOME env) and switched to safe file operations
skill-loader.test.ts	Added HOME environment variable setup for security validation
skill-loader.security.test.ts	New 71-line test suite with 7 security validation tests
resources/index.ts	Added security validation to 3 resource handlers using createDefaultValidator and readJsonSafe
resources/security.test.ts	New 148-line comprehensive security test suite with 6 test cases
index.ts	Minor type assertion fix in cruise control handler

Comments suppressed due to low confidence (2)

production-readiness-specs/F001-security-fixes/data-model.md:1

• The approach of using delete to remove __proto__ may not work reliably across all JavaScript engines. A more robust approach is to use Object.create(null) to copy properties without prototype, or use a library like json-parse-safe. Additionally, you should delete these properties recursively for nested objects, not just at the root level.

# Data Model: F001-security-fixes

production-readiness-specs/F001-security-fixes/impl-plan.md:1

• The readJsonSafe implementation only removes dangerous properties at the root level. Nested objects can still have __proto__, constructor, or prototype properties that could lead to prototype pollution. Consider implementing recursive sanitization or using a more robust solution like creating a clean object with Object.create(null) and copying safe properties.

# Implementation Plan: F001-security-fixes

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[Copilot]

The type assertion change still uses any, which bypasses type checking. The original (args as any) || {} was problematic, but args || {} as CruiseControlArgs would be better - asserting the specific type after applying the default. This would maintain type safety while still providing the fallback.

[Copilot]

[nitpick] The 'Current state (vulnerable)' code example shows const state = await fs.readFile(stateFile, 'utf-8'); but this returns a string, not the name state. In the actual vulnerable code (shown in resources/index.ts), the variable stores the raw string content. Consider renaming to stateData or stateJson for clarity in the example to avoid confusion.

Suggested change

	const state = await fs.readFile(stateFile, 'utf-8');
	return {
	contents: [
	{
	uri: 'stackshift://state',
	mimeType: 'application/json',
	text: state,
	const stateData = await fs.readFile(stateFile, 'utf-8');
	return {
	contents: [
	{
	uri: 'stackshift://state',
	mimeType: 'application/json',
	text: stateData,

[Copilot]

[nitpick] The validation of process.env.HOME occurs every time loadSkillFile is called, even though HOME rarely changes during execution. Consider validating and caching the validated home path at module initialization to avoid repeated validation overhead and improve performance.

[Copilot]

[nitpick] The example shows creating 11MB of 'A' characters, but when wrapped in JSON the total file size exceeds 11MB. While the test still works (file is > 10MB), the comment on line 465 says '11MB' which might confuse developers. Consider clarifying that the JSON structure adds overhead, or adjust to create exactly 11MB of total file content.

Suggested change

	// Create large file (11MB)
	// Create large file (>11MB including JSON overhead)