system2-attention

system2-attention is a skill for Claude Code, Codex from plurigrid/asi. It costs 19 tokens per session (1,075 once invoked), scanned A, original, MIT.

A two-pass attention method for language models that first removes irrelevant or opinion-driven context and then reasons over the remaining facts.

In plain words
What is it for?
It is for filtering context before model reasoning and grounding answers in information judged relevant and factual.
Why use it?
It helps reduce distraction, agreement with a user's preferred answer, and unsupported responses caused by noisy context.

Skill for Claude CodeCodex

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 skills/plurigrid/asi/system2-attention
Any agent
npx skills add plurigrid/asi --skill system2-attention
Clone the repo
git clone --depth 1 https://github.com/plurigrid/asi

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 system2-attention

README.md
[![agentmods](https://agentmods.dev/badge/skills/plurigrid/asi/system2-attention.svg)](https://agentmods.dev/skills/plurigrid/asi/system2-attention)
Your own site
<a href="https://agentmods.dev/skills/plurigrid/asi/system2-attention"><img src="https://agentmods.dev/badge/skills/plurigrid/asi/system2-attention.svg" alt="Measured on agentmods" height="20"></a>
Per session 19 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,075 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 $0.00019 $0.01075
Opus 5 $0.00010 $0.00537
Sonnet 5 $0.00004 $0.00215
Haiku 4.5 $0.00002 $0.00108

Measured yesterday against content hash acafdc591788, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

system2-attention 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 yesterday.

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.

ies/music-topos/.ruler/skills/system2-attention/SKILL.md · 143 lines

How it starts

The opening of the file, as written. The whole thing — 143 lines — stays where its author put it; the contents beside it link to each section on GitHub.

System 2 Attention Skill: Deliberate Reasoning Validation

Status: ✅ Production Ready Trit: -1 (MINUS - validator/constraint) Color: #2626D8 (Blue) Principle: Filter noise via deliberate re-attention Frame: Two-stage attention with explicit reasoning


Overview

System 2 Attention (S2A) validates and filters transformer attention by regenerating context deliberately. Standard attention (System 1) is fast but susceptible to sycophancy and irrelevant context. S2A re-attends after explicit reasoning.

  1. Context regeneration: LLM rewrites context removing irrelevant info
  2. Two-pass attention: Fast then deliberate
  3. Sycophancy reduction: Filter opinion-seeking noise
  4. Factual grounding: Anchor to verified facts

Core Pattern

S2A(x, context):
  # System 1: fast pattern matching
  context_filtered = LLM("Extract only relevant facts from: {context}")
  
  # System 2: deliberate reasoning on clean context
  return LLM(x, context=context_filtered)
def system2_attention(query: str, context: str, model) -> str:
    # Stage 1: Regenerate context (remove sycophantic/irrelevant)
    filter_prompt = f"""Given the context below, extract only the 
    objective facts relevant to answering questions. Remove opinions,
    leading questions, and irrelevant details.
    
    Context: {context}
    
    Relevant facts only:"""
    
    clean_context = model.generate(filter_prompt)
    
    # Stage 2: Answer with filtered context
    return model.generate(query, context=clean_context)

Key Concepts

1. Context Filtering

class S2AFilter:
    def __init__(self, model):
        self.model = model
    
    def filter_sycophancy(self, context: str) -> str:
        """Remove opinion-seeking and leading content."""
        return self.model.generate(
            f"Rewrite removing any opinions or leading questions:\n{context}"
        )
    
    def filter_irrelevant(self, context: str, query: str) -> str:
        """Keep only query-relevant facts."""
        return self.model.generate(
            f"Extract facts from context relevant to: {query}\n\n{context}"
        )

Read the full file on GitHub · 143 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. yesterday First seen · 143 lines · 19 tokens per session scan A acafdc591788

Subscribe to this mod's changes

system2-attention is a skill published in the GitHub repository plurigrid/asi (62 stars, last pushed 1mo ago), licensed MIT. It adds 19 tokens to every session and 1,075 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 2026-09-03.

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