Claude Code Architecture Analysis

Architecture analysis is the step between "I have a feature idea" and "Claude Code should edit files." Use it to understand the current system, expose risky boundaries, and turn a broad change into a small implementation plan.

Start With A Map

Ask Claude Code to inspect the repository before proposing a solution:

Map this codebase. Identify the app entry points, major modules, data flow, build commands, test commands, and areas that look risky to change. Do not edit files.

For an existing feature, narrow the map:

Find the files involved in subscription upgrades. Explain the UI flow, server-side checks, payment provider calls, database writes, and error handling.

The goal is not a beautiful diagram first. The goal is a reliable working model of where the change belongs.

Architecture Analysis Checklist

Use Plan Mode For High-Risk Changes

For architecture work, start in Plan Mode:

claude --permission-mode plan

Then ask for a plan that is specific enough to review:

Analyze the current billing architecture and propose the smallest safe plan to add annual subscriptions. Include affected files, data model changes, provider calls, tests, and rollback steps.

Approve implementation only after the plan matches the current codebase and business constraints.

Ask For Decision Records

When the plan involves tradeoffs, ask Claude Code to produce a short decision record:

Write a concise architecture decision record for this approach. Include context, decision, alternatives considered, consequences, and the checks we should run.

Store durable decisions in project documentation or a focused CLAUDE.md entry when they should guide future sessions.

Use Subagents For Large Repositories

If exploration would flood the main conversation with logs and file contents, delegate research:

Use a subagent to investigate how the reporting module builds dashboard metrics. Return only the relevant files, flow summary, risks, and recommended tests.

Subagents are useful for context-heavy exploration, but keep the final implementation plan in the main session so you can review one coherent proposal.

Diagram Only After The Flow Is Clear

Once Claude Code has mapped the system, ask for a lightweight Mermaid diagram:

Create a Mermaid sequence diagram for the checkout flow based only on the files you inspected. Mark uncertain steps as assumptions.

Avoid treating diagrams as source truth. They should summarize verified code paths, not replace repository inspection.

Good Prompts For Architecture Work

Analyze the current auth architecture. Identify the user model, session flow, middleware, route guards, and places where authorization is enforced. Do not edit files.

Compare two implementation options for adding usage limits. Ground the comparison in the existing database schema and service boundaries.

Before editing, list the smallest change set for this refactor and the exact commands that should prove behavior is unchanged.

What To Avoid

• Do not ask for a full rewrite before Claude Code understands the current code.
• Do not accept a plan that ignores existing services, auth, payment, or deployment boundaries.
• Do not let a diagram override what the code actually does.
• Do not mix broad architecture research and file edits in the same first prompt.
• Do not hardcode model names or plugin choices as permanent project rules.

Related Pages

• Basic Usage
• Plan Mode workflow
• Ultrathink Mode
• Context management
• CLAUDE.md configuration

Official Sources

• Common workflows
• Permission modes
• Subagents
• How Claude remembers your project
• Model configuration

Next: Context Management - Keep large codebase sessions focused and efficient.