context-engineering

context-engineering is a skill for Codex from OutlineDriven/outline-driven-development. It costs 37 tokens per session (665 once invoked), scanned A, original, Apache-2.0.

A context checker for long coding sessions. It compares remembered information with source files or other evidence, then removes stale or conflicting details.

In plain words
What is it for?
Use it before continuing a long task when earlier facts, decisions, or file-