Index Project Requirements Document (PRD)

September 14, 2026 · View on GitHub

Version: 1.8.1 (Supersedes 1.4.2; incorporates ToolTier system, dispatcher flat-param assembly, schema completeness, constitution Q-7/Q-8)
Status: Binding - Authoritative Project Governance Document
Owner: Project Maintainers & Governance Working Group
Last Updated: February 24, 2026
Next Review: overdue — the May 24 2026 date passed unreviewed, and the footer of this same document still says "November 28, 2025" (#591). Two conflicting review dates, both in the past, is the same as none.

🎯 Executive Summary

The Index is a deterministic instruction indexing platform designed for AI assistant governance and developer tooling. This PRD establishes binding requirements for project structure, architectural patterns, MCP SDK compliance, JSON-RPC protocol adherence, application standards, reliability objectives, comprehensive testing mandates, and security/PII protection protocols.

Business Value Proposition:

Governance Assurance: Deterministic instruction management with tamper detection and audit trails
Enterprise Compliance: PII protection, security controls, and regulatory compliance readiness
Operational Excellence: 99.9% availability with <120ms P95 response times at enterprise scale
Risk Mitigation: Comprehensive testing, security scanning, and change management controls
Developer Productivity: Standards-based MCP integration with comprehensive tooling and APIs

This document serves as the single source of truth for all project processes, technical decisions, and quality standards. All development activities must adhere to the specifications outlined herein.

🔄 Since 1.3.1 → 1.4.2 Delta (Ratified Enhancements)

Area	Change	Rationale	Status
Instruction Schema	Upgraded to schema v3 with `primaryCategory` invariant	Deterministic category referencing + forward compatibility	Ratified
Governance Versioning	Strict semver validation on create & update (`invalid_semver` rejection)	Prevent malformed version lineage	Ratified
Governance Mutations	Metadata-only overwrite hydration (omit body on overwrite)	Ergonomic governance edits; reduces payload redundancy	Ratified
ChangeLog Integrity	Silent normalization & repair on malformed changeLog arrays	Stability; avoids editor-induced failures	Ratified
Overwrite Telemetry	Correct `overwritten:true` for metadata-only higher-version updates	Accurate mutation metrics	Ratified
Feedback System	Full 6-tool feedback lifecycle (submit/list/get/update/stats/health)	Operational quality & triage	Ratified
Visibility Reliability	Opportunistic in‑memory materialization (no reload) + skip path self-healing	Eliminates add→get race & reduces disk churn	Ratified
Manifest Observability	Unified manifest write helper + counters (`manifest:write*`)	Deterministic structural drift diagnostics	Ratified
Manifest Disable Mode	`INDEX_SERVER_MANIFEST_WRITE=0` runtime flag	Safe read‑only diagnostics	Ratified
Fastload Placeholder	Reserved `INDEX_SERVER_MANIFEST_FASTLOAD` env	Forward perf optimization staging	Ratified
Hash Governance	Justified hash drift (schema normalization) via `governance/ALLOW_HASH_CHANGE`	Transparent integrity exceptions	Ratified
Baseline Protection	Guard scripts & sentinel markers enforcing minimal invariant set	Prevent uncontrolled test sprawl	Ratified

All above changes are binding; earlier “pending ratification” addendum items have been merged into the authoritative baseline. Future provisional items will again appear under an Addendum section.

✳️ Addendum (Pending Ratification → 1.2.0) – Newly Formalized Requirements

These requirements are already implemented in code/tests but lacked explicit PRD coverage. Until ratification they are treated as binding interim policy.

The "→ 1.2.0" in this heading is dead (#591). The package shipped 1.2.0 and many versions beyond it without this addendum ever being ratified, so the version it names cannot be the ratification target. The requirements below are in force as interim policy; ratification needs a current version target chosen when it actually happens.

1. Feedback / Emit System (No Change This Cycle)

Tools: feedback_submit only; dashboard feedback CRUD via operator HTTP API (not MCP).

