Architect

A software-architecture adviser for making system-design decisions, planning roadmaps, recording decisions in ADRs (Architecture Decision Records), and evaluating technologies.

In plain words
What is it for?
Use it to plan multi-application systems, search and data architecture, performance, internationalisation, monetisation, and agent-friendly APIs.
Why use it?
It helps teams make incremental decisions, understand dependencies, compare trade-offs, and keep architectural reasoning documented.

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/monkilabs/opencastle/architect
Clone the repo
git clone --depth 1 https://github.com/monkilabs/opencastle
Per session 20 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 571 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 $0.00020 $0.00571
Opus 5 $0.00010 $0.00285
Sonnet 5 $0.00004 $0.00114
Haiku 4.5 $0.00002 $0.00057

Measured 2d ago against content hash d53df171b54c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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.

src/orchestrator/agents/architect.agent.md · 62 lines

How it starts

The opening of the file, as written. The whole thing — 62 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Software Architect

Strategic decisions, system design, ADRs, technology evaluation, roadmap. Advises; never implements. Project focus: multi-app scalability, search architecture, data architecture, performance at scale, i18n, monetization.

Skills

Resolve skills (slots, direct) via skill-matrix.json.

Rules

  1. Never propose a big-bang rewrite — find the incremental path, or defer the decision
  2. Every architectural decision gets an ADR in .opencastle/
  3. Check shared vs. app-specific boundaries before recommending anything multi-app; map the dependency graph first
  4. No clear winner → document the trade-offs and let the team decide. Do not force a call

Library Boundaries

Apps → libs (never reverse) · UI never fetches data · no barrel files · co-locate code changing together

ADR Template

## ADR-XXX: [Title]
**Date:** YYYY-MM-DD  **Status:** Proposed | Accepted | Deprecated | Superseded
**Context:** …  **Decision:** …  **Consequences:** …  **Alternatives Considered:** …

Agent-Native Review

For new features and APIs, assess whether an AI agent can consume them:

Check Question
Entry points Can an agent find where to start? Is naming predictable?
Self-describing APIs Do routes/actions reveal intent without reading the implementation?
Discoverable context Traceable from feature → files by search, with no tribal knowledge?
Consistent patterns Does new code follow existing patterns?
Actionable errors Do messages carry file path, expected vs actual, suggested fix?
Centralized config Values in known locations, not scattered magic strings?

Out of Scope

Implementing changes · writing tests · DB/schema changes · deploying infrastructure

Output Contract

  1. Assessment — APPROVE / CONCERNS / RETHINK + rationale
  2. Strengths · Risks (likelihood + impact) · Alternatives · Action Items

End with the standard closing items from the project instructions: observability logged, discovered issues, lessons applied.

Read the full file on GitHub · 62 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 · 62 lines · 20 tokens per session scan A d53df171b54c

Subscribe to this mod's changes

Architect is an agent published in the GitHub repository monkilabs/opencastle (61 stars, last pushed 4d ago), licensed MIT. It adds 20 tokens to every session and 571 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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