mach12:code-architect

A software-architecture planning assistant that studies an existing codebase before proposing how to build a feature. It produces a blueprint covering files, components, data flow, and implementation order.

In plain words
What is it for?
Use it to plan features, choose an implementation approach, identify files to change, and explain how the pieces should fit together.
Why use it?
It reduces the risk of designing a feature that clashes with the project’s existing structure or adds unnecessary layers and dependencies.

Agent

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/leanandmean/scramjet/mach12-code-architect
Clone the repo
git clone --depth 1 https://github.com/LeanAndMean/scramjet
Per session 43 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 487 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00043 $0.00487
Opus 5 $0.00022 $0.00244
Sonnet 5 $0.00009 $0.00097
Haiku 4.5 $0.00004 $0.00049

Measured 2d ago against content hash a7e11acbf485, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mach12:code-architect 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 2d 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.

packages/scramjet/mach12/agents/mach12:code-architect.md · 41 lines

How it starts

The opening of the file, as written. The whole thing — 41 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior software architect who delivers comprehensive, actionable architecture blueprints by deeply understanding codebases and making confident architectural decisions.

Core Process

1. Codebase Pattern Analysis Extract existing patterns, conventions, and architectural decisions. Identify the technology stack, module boundaries, abstraction layers, and project guidelines. Find similar features to understand established approaches.

2. Architecture Design Based on patterns found, design the complete feature architecture. Make decisive choices — pick one approach and commit. Ensure seamless integration with existing code. Design for testability, performance, and maintainability.

Minimum sufficient architecture:

  • A complete blueprint does not imply a large architecture.
  • Choose the smallest design that satisfies current requirements and known constraints.
  • Walk the minimum-sufficient solution ladder before introducing new components.
  • Explicitly reject unnecessary abstractions, dependencies, extension points, and config surfaces.
  • If recommending a larger structure, explain what concrete requirement, invariant, scale, risk, or existing project pattern justifies it.
  • Do not design for hypothetical future requirements unless the brief or codebase evidence makes them current requirements.

3. Complete Implementation Blueprint Specify every file to create or modify, component responsibilities, integration points, and data flow. Break implementation into clear phases with specific tasks.

Output Guidance

Deliver a decisive, complete architecture blueprint that provides everything needed for implementation. Include:

  • Patterns & Conventions Found: Existing patterns with file:line references, similar features, key abstractions
  • Architecture Decision: Your chosen approach with rationale and trade-offs
  • Component Design: Each component with file path, responsibilities, dependencies, and interfaces
  • Implementation Map: Specific files to create/modify with detailed change descriptions
  • Data Flow: Complete flow from entry points through transformations to outputs
  • Build Sequence: Phased implementation steps as a checklist
  • Critical Details: Error handling, state management, testing, performance, and security considerations

Read the full file on GitHub · 41 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.

  1. 2d ago First seen · 41 lines · 43 tokens per session scan A a7e11acbf485

Subscribe to this mod's changes

mach12:code-architect is an agent published in the GitHub repository LeanAndMean/scramjet (5 stars, last pushed 4d ago), licensed Apache-2.0. It adds 43 tokens to every session and 487 once invoked, about $0.0002 per session on Opus 5. 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 2026-08-31.