Functional Requirements

ID	Requirement	Rationale	Verification
FB1	Enumerated types: issue, bug-report, feature-request, security, documentation, performance, usability, other	Normalized taxonomy	Schema enum + submit tests
FB2	Severities: low, medium, high, critical	Prioritization	Schema enum + stats aggregation
FB3	Status workflow new→acknowledged→in-progress→resolved→closed	Lifecycle traceability	update tests enforce transitions
FB4	Atomic durable persistence with rotation on max entries	Corruption prevention	File write uses temp + rename strategy
FB5	Filterable list (type, severity, status, date range, tags, limit/offset)	Operational triage	list tests exercising filters
FB6	Statistics endpoint provides byType/bySeverity/byStatus + recentActivity	Reporting & dashboard	stats test
FB7	Health endpoint returns storage counts & config (maxEntries, dir)	Monitoring	health test
FB8	Security & critical entries produce elevated log channel event	Audit & alerting	log assertion (future automated)
FB9	Page size hard limit 200 (reject >200)	Resource safety	boundary test
FB10	Length limits: title≤200, description≤2000, adminNotes≤1000	Abuse mitigation	validation tests (schema-aligned)

Non-Functional

NFR-FB-1: Median local submit latency <50ms.
NFR-FB-2: No data loss on mid-write crash (verified by atomic pattern review).

2. SDK Test Client CRUD & Governance Baseline (Updated v1.7.0+)

Baseline Test Set (MUST stay green, no skips):

createReadSmoke.spec.ts
governanceHashIntegrity.spec.ts (6 scenarios: create-stability, body-update-change, metadata-stability, multi-create consistency, overwrite-or-skip, drift lifecycle)
dispatcherAddFlatParams.spec.ts (11 tests: flat-param add, nested entry compat, import, governanceUpdate, groom, remove, schema contracts)

Note: The portable client was removed in v1.7.0. All integration tests now use mcpTestClient.ts (SDK-based). See CHANGELOG [1.7.0] for migration details.

Expanding beyond this nucleus (stress, fuzz, multi-process contention) requires formal CHANGE REQUEST with stability impact analysis.

3. Governance Hash Integrity Policy (Stable)

The standalone governance hash test plan file has been deprecated (single-plan consolidation). The following inline protocol is now binding for any governance hash projection change:

Step	Requirement	Details
1	Change Proposal	Pull request MUST include rationale, field diff (added/removed), and expected stability impact (hash churn %)
2	Stability Classification	Label change as: PATCH (non-breaking ordering tweak), MINOR (adds projected field — hash changes for all entries), MAJOR (removes/renames field or semantic re-derivation)
3	Test Adjustment	Update existing governance hash tests with new expected projection & add regression ensuring old hash mismatches (documented)
4	Migration Safety	If field added requires enrichment pass, note idempotency & fallback behavior
5	Rollout Note	CHANGELOG entry summarizing impact + upgrade note for downstream caches
6	Approval	At least one governance maintainer & one reviewer sign-off (recorded in PR)

Drift Lifecycle: Acceptable transient sequence remains ≤3 states (stable → modification proposal → ratified). More than 3 successive rapid hash changes within 14 days requires formal stability review.

Status Field Scope: Current instruction.schema.json status enum = draft | review | approved | deprecated. The governanceUpdate tool previously exposed superseded — this state is deprecated for now; replacement relationships should use deprecated + deprecatedBy field. Future addition of superseded requires this section + schema update.

4. Declaration & Skip Guard Enforcement (Stable)

ID	Requirement	Enforcement
DG1	Single consolidated SDK test client declaration file (allowlist)	`guard-declarations.mjs` (build:verify)
DG2	Zero unintentional TS7016 errors; any `@ts-expect-error` must include portability comment	Typecheck + code review
DG3	No `describe.skip` / `it.skip` unless line tagged `SKIP_OK` + justification	`guard:skips` pretest stage
DG4	New `.d.ts` additions require explicit guard allowlist update	Guard failure -> review

5. Deployment Wipe Modes (Stable)

scripts/deploy-local.ps1 MUST preserve these semantics:

Flags	Behavior	Use Case	Acceptance
`-Overwrite`	Backup then preserve existing instructions	Rolling upgrade	Files unchanged except dist/version
`-Overwrite -EmptyIndex`	Backup then remove all instructions	Clean forensic reset	Index empty post-deploy
`-Overwrite -ForceSeed`	Backup then replace with seed set	Developer bootstrap	Seed set present exactly
`-Overwrite -EmptyIndex -ForceSeed`	Empty then seed	Reset with known corpus	Only seed entries exist
(default)	Install prod-only deps	Always-on for reliable deploys	node_modules excludes dev deps; dependencies always installed via lock file

Backups stored under backups/instructions-<timestamp>; non-fatal count warnings allowed; persistent failure requires issue filing within 1 business day.

