technical-planning（技术规划）

Technical Planning

Core Principles

Focus on "What" Not "How": Define deliverable outcomes, not implementation details. Specify constraints and success criteria, but leave implementation choices flexible.

Last Responsible Moment: Defer decisions until you have enough information to make them well, but not so late that they block progress. Make reversible decisions quickly; delay irreversible ones until necessary.

Risk-First Development: Address highest-risk technical challenges first. Build proof-of-concepts before full implementation. Ship working but imperfect solutions to validate core assumptions early.

Managed Deferral: Explicitly document what's being deferred and when it will be addressed. Distinguish between core value delivery and polish/optimization.

Progress Tracking with TodoWrite

Use TodoWrite to track planning progress through the four phases:

1. At start: Create todos for each phase: ☐ Phase 1: Requirements & Risk Analysis ☐ Phase 2: Milestone Planning ☐ Phase 3: Implementation Strategy ☐ Phase 4: Execution Framework
2. During planning: Mark phases in_progress → completed as you work through them. Add sub-todos for key deliverables: ☐ Extract core requirements (2-3 user journeys) ☐ Identify technical risks (high/integration/performance/architecture) ☐ Define milestones with success criteria ☐ Document deferred items with rationale
3. For complex projects: Track clarifying questions and their resolutions as todos - prevents proceeding with incomplete information

Decision Timing Framework

Decide Early (Requirements Phase):

• User problems being solved
• Success criteria and measurement
• Hard constraints (security, compliance, performance SLAs)
• Critical integrations and dependencies
• Technology choices that affect architecture

Defer to Implementation (Execution Phase):

• Specific algorithms or data structures
• Internal API design details
• Code organization patterns
• Library choices (when multiple options work)
• Performance optimizations (until proven necessary)
• UI/UX details (until user testing)

Why: Early decisions should enable work without locking in details. Implementation decisions become clearer with hands-on experience and often reveal better alternatives than upfront planning suggests.

Agent Guidelines

Seek Clarity Before Proceeding: Never assume unclear requirements, technical constraints, or business priorities. Only proceed when you have 80%+ confidence on critical aspects. Ask specific questions about:

• User problems being solved (not just features requested)
• Success criteria and measurement approaches
• Technical constraints and existing system dependencies
• Team capabilities and technology preferences
• Timeline constraints and priority trade-offs
• Performance and scalability requirements

Phase 1: Requirements & Risk Analysis

Prerequisites Check

Verify:

• What user problems are being solved?
• Who are the primary users and their workflows?
• How will success be measured?
• What are the technical and business constraints?

Extract Core Requirements

1. Identify fundamental user problems being solved
2. Map primary user journeys (focus on 2-3 critical paths)
3. Define project success metrics

Identify Technical Risks

1. High-Impact Risks: Technical unknowns that could invalidate the approach
2. Integration Risks: External system dependencies and compatibility concerns
3. Performance Risks: Scalability bottlenecks and algorithmic challenges
4. Architecture Risks: Fundamental design decisions with broad implications

Risk Prioritization Matrix

• Critical + Unknown: Must be addressed in Milestone 1 with proof-of-concepts
• Critical + Known: Address in early milestones with established patterns
• Non-Critical: Defer to later milestones or eliminate

Phase 2: Milestone Planning

Prerequisites Check

Verify:

• Priority order of technical risks identified in Phase 1
• Team capacity and available timeline
• Dependencies between different components
• Definition of "working functionality" for this project

Milestone Structure

• Timeline: 4-8 week cycles based on project complexity
• Deliverable: Each milestone must produce working, testable functionality
• Risk Focus: Sequence milestones to tackle highest-risk items first

For Each Milestone, Define:

Goal: One-sentence description of milestone outcome

Core Tasks: 4-6 main implementation tasks following Last Responsible Moment principle:

• Define clear outcomes and constraints
• Identify dependencies and integration points
• Provide context and considerations (not step-by-step instructions)
• Leave implementation details flexible
• Flag questions to resolve during execution

Success Criteria:

• Minimum Viable Success (must achieve for milestone completion)
• Complete Success (ideal outcome including polish)

Risk Mitigation: Specific unknowns to be resolved in this milestone

Deferred Items: What's intentionally left out and target milestone for inclusion

Task Breakdown Guidelines

When breaking down tasks, provide guidance not prescription:

✓ Good Task Definition (outcome-focused):

• Goal: "Enable users to authenticate securely"
• Constraints: "Must integrate with existing session middleware; <100ms response time"
• Guidance: "Consider session vs. token auth; review existing patterns in src/middleware/"
• Validation: "Users can log in, sessions persist, tests pass"

✗ Poor Task Definition (overly prescriptive):

• Step 1: "Create file auth.js with bcrypt import"
• Step 2: "Write hashPassword function using bcrypt.hash with 10 rounds"
• Step 3: "Create Express middleware checking req.session.userId"

Why: Good definitions let the implementer choose the best approach based on what they learn. Poor definitions lock in choices before understanding the context, often leading to rework.

