context-engineering

context-engineering is a skill for Claude Code, Codex from a5c-ai/babysitter. It costs 28 tokens per session (515 once invoked), scanned A, original, MIT.

A context-management workflow that loads different project information depending on whether the agent is coding, reviewing, or researching.

In plain words
What is it for?
Use it to detect a project’s tools and language, selectively load architecture, code, tests, or research, inject relevant conventions, and compact completed work.
Why use it?
It reduces wasted context by prioritising relevant files and skipping information that does not help with the current task. It also preserves useful state when the conversation becomes large.

Skill for Claude CodeCodex

About the project

Babysitter is a workflow engine for AI coding agents that enforces predefined steps, quality checks, human approvals, and decision records. It is used to coordinate complex, repeatable agent workflows across supported coding tools. The catalogue contains skills, agents, instructions, settings, a plugin, and an MCP integration for its workflow.

a5c-ai/babysitter · 1,769 stars · on GitHub

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/a5c-ai/babysitter/context-engineering
Any agent
npx skills add a5c-ai/babysitter --skill context-engineering
Clone the repo
git clone --depth 1 https://github.com/a5c-ai/babysitter

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 context-engineering

README.md
[![agentmods](https://agentmods.dev/badge/skills/a5c-ai/babysitter/context-engineering.svg)](https://agentmods.dev/skills/a5c-ai/babysitter/context-engineering)
Your own site
<a href="https://agentmods.dev/skills/a5c-ai/babysitter/context-engineering"><img src="https://agentmods.dev/badge/skills/a5c-ai/babysitter/context-engineering.svg" alt="Measured on agentmods" height="20"></a>
Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 515 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 $0.00028 $0.00515
Opus 5 $0.00014 $0.00258
Sonnet 5 $0.00006 $0.00103
Haiku 4.5 $0.00003 $0.00052

Measured yesterday against content hash f5d2a9c6ef7c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 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.

library/methodologies/everything-claude-code/skills/context-engineering/SKILL.md · 63 lines

What it actually says

  • Load: architecture docs, active code files, test files, recent changes
  • Skip: historical discussions, completed milestones, research notes
  • Priority: implementation speed

Review Mode

  • Load: code diff, coding standards, security rules, test coverage
  • Skip: architecture docs, planning notes, research
  • Priority: thoroughness and accuracy

Research Mode

  • Load: requirements, existing patterns, external research, alternatives
  • Skip: implementation details, test files, CI configs
  • Priority: breadth of information

Dynamic Injection

  • Detect project context automatically (language, framework, tools)
  • Load relevant skills based on detected context
  • Inject domain-specific patterns and conventions
  • Adjust tool allowlists per context mode

Selective Loading

  • Load only files relevant to the current task
  • Use glob patterns to scope file reading
  • Prioritize recently modified files
  • Skip binary files and generated code

Strategic Compaction

  • Monitor context token usage
  • Suggest compression for resolved/completed items
  • Archive to memory files (activeContext, patterns, progress)
  • Pre-compaction state preservation
  • Automated compaction triggers at token thresholds

Cross-Platform Detection

  • Package manager: npm (package-lock.json), pnpm (pnpm-lock.yaml), yarn (yarn.lock), bun (bun.lockb)
  • Language: TypeScript (tsconfig.json), Go (go.mod), Python (pyproject.toml), Java (pom.xml)
  • Test runner: vitest, jest, pytest, go test
  • CI/CD: GitHub Actions, Dockerfile, docker-compose

When to Use

  • Session initialization (detect context)
  • Before each phase (inject relevant context)
  • Token budget warnings (strategic compaction)
  • Mode transitions (dev to review to research)

Agents Used

  • Used by all agents indirectly through context detection
  • context-engineering agent for explicit compaction analysis
Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 63 lines · 28 tokens per session scan A f5d2a9c6ef7c

Subscribe to this mod's changes

context-engineering is a skill published in the GitHub repository a5c-ai/babysitter (1,769 stars, last pushed today), licensed MIT. It adds 28 tokens to every session and 515 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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