6. Documentation Canonicalization (Updated)

ID	Rule	Action
DOC1	`project_prd.md` is canonical PRD	Version bump on each ratified addendum
DOC2	~~Legacy `PRD.md` & `project_prd.md` remain stubs only~~	Void (#591). This rule contradicted DOC1 directly above it — the same file cannot be both the canonical PRD and a stub. `PRD.md` no longer exists anywhere in the repo. DOC1 governs.
DOC3	README must link feedback system & governance hash plan	Verified during release checklist
DOC4	`content_guidance.md` must state NOT to embed MCP tool Indexs/schemas in instructions (protocol discovery only)	Explicit bullet retained

7. Schema‑Aided Add Failure Contract (Ratified)

ID	Requirement	Rationale	Verification
AF1	`index_add` MUST include `schemaRef` & `inputSchema` when returning early structural errors (`missing entry`, `missing id`, `missing required fields`)	Zero round‑trip remediation; improves client UX	Automated test asserting presence on shape errors
AF2	Inline `inputSchema` MUST be authoritative subset of canonical tool schema (no divergence)	Prevent stale or conflicting schema copies	Compare hash of inline schema subset vs canonical registry schema during test
AF3	Non-structural governance/semantic failures (e.g. owner/category policy) MUST NOT echo full schema	Avoid noisy payloads; clarity of failure class	Negative test verifying absence
AF4	`schemaRef` value stable logical key `index_add#input`	Enables client cache keying	Test asserts constant string
AF5	Feature considered additive; clients silently ignoring fields remain functional	Backward compatibility guarantee	Document review + absence of breaking changes in tests

All AF requirements are now binding; failure to include schemaRef or authoritative subset on structural add failures constitutes a regression (P0 severity).

8. Manifest & Materialization Requirements (New 1.4.2)

ID	Requirement	Rationale	Verification
MF1	Successful mutations MUST invoke unified manifest helper once	Centralized error handling & metrics	Mutation tests assert counter increments
MF2	Manifest writes MUST be atomic (temp + rename)	Crash safety	File inspection during simulated crash harness
MF3	`manifest:writeFailed` increments on error; process continues	Non-fatal resilience	Induced IO error test
MF4	Opportunistic writeEntry MUST surface new id immediately w/out reload	Eliminates race	IndexContext usage/materialization test
MF5	Touching `.index-version` MUST sync in-memory token/mtime	Prevent spurious reload loop	Unit test asserts no immediate reload trace
MF6	`INDEX_SERVER_MANIFEST_WRITE=0` MUST suppress writes silently	Diagnostic read-only mode	Disabled mode test (no file mtime change)
MF7	Fastload flag reserved; enabling early MUST fallback gracefully	Forward compatibility	Env flag placeholder test

Non-Functional:

NFR-MF-1: Opportunistic add path P95 < 5ms at 5k entries (excludes file system write of entry itself).
NFR-MF-2: Manifest generation P95 < 40ms at 10k entries.

🏗️ Project Architecture & Structure

High-Level System Architecture

---
config:
    layout: elk
---
graph TB
    subgraph "Client Layer"
        VS[VS Code MCP Client]
        API[API Consumers]
        CLI[CLI Tools]
    end
    
    subgraph "Protocol Layer"
        JSONRPC[JSON-RPC 2.0 Transport]
        MCP[MCP SDK v1.0+]
        STDIO[STDIO Communication]
    end
    
    subgraph "Application Layer"
        DISP[Instructions Dispatcher]
        TOOLS[Tool Registry]
        AUTH[Authentication/Authorization]
        VALID[Input Validation]
    end
    
    subgraph "Business Logic Layer"
        CAT[Index Context]
        GOV[Governance Engine]
        INT[Integrity Verification]
        USAGE[Usage Tracking]
        GATES[Policy Gates]
    end
    
    subgraph "Data Layer"
        FILES[Instruction Files]
        SNAP[Usage Snapshots]
        CACHE[In-Memory Cache]
        SCHEMA[Schema Migration]
    end
    
    subgraph "Infrastructure Layer"
        LOG[Structured Logging]
        METRICS[Performance Metrics]
        HEALTH[Health Monitoring]
        SEC[Security Guards]
    end
    
