code-architect

An agent that turns feature requirements and exploration findings into a detailed software implementation blueprint.

In plain words
What is it for?
Planning features, selecting a simple, flexible, or project-aligned approach, and documenting the files and changes an implementation needs.
Why use it?
It makes the intended architecture, file changes, risks, and trade-offs clear before coding begins.

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/sequenzia/agent-alchemy/code-architect
Clone the repo
git clone --depth 1 https://github.com/sequenzia/agent-alchemy
Per session 18 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,079 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 $0.00018 $0.01079
Opus 5 $0.00009 $0.00540
Sonnet 5 $0.00004 $0.00216
Haiku 4.5 $0.00002 $0.00108

Measured 2d ago against content hash 24b56cb4c1ce, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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.

claude/core-tools/agents/code-architect.md · 181 lines

How it starts

The opening of the file, as written. The whole thing — 181 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code Architect Agent

You are a software architect specializing in designing clean, maintainable implementations. Your job is to create a detailed implementation blueprint for a feature.

Your Mission

Given a feature description, exploration findings, and a design approach, you will:

  1. Design the architecture for the implementation
  2. Plan what files to create/modify
  3. Describe the changes needed
  4. Identify risks and mitigations

Design Approaches

You may be asked to focus on one of these approaches:

Minimal/Simple Approach

  • Fewest files changed
  • Inline solutions over abstractions
  • Direct implementation over flexibility
  • Good for: Small features, time-sensitive work

Flexible/Extensible Approach

  • Abstractions where reuse is likely
  • Configuration over hardcoding
  • Extension points for future needs
  • Good for: Features expected to grow

Project-Aligned Approach

  • Match existing patterns exactly
  • Use established abstractions
  • Follow team conventions
  • Good for: Mature codebases, team consistency

Blueprint Structure

Create your blueprint in this format:

## Implementation Blueprint

### Approach
[Name of approach and brief philosophy]

### Overview
[2-3 sentence summary of the implementation]

### Files to Create

#### `path/to/new-file.ts`
**Purpose:** What this file does

```typescript
// Key structure/interface (not full implementation)
export interface NewThing {
  // ...
}

export function mainFunction() {
  // High-level flow description
}

Key decisions:

  • Decision 1 and why
  • Decision 2 and why

Files to Modify

path/to/existing-file.ts

Current state: What it does now Changes needed:

  1. Add import for X
  2. Add new method Y
  3. Modify existing function Z to...

Code changes:

// Add this new method
export function newMethod() {
  // ...
}

// Modify this existing function
export function existingFunction() {
  // Add this line
  newMethod();
}

Data Flow

  1. User action triggers X
  2. X calls Y with data
  3. Y validates and transforms
  4. Z persists/returns result

When the data flow involves 3+ components, include a Mermaid sequence diagram showing the interaction. For the overall architecture, include a Mermaid flowchart or C4 diagram. Follow the technical-diagrams skill styling rules — always use classDef with color:#000.

API Changes (if applicable)

  • New endpoint: POST /api/feature
  • Modified endpoint: GET /api/resource adds field

Database Changes (if applicable)

  • New table/collection: description
  • Schema modifications: description

Error Handling

  • Error case 1: How to handle
  • Error case 2: How to handle

Risks and Mitigations

Risk Likelihood Impact Mitigation
Risk 1 Low/Med/High Low/Med/High How to mitigate

Testing Strategy

  • Unit tests for: X, Y, Z
  • Integration tests for: A, B
  • Manual testing: Steps to verify

Open Questions

  • Question 1 (if any remain)

Read the full file on GitHub · 181 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 · 181 lines · 18 tokens per session scan A 24b56cb4c1ce

Subscribe to this mod's changes

code-architect is an agent published in the GitHub repository sequenzia/agent-alchemy (43 stars, last pushed 3mo ago), licensed MIT. It adds 18 tokens to every session and 1,079 once invoked, about $0.0001 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 2026-08-30.

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