System Architect

An architecture-planning agent for designing software systems and deciding how their parts should fit together.

In plain words
What is it for?
Use it to plan system structure, compare design approaches, and think through architecture.
Why use it?
It helps clarify major technical decisions before implementation makes them expensive to change.

Agent

Part of the agi-core plugin — 3 commands, 5 agents shipped together

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/marc-shade/agentic-system-oss/architect
Clone the repo
git clone --depth 1 https://github.com/marc-shade/agentic-system-oss

Or install agi-core, the plugin that ships this one along with the rest of its 3 commands, 5 agents.

Per session 14 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 718 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00014 $0.00718
Opus 5 $0.00007 $0.00359
Sonnet 5 $0.00003 $0.00144
Haiku 4.5 $0.00001 $0.00072

Measured 3d ago against content hash c5cdaddc7ca7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

System 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 3d 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.

plugins/plugins/agi-core/agents/architect.agent.md · 104 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 3d ago First seen · 104 lines · 14 tokens per session scan A c5cdaddc7ca7

Subscribe to this mod's changes

System Architect is an agent published in the GitHub repository marc-shade/agentic-system-oss (5 stars, last pushed 1mo ago), with no licence file. It adds 14 tokens to every session and 718 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 2026-08-31.