    VS --> JSONRPC
    API --> JSONRPC
    CLI --> JSONRPC
    
    JSONRPC --> MCP
    MCP --> STDIO
    
    STDIO --> DISP
    DISP --> TOOLS
    TOOLS --> AUTH
    AUTH --> VALID
    
    VALID --> CAT
    CAT --> GOV
    CAT --> INT
    CAT --> USAGE
    CAT --> GATES
    
    CAT --> FILES
    USAGE --> SNAP
    CAT --> CACHE
    FILES --> SCHEMA
    
    LOG --> METRICS
    METRICS --> HEALTH
    HEALTH --> SEC
    
    classDef client fill:#e1f5fe
    classDef protocol fill:#f3e5f5
    classDef app fill:#e8f5e8
    classDef business fill:#fff3e0
    classDef data fill:#fce4ec
    classDef infra fill:#f1f8e9
    
    class VS,API,CLI client
    class JSONRPC,MCP,STDIO protocol
    class DISP,TOOLS,AUTH,VALID app
    class CAT,GOV,INT,USAGE,GATES business
    class FILES,SNAP,CACHE,SCHEMA data
    class LOG,METRICS,HEALTH,SEC infra

Data Flow Architecture

---
config:
    layout: elk
---
sequenceDiagram
    participant Client as MCP Client
    participant Transport as JSON-RPC Transport
    participant Dispatcher as Instructions Dispatcher
    participant Index as Index Context
    participant Governance as Governance Engine
    participant Files as File System
    
    Client->>Transport: initialize(protocolVersion)
    Transport->>Client: server/ready + capabilities
    
    Client->>Transport: tools/call(index_dispatch)
    Transport->>Dispatcher: route(action, params)
    
    alt Read Operations
        Dispatcher->>Index: ensureLoaded()
        Index->>Files: readInstructions()
        Files-->>Index: instruction data
        Index-->>Dispatcher: cached results
        Dispatcher-->>Transport: success response
    else Write Operations (Gated)
        Dispatcher->>Dispatcher: checkMutationGate()
        Dispatcher->>Governance: validateGovernance()
        Governance-->>Dispatcher: validation result
        Dispatcher->>Index: performMutation()
        Index->>Files: writeChanges()
        Files-->>Index: write confirmation
        Index-->>Dispatcher: mutation result
        Dispatcher-->>Transport: success response
    end
    
    Transport-->>Client: JSON-RPC result

Enterprise Application Structure

Directory Structure (Mandatory)

index-server/
├── src/                          # Source code (TypeScript)
│   ├── server/                   # Server bootstrap & configuration
│   │   ├── index.ts             # Main entry point
│   │   ├── sdkServer.ts         # MCP SDK integration
│   │   └── transport.ts         # JSON-RPC transport layer
│   ├── services/                # Business logic services
│   │   ├── IndexContext.ts    # Index management
│   │   ├── toolHandlers.ts      # Tool implementations
│   │   ├── governanceService.ts # Governance engine
│   │   └── validationService.ts # Input validation
│   ├── tests/                   # Comprehensive test suites
│   │   ├── integration/         # Integration tests
│   │   ├── unit/               # Unit tests
│   │   └── handshake/          # JSON-RPC handshake tests
│   └── types/                   # TypeScript type definitions
├── docs/                        # Documentation (binding)
│   ├── project_prd.md           # This document (authoritative)
│   ├── architecture.md          # Technical architecture
│   ├── tools.md                 # Complete API documentation
│   ├── mcp_configuration.md     # Configuration and setup guide
│   ├── prompt_optimization.md   # Prompt handling best practices
│   └── SECURITY.md              # Security specifications
├── schemas/                     # JSON Schema definitions
├── instructions/                # instruction index storage
├── scripts/                     # Build & deployment scripts
└── dist/                        # Compiled output (CommonJS)

🏢 Enterprise Standards & Compliance

MCP SDK Schema Adherence (MANDATORY)

Protocol Compliance
- MUST implement MCP SDK v1.0+ specifications exactly
- MUST support JSON-RPC 2.0 without deviations
- MUST provide proper initialize/ready handshake sequence
- MUST implement tools/list and tools/call methods
- MUST support proper error handling with standard codes
Schema Validation
- ALL input parameters MUST be validated against JSON schemas
- ALL responses MUST conform to MCP response envelope format
- Tool schemas MUST be registered and discoverable
- Version compatibility MUST be enforced
Transport Requirements
- STDIO transport MUST be primary interface
- JSON-RPC framing MUST be exact (one JSON object per line)
- Error responses MUST include proper error codes and messages
- Handshake ordering MUST be deterministic and tested

