AI Agent Core Architectures

AI Agent Core Architectures is a skill for Claude Code, Codex from j4flmao/agent-skills. It costs 26 tokens per session (550 once invoked), scanned A, original, MIT.

A guide to the basic loop used by autonomous AI agents: take in information, reason about it, perform an action, and inspect the result. It compares ReAct, which alternates reasoning and actions, with plan-first approaches.

In plain words
What is it for?
Use it to design or compare agent workflows, especially systems that call tools, receive feedback, and repeat steps until a task is complete.
Why use it?
It gives a clear way to think about agents that interact with an environment instead of replying only once. This helps when choosing how an agent should plan and respond to new results.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to design or compare agent workflows, especially systems that call tools, receive feedback, and repeat steps until a task is complete.

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Install with agentmods
npx agentmods add skills/j4flmao/agent-skills/core-architectures
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.

Any agent
npx skills add j4flmao/agent-skills --skill core-architectures
Clone the repo
git clone --depth 1 https://github.com/j4flmao/agent-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for AI Agent Core Architectures

README.md
[![agentmods](https://agentmods.dev/badge/skills/j4flmao/agent-skills/core-architectures/github.svg)](https://agentmods.dev/skills/j4flmao/agent-skills/core-architectures)
Your own site
<a href="https://agentmods.dev/skills/j4flmao/agent-skills/core-architectures"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/core-architectures/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for AI Agent Core Architectures

Your own site · 80×15
<a href="https://agentmods.dev/skills/j4flmao/agent-skills/core-architectures"><img src="https://agentmods.dev/badge/skills/j4flmao/agent-skills/core-architectures.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 26 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 550 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00026 $0.00550
Opus 5 $0.00013 $0.00275
Sonnet 5 $0.00005 $0.00110
Haiku 4.5 $0.00003 $0.00055

Measured 9d ago against content hash 525d37b94e9b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

AI Agent Core Architectures 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 9d 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.

skills/ai/ai-agents/core-architectures/SKILL.md · 42 lines

How it starts

The opening of the file, as written. The whole thing — 42 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Core Architectures: The Autonomous Cognitive Loop

The existence of an autonomous agent is defined not by static inference, but by the continuous, recursive execution of the cognitive loop: Perceive -> Think -> Act -> Observe. This loop bridges the gap between latent semantic space and deterministic environment execution.

First Principles of Agentic Flow

Every framework-agnostic architecture reduces to this state machine. The agent's cognition is a sequence of discrete state transitions bounded by token limits and environment feedback.

  1. Perception: Ingestion of environment state. The synthesis of system prompts, historical context, and the immediate state of the world.
  2. Thought (Reasoning): The generation of latent reasoning tokens. This is the derivation of intent, mapping perception to actionable trajectory.
  3. Action: The emission of structured payloads designed to mutate the environment or retrieve novel state.
  4. Observation: The ingestion of the deterministic result of the action, closing the loop.

Architectural Paradigms

ReAct (Reason + Act)

The interleaving of reasoning traces with action execution. ReAct assumes high environmental volatility, requiring continuous recalibration. It sacrifices long-horizon coherence for immediate, localized adaptability.

Plan-and-Solve

The temporal decoupling of strategy from execution. The agent first synthesizes a comprehensive graph of execution steps, then traverses the graph sequentially. Plan-and-Solve assumes low environmental volatility but requires profound foresight. It excels in complex, multi-dependent task resolution but is brittle to unexpected state mutations during execution.

The Necessity of Self-Reflection

Without self-reflection, an agent is an open-loop controller doomed to terminal error spirals. Self-reflection acts as the error-correction mechanism, forcing the agent to evaluate the delta between expected observation and actual observation, dynamically altering its system prompt or execution graph to converge on the goal state.

Read the full file on GitHub · 42 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. 9d ago First seen · 42 lines · 26 tokens per session scan A 525d37b94e9b

Subscribe to this mod's changes

AI Agent Core Architectures is a skill published in the GitHub repository j4flmao/agent-skills (22 stars, last pushed 3d ago), licensed MIT. It adds 26 tokens to every session and 550 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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