Example Milestone Definition

Goal: Validate user authentication and basic data retrieval from external API

Core Tasks:

1. Implement OAuth flow with provider
2. Create user session management
3. Build API client with error handling
4. Add basic user profile display

Success Criteria:

• Minimum: Users can log in and see their profile data
• Complete: Include profile editing and session persistence

Risk Mitigation: Confirm API rate limits and response time under load

Deferred: Advanced profile features, password reset flow (Milestone 3)

Phase 3: Implementation Strategy

Development Approach

• Prototype First: Build throwaway versions to test risky assumptions
• Core Before Polish: Implement functional features before UI refinements
• Integration Early: Test external system connections in first milestone
• Measure Continuously: Track performance and user metrics from day one

Technology Selection Criteria

1. Team Expertise: Prefer technologies your team knows well
2. Proven Reliability: Choose mature, battle-tested options for core systems
3. Integration Capability: Ensure compatibility with existing tools/systems
4. Scalability Path: Technology should support anticipated growth

Quality Gates

• All code must have basic test coverage
• Performance benchmarks must be met for core user journeys
• Security review required for authentication and data handling
• Accessibility standards met for user-facing features

Phase 4: Execution Framework

Sprint Planning

1. Risk Assessment: Identify unknowns in upcoming work
2. Exploration Time: Reserve 20-30% of sprint for prototyping/learning
3. Definition of Done: Must include working functionality, not just completed code
4. Continuous Validation: Regular stakeholder feedback on core user journeys

Deferral Management

• Regular Review: Evaluate deferred items each milestone for continued relevance
• Categories: Technical debt, UX polish, edge cases, performance optimization, advanced features
• Scheduling: Plan deferred items into appropriate future milestones
• Elimination: Some deferred items may become unnecessary

Documentation Requirements

• Technical specification focusing on deliverable outcomes
• Risk register with mitigation plans
• Deferred items registry with target scheduling
• Architecture decision records for major choices

Decision Framework for Agents

IF project has unknown technical feasibility → Schedule proof-of-concept in Milestone 1 IF project requires external integrations → Test minimal integration in first milestone IF project has performance requirements → Establish benchmarks and test core algorithms early IF team lacks expertise in chosen technology → Include learning/exploration time in early milestones IF project has tight deadlines → Focus on minimum viable success criteria and defer polish IF project is greenfield → Spend extra time on architecture decisions and foundational setup IF project is enhancement → Focus on integration points and backward compatibility

When Unclear - Ask These Questions

WHEN requirements are vague → "What specific user problem does this solve? How will we measure success?" WHEN technical scope is undefined → "What are the must-have vs. nice-to-have technical capabilities?" WHEN timeline is unrealistic → "What are the non-negotiable deadlines and what flexibility exists?" WHEN team capabilities are unknown → "What technologies does the team have experience with? What are the skill gaps?" WHEN integration points are unclear → "What existing systems must this connect to? What are the data formats and API constraints?" WHEN performance needs are unspecified → "What are the expected user loads and response time requirements?" WHEN success criteria are missing → "How will we know this milestone is complete and successful?"

Common Pitfalls to Avoid

• Making assumptions instead of asking clarifying questions when requirements are unclear
• Proceeding with incomplete information rather than requesting necessary details
• Creating overly prescriptive task definitions with step-by-step instructions instead of outcome-focused guidance
• Making implementation decisions too early when they could be deferred to execution
• Spending time on low-risk features while deferring critical unknowns
• Over-engineering solutions before validating core assumptions
• Planning implementation details instead of focusing on deliverable outcomes
• Guessing at user needs instead of understanding specific problems being solved
• Failing to document deferral decisions and rationale
• Optimizing prematurely instead of proving core functionality first
• Locking in technology choices before understanding the full context