JSON-RPC Protocol Requirements (BINDING)

stateDiagram-v2
    [*] --> Connecting
    Connecting --> Initializing: client connects
    Initializing --> Ready: initialize success
    Ready --> Processing: tool calls
    Processing --> Ready: responses
    Ready --> Shutdown: shutdown request
    Shutdown --> [*]: exit
    
    Initializing --> Error: initialize fails
    Processing --> Error: tool error
    Error --> Ready: recoverable
    Error --> [*]: fatal

Message Format Standards

// Request (MANDATORY format)
interface JsonRpcRequest {
  jsonrpc: "2.0";           // MUST be exactly "2.0"
  id: string | number;      // MUST be present for requests
  method: string;           // MUST match registered tool
  params?: Record<string, unknown>; // MUST validate against schema
}

// Response (MANDATORY format)  
interface JsonRpcResponse {
  jsonrpc: "2.0";
  id: string | number;      // MUST match request id
  result?: unknown;         // Success response
  error?: JsonRpcError;     // Error response (mutually exclusive)
}

Error Handling Requirements
- Parse Error (-32700): Invalid JSON
- Invalid Request (-32600): Malformed request object
- Method Not Found (-32601): Unknown tool/method
- Invalid Params (-32602): Parameter validation failure
- Internal Error (-32603): Server-side processing error
- Custom errors (application-specific codes)

Reliability & Performance Standards (NON-NEGOTIABLE)

Service Level Objectives (SLOs)

Metric	Target	Measurement
Availability	99.9%	Health check success rate
P95 Response Time	<120ms	Tool call latency
P99 Response Time	<500ms	Tool call latency
Memory Usage	<512MB	Peak RSS during operation
Error Rate	<0.1%	Failed requests / total requests
Handshake Success	100%	Initialize/ready sequence

Performance Requirements

---
config:
    layout: elk
---
graph LR
    subgraph "Response Time Targets"
        A[tools/list<br/>≤50ms P95] 
        B[index_dispatch<br/>≤120ms P95]
        C[governance/hash<br/>≤200ms P95]
        D[integrity_verify<br/>≤1000ms P95]
    end
    
    subgraph "Throughput Targets"
        E[100 req/sec<br/>sustained]
        F[1000 req/sec<br/>burst]
    end
    
    subgraph "Resource Limits"
        G[Memory<br/>≤512MB RSS]
        H[CPU<br/>≤80% avg]
        I[Disk I/O<br/>≤100MB/s]
    end

🧪 Testing Requirements (BINDING)

Comprehensive Test Coverage Mandate

MINIMUM COVERAGE REQUIREMENTS:

Overall Code Coverage: ≥95%
Line Coverage: ≥98%
Branch Coverage: ≥95%
Function Coverage: 100%

JSON-RPC Handshake Testing (CRITICAL)

---
config:
    layout: elk
---
graph TD
    A[Start Test] --> B[Spawn Server Process]
    B --> C[Send Initialize Request]
    C --> D{Initialize Response?}
    D -->|No| E[FAIL: No Response]
    D -->|Yes| F[Validate Response Schema]
    F --> G{Schema Valid?}
    G -->|No| H[FAIL: Invalid Schema]
    G -->|Yes| I[Wait for server/ready]
    I --> J{Ready Received?}
    J -->|No| K[FAIL: No Ready]
    J -->|Yes| L[Validate Ready Ordering]
    L --> M{Proper Order?}
    M -->|No| N[FAIL: Wrong Order]
    M -->|Yes| O[Send tools/list]
    O --> P[Validate Tools Response]
    P --> Q[PASS: Handshake OK]
    
    E --> R[End Test]
    H --> R
    K --> R
    N --> R
    Q --> R

Mandatory Handshake Test Categories

Protocol Compliance Tests
- Initialize request/response validation
- Server ready notification timing
- Tools list schema compliance
- Error response format validation
Ordering & Timing Tests
- Initialize → ready → tools sequence
- Concurrent request handling
- Request ID correlation
- Timeout handling
Error Condition Tests
- Invalid JSON handling
- Unknown method responses
- Parameter validation errors
- Server error recovery
Performance Tests
- Handshake latency measurement
- Concurrent client handling
- Memory leak detection
- Resource cleanup verification

Index Server Schema Testing (MANDATORY)

Schema Evolution Requirements:

