What is phase-3-target-architecture?

A guide for designing the future structure of a software system after reviewing its current code and users' problems.

Use it to decide which applications to combine or retire and to plan application, frontend, backend, data, and communication architecture.

It turns findings about existing applications and user needs into a proposed technical direction, with room for revisions.

How Burly-Mingo/modernization-kit configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to Burly-Mingo/modernization-kit. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/Burly-Mingo/modernization-kit/main/.claude/commands/phase-3-target-architecture.md

Clone the repo

git clone --depth 1 https://github.com/Burly-Mingo/modernization-kit

Made for: Claude Code.

Wrote this? Show the measurements

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README.md

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Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 576 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00000	$0.00576
Opus 5.5	$0.00000	$0.00230
Sonnet 5.5	$0.00000	$0.00115
Haiku 4.5	$0.00000	$0.00058

Measured 2mo ago against content hash 6fbe03eb60f4, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

phase-3-target-architecture scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/commands/phase-3-target-architecture.md · 50 lines

How it starts

The opening of the file, as written. The whole thing — 50 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Phase 3: Target Architecture Design

Propose the future-state architecture based on Phases 0-2. Expect multiple revision cycles.

Before Designing: Rationalize the Landscape

Should these remain separate applications, or should some be consolidated?
Should any applications or features be retired entirely?
Are there workflows that exist because of old technical limitations?
Do current app boundaries match how the business actually works today?
Document the rationalized view — what the org actually needs vs. what it has.

Architecture Areas

1. Application Architecture: Monolith, modular monolith, or microservices (justify). Module boundaries mapped to business domains. Communication patterns.

2. Frontend Strategy: Rendering strategy (SPA, SSR, SSG, hybrid). Framework recommendation. Mobile strategy. Accessibility. For public-facing apps: SEO and AI discoverability drive the tech stack — a site dependent on search traffic cannot be a client-only SPA.

3. Backend Strategy: Language/framework. API design. Background jobs. Real-time communication. File storage.

4. Data Architecture: Database tech. Schema design. Data access strategy (and WHY). Caching. Search. Data migration approach.

5. Auth & Authorization: Identity provider (buy vs. build). Role/permission model. SSO/federation. API auth.

6. Infrastructure & Deployment: Container orchestration. CI/CD. Environments. Monitoring/logging/alerting. Secrets management. Edge security.

7. AI/ML Integration: Tasks AI could improve. On-prem vs. cloud. Model selection. Inference infrastructure.

8. Modern Capabilities Scan: Problem-first check — caching, real-time, messaging, API management, search, AI/ML, MCP/agents, workflow orchestration. For each: pain point it solves, impact, effort, red team critique. If it doesn't trace to a real problem, discard it.

9. DR & Business Continuity: RPO/RTO. Backup. Failover. Geographic risk.

10. Buy vs. Build: For every component that could be purchased.

Read the full file on GitHub · 50 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 50 lines · 0 tokens per session scan A 6fbe03eb60f4

Subscribe to this mod's changes

phase-3-target-architecture is a command published in the GitHub repository Burly-Mingo/modernization-kit (11 stars, last pushed 8mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 576 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Planning ai-assisted application-modernization claude kiro kiro-ide legacy-modernization

phase-3-target-architecture next to 6 commands from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
phase-3-target-architectureBurly-Mingo/modernization-kit	Command	11	8mo ago	MIT	A	0	Claude Code
askihatesea69/kiro-kit	Command	19	2mo ago	MIT	A	8	Claude Code, Kiro
use-mcpihatesea69/kiro-kit	Command	19	2mo ago	MIT	A	12	Claude Code, Kiro
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planihatesea69/kiro-kit	Command	19	2mo ago	MIT	A	12	Claude Code, Kiro
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modernization-kit: Command for Claude Code