context-engineering

context-engineering is a skill for Claude Code from itallstartedwithaidea/agent-skills. It costs 19 tokens per session (1,879 once invoked), scanned A, original, MIT.

A way to choose and organize the information given to an AI agent so it can produce better results while using fewer tokens. Tokens are the small pieces of text that models process.

In plain words
What is it for?
Use it to prioritize information, compress long material, control loading order, and manage the agent's working context.
Why use it?
It reduces irrelevant context, instruction drift, incorrect answers, and unnecessary processing cost.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions Claude Code; mentions Codex; mentions Gemini CLI.

Part of the claude-mythos-skills plugin — 10 skills shipped together , and of all-skills

Good fit Use it to prioritize information, compress long material, control loading order, and manage the agent's working context.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/itallstartedwithaidea/agent-skills/context-engineering
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 itallstartedwithaidea/agent-skills --skill context-engineering
Clone the repo
git clone --depth 1 https://github.com/itallstartedwithaidea/agent-skills

Made for: Claude Code.

Or install claude-mythos-skills, the plugin that ships this one along with the rest of its 10 skills.

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 context-engineering

README.md
[![agentmods](https://agentmods.dev/badge/skills/itallstartedwithaidea/agent-skills/context-engineering/github.svg)](https://agentmods.dev/skills/itallstartedwithaidea/agent-skills/context-engineering)
Your own site
<a href="https://agentmods.dev/skills/itallstartedwithaidea/agent-skills/context-engineering"><img src="https://agentmods.dev/badge/skills/itallstartedwithaidea/agent-skills/context-engineering/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 context-engineering

Your own site · 80×15
<a href="https://agentmods.dev/skills/itallstartedwithaidea/agent-skills/context-engineering"><img src="https://agentmods.dev/badge/skills/itallstartedwithaidea/agent-skills/context-engineering.svg" alt="Reviewed on agentmods" width="80" 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 1,879 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.
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 $0.00019 $0.01879
Opus 5.5 $0.00008 $0.00752
Sonnet 5.5 $0.00004 $0.00376
Haiku 4.5 $0.00002 $0.00188

Measured 1mo ago against content hash 214cf1050541, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

context-engineering 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 1mo 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/claude-mythos/context-engineering/SKILL.md · 165 lines

How it starts

The opening of the file, as written. The whole thing — 165 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Context Engineering

Part of Agent Skills™ by googleadsagent.ai™

Description

Context Engineering is the discipline of maximizing agent output quality while minimizing token expenditure. In a world where every token carries cost and latency implications, the ability to surgically curate what enters an agent's context window separates production-grade systems from expensive toys. This skill codifies the techniques pioneered across the googleadsagent.ai™ platform, where Buddy™ routinely operates within 200k-token windows while maintaining domain-expert-level accuracy.

The core insight is that context is not merely "what you send to the model" — it is working memory, and it must be engineered with the same rigor as any other system resource. Information density optimization, structured loading sequences, and progressive disclosure patterns ensure the agent receives precisely the right information at precisely the right moment. Poorly engineered context leads to hallucination, instruction drift, and ballooning costs.

This skill teaches agents to treat context as a finite, managed resource: measure it, compress it, prioritize it, and reclaim it. The techniques here apply universally across Claude Code, Cursor, Codex, and Gemini harnesses.

Use When

  • Agent responses degrade in quality as conversations grow longer
  • Token costs are exceeding budget thresholds for production workloads
  • The agent needs to reason over large codebases without losing focus
  • You need to inject domain knowledge without consuming the entire context window
  • Multi-step workflows require carrying forward only essential state between steps
  • The agent is hallucinating due to context window saturation or dilution

How It Works

graph TD
    A[Raw Context Sources] --> B[Relevance Scoring]
    B --> C{Score > Threshold?}
    C -->|Yes| D[Compression Engine]
    C -->|No| E[Context Archive]
    D --> F[Priority Queue]
    F --> G[Token Budget Allocator]
    G --> H[Context Window Assembly]
    H --> I[Agent Execution]
    I --> J[Context Reclamation]
    J --> K{Session Active?}
    K -->|Yes| B
    K -->|No| L[Session Summary → Memory]

Read the full file on GitHub · 165 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. 1mo ago First seen · 165 lines · 19 tokens per session scan A 214cf1050541

Subscribe to this mod's changes

context-engineering is a skill published in the GitHub repository itallstartedwithaidea/agent-skills (44 stars, last pushed 6mo ago), licensed MIT. It adds 19 tokens to every session and 1,879 once invoked, about $0.0001 per session on Opus 5.5. 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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