// Schema validation test requirements
describe('Index Server Schema Compliance', () => {
  it('MUST validate instruction schema v2', () => {
    const instruction = loadTestInstruction();
    expect(validateInstructionSchema(instruction)).toBe(true);
  });
  
  it('MUST handle schema migration idempotently', () => {
    const v1Instruction = loadV1Instruction();
    const migrated = migrateToV2(v1Instruction);
    const reMigrated = migrateToV2(migrated);
    expect(migrated).toEqual(reMigrated);
  });
  
  it('MUST preserve governance hash stability', () => {
    const instruction = loadTestInstruction();
    const hash1 = computeGovernanceHash(instruction);
    // Perform schema migration
    const migrated = migrateToV2(instruction);
    const hash2 = computeGovernanceHash(migrated);
    expect(hash1).toBe(hash2);
  });

  it('MUST maintain backward compatibility', () => {
    const v1Schema = loadSchemaVersion(1);
    const v2Schema = loadSchemaVersion(2);
    expect(isBackwardCompatible(v1Schema, v2Schema)).toBe(true);
  });
});

Schema Documentation & Maintenance (BINDING)

Schema Governance Requirements:

Documentation Standards
- ALL schema changes MUST be documented in the active schema evolution section of the PRD (deprecated: SCHEMA-V2-PLAN.md)
- Schema evolution MUST include migration guides
- Breaking changes MUST have deprecation notices (minimum 1 minor version)
- All fields MUST have comprehensive descriptions and validation rules
Version Control
- Schema versions MUST follow semantic versioning
- Schema files MUST be stored in /schemas directory
- Migration logic MUST be tested with >95% coverage
- Governance hash stability MUST be verified across schema changes
Review Process
- Schema changes MUST undergo technical committee review
- Database migration scripts MUST be peer-reviewed
- Performance impact MUST be assessed for schema modifications
- Rollback procedures MUST be documented and tested
Compliance Verification
- Schema validation MUST occur on every data operation
- Migration idempotence MUST be verified with automated tests
- Governance hash stability MUST be maintained across schema updates
- Legacy schema support MUST be maintained per deprecation policy

Resiliency Testing Requirements

Fault Injection Tests
- File system errors (permissions, disk full)
- Memory pressure scenarios
- CPU saturation conditions
- Network interruption simulation
Recovery Tests
- Graceful degradation verification
- State consistency after errors
- Automatic retry mechanisms
- Circuit breaker functionality
Stress Tests
- High-volume instruction loading
- Concurrent access patterns
- Memory leak detection
- Performance under load

🛡️ Security & PII Protection (BINDING)

Security Architecture

---
config:
    layout: elk
---
graph TB
    subgraph "Security Layers"
        A[Input Validation Layer]
        B[Authentication/Authorization]
        C[Data Sanitization]
        D[Audit Logging]
        E[Encryption at Rest]
    end
    
    subgraph "Threat Protection"
        F[Injection Prevention]
        G[Path Traversal Guards]
        H[Buffer Overflow Protection]
        I[Resource Exhaustion Limits]
    end
    
    subgraph "PII Protection"
        J[PII Detection]
        K[Data Redaction]
        L[Secure Storage]
        M[Access Controls]
    end
    
    A --> F
    B --> G
    C --> H
    D --> I
    E --> J
    F --> K
    G --> L
    H --> M

Mandatory Security Requirements

Input Validation (CRITICAL)

// All inputs MUST be validated
function validateToolInput(params: unknown): ValidationResult {
  // MANDATORY: Schema validation
  const schemaResult = validateAgainstSchema(params);
  if (!schemaResult.valid) return schemaResult;
  
  // MANDATORY: Sanitization
  const sanitized = sanitizeInput(params);
  
  // MANDATORY: Business rule validation
  return validateBusinessRules(sanitized);
}

PII Detection & Protection
- MUST scan all instruction content for PII patterns
- MUST redact sensitive data before logging
- MUST implement secure storage for any retained data
- MUST provide PII purging capabilities
Authentication & Authorization
- MUST implement capability-based security model
- MUST validate all mutation operations
- MUST audit all write operations
- MUST support role-based access controls
Audit & Compliance
- MUST log all security events
- MUST maintain audit trails for compliance
- MUST implement tamper detection
- MUST support forensic analysis

PII Protection Patterns (MANDATORY)

// PII patterns that MUST be detected and protected
const PII_PATTERNS = {
  SSN: /\b\d{3}-\d{2}-\d{4}\b/g,
  EMAIL: /\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b/g,
  CREDIT_CARD: /\b\d{4}[\s-]?\d{4}[\s-]?\d{4}[\s-]?\d{4}\b/g,
  PHONE: /\b\d{3}[-.]?\d{3}[-.]?\d{4}\b/g,
  IP_ADDRESS: /\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b/g
};

// MANDATORY redaction function
function redactPII(content: string): string {
  let redacted = content;
  for (const [type, pattern] of Object.entries(PII_PATTERNS)) {
    redacted = redacted.replace(pattern, `[REDACTED_${type}]`);
  }
  return redacted;
}

📋 Change Management & Documentation

Architecture Documentation Requirements (BINDING)

Logical Diagrams (MANDATORY)
- MUST include Mermaid diagrams for all major subsystems
- MUST be GitHub dark theme compatible
- MUST be updated with every architectural change
- MUST include sequence diagrams for complex workflows
API Documentation Standards
- MUST document all tools with complete schemas
- MUST include request/response examples
- MUST specify error conditions and codes
- MUST maintain version compatibility matrices
Decision Records (MANDATORY)
- MUST document all significant architectural decisions
- MUST include rationale and alternatives considered
- MUST specify impact and migration requirements
- MUST maintain decision history and changes

Change Log Requirements (BINDING)

All changes MUST be documented in CHANGELOG.md with:

## [Version] - YYYY-MM-DD

### BREAKING CHANGES
- List all breaking changes with migration guidance

### Added
- New features and capabilities

### Changed  
- Modifications to existing functionality

### Deprecated
- Features marked for future removal

### Removed
- Features removed from the system

### Fixed
- Bug fixes and corrections

### Security
- Security-related changes and fixes

Version Management (MANDATORY)

---
config:
    layout: elk
---
graph LR
    A[Feature Branch] --> B[Pull Request]
    B --> C[Code Review]
    C --> D[Automated Tests]
    D --> E[Security Scan]
    E --> F[Integration Tests]
    F --> G[Merge to Main]
    G --> H[Version Tag]
    H --> I[Release Notes]
    I --> J[Documentation Update]

Semantic Versioning (BINDING)
- MAJOR: Breaking changes to API or protocol
- MINOR: New features without breaking changes
- PATCH: Bug fixes and maintenance
Release Process (MANDATORY)
- ALL changes require pull request review
- ALL tests MUST pass before merge
- ALL documentation MUST be updated
- ALL breaking changes MUST include migration guide

🎯 Acceptance Criteria & Quality Gates

Definition of Done (BINDING)

A feature is considered complete ONLY when:

✅ Code Requirements

Code follows TypeScript strict mode
All lint rules pass without warnings
Code coverage meets minimum thresholds
Performance benchmarks meet SLO targets

✅ Testing Requirements

Unit tests written and passing
Integration tests covering happy/error paths
Handshake tests validate protocol compliance
Performance tests verify SLO compliance

✅ Documentation Requirements

API documentation updated
Architecture diagrams updated
Security impact assessed
Change log updated

✅ Security Requirements

Security review completed
PII impact assessed
Vulnerability scan passed
Audit trail verified

Quality Gates (NON-NEGOTIABLE)

---
config:
    layout: elk
---
graph LR
    A[Code Commit] --> B{Lint Check}
    B -->|Pass| C{Unit Tests}
    B -->|Fail| X[Block]
    C -->|Pass| D{Integration Tests}
    C -->|Fail| X
    D -->|Pass| E{Security Scan}
    D -->|Fail| X
    E -->|Pass| F{Performance Test}
    E -->|Fail| X
    F -->|Pass| G[Merge Approved]
    F -->|Fail| X

Automated Gates
- Code linting (ESLint + TypeScript)
- Unit test execution (100% pass rate)
- Integration test execution (100% pass rate)
- Security vulnerability scanning
- Performance regression testing
Manual Gates
- Code review approval (minimum 2 reviewers)
- Architecture review (for significant changes)
- Security review (for sensitive changes)
- Documentation review

📊 Monitoring & Observability

Required Metrics (BINDING)

// Metrics that MUST be collected and exposed
interface RequiredMetrics {
  // Performance Metrics
  requestLatency: HistogramMetric;
  requestThroughput: CounterMetric;
  errorRate: RateMetric;
  
  // System Metrics
  memoryUsage: GaugeMetric;
  cpuUtilization: GaugeMetric;
  diskUsage: GaugeMetric;
  
  // Business Metrics
  instructionCount: GaugeMetric;
  IndexLoadTime: HistogramMetric;
  governanceHashStability: CounterMetric;
  
  // Security Metrics
  authenticationAttempts: CounterMetric;
  authorizationFailures: CounterMetric;
  piiDetections: CounterMetric;
}

Health Check Requirements (MANDATORY)

---
config:
    layout: elk
---
graph TD
    A[Health Check Request] --> B[System Health]
    B --> C[Memory Check]
    B --> D[Disk Space Check]
    B --> E[Index Integrity Check]
    
    C --> F{Memory OK?}
    D --> G{Disk OK?}
    E --> H{Index OK?}
    
    F -->|Yes| I[Healthy]
    F -->|No| J[Degraded]
    
    G -->|Yes| I
    G -->|No| J
    
    H -->|Yes| I
    H -->|No| K[Critical]
    
    I --> L[HTTP 200]
    J --> M[HTTP 503]
    K --> N[HTTP 503]

Alerting Thresholds (BINDING)

Metric	Warning	Critical	Action
Response Time P95	>100ms	>200ms	Scale/Optimize
Error Rate	>0.1%	>1%	Investigate
Memory Usage	>400MB	>500MB	Memory Leak Check
Disk Usage	>80%	>90%	Cleanup/Expand
Failed Handshakes	>0	>5	Protocol Issue

🚀 Implementation Roadmap

Phase 1: Foundation (COMPLETE)

✅ Basic MCP server implementation
✅ JSON-RPC transport layer
✅ instruction index management
✅ Schema v2 migration
✅ Basic testing framework

Phase 2: Enterprise Hardening (CURRENT)

🔄 Comprehensive test suite completion
🔄 Security implementation and PII protection
🔄 Performance optimization
🔄 Documentation standardization
🔄 Monitoring and observability

Phase 3: Advanced Features (PLANNED)

📋 Advanced search and filtering
📋 Real-time collaboration features
📋 Advanced analytics and reporting
📋 Multi-tenant architecture
📋 API versioning and backward compatibility

Phase 4: Scale & Optimization (FUTURE)

📋 Distributed architecture
📋 Horizontal scaling capabilities
📋 Advanced caching strategies
📋 Machine learning integration
📋 Enterprise integration patterns

⚠️ Risk Management & Mitigation

Technical Risks (HIGH PRIORITY)

Risk	Probability	Impact	Mitigation Strategy
MCP Protocol Breaking Changes	Medium	High	Version pinning, comprehensive protocol tests, migration guides
Performance Degradation at Scale	Medium	High	Load testing, performance monitoring, horizontal scaling design
Data Corruption/Integrity Loss	Low	Critical	Multi-layer hashing, integrity verification, automated backups
Security Vulnerabilities	Medium	Critical	Regular security audits, automated scanning, security-first development
Schema Migration Failures	Low	High	Idempotent migrations, rollback procedures, extensive testing

Business Risks (MEDIUM PRIORITY)

Risk	Probability	Impact	Mitigation Strategy
Compliance Violations	Low	High	Regular compliance audits, automated PII detection, audit trails
Vendor Lock-in (MCP Dependency)	Medium	Medium	Standard protocol adherence, abstraction layers, exit strategies
Resource Constraints	Medium	Medium	Performance budgets, resource monitoring, capacity planning

Mitigation Implementation (BINDING)

Continuous Risk Assessment: Monthly risk review with stakeholder committee
Automated Risk Detection: Integrate risk monitoring into CI/CD pipeline
Incident Response: Documented procedures for each identified risk scenario
Business Continuity: Disaster recovery and data backup procedures

📞 Governance & Compliance

Document Authority (BINDING)

This PRD serves as the binding contract for all project development activities. Any deviation from the requirements specified herein MUST be:

Formally Requested: Via structured change request process
Technically Justified: With detailed impact analysis
Security Reviewed: For security and compliance implications
Stakeholder Approved: By project governance committee
Documented: With updated PRD version and change log

Compliance Verification

Regular compliance audits MUST verify:

Code adherence to architectural standards
Test coverage meeting minimum requirements
Security controls implementation
Documentation currency and accuracy
Performance SLO compliance

Review Cycle (MANDATORY)

Quarterly Reviews: Technical implementation compliance
Semi-Annual Reviews: Security and PII protection assessment
Annual Reviews: Complete PRD relevance and update

Document Control:

Version History: Tracked in git with semantic versioning
Approval Authority: Project Technical Committee
Next Review Date: November 28, 2025
Classification: Internal Use - Technical Specification

This document represents the binding technical and process requirements for the index project. All development activities must conform to these specifications to ensure quality, security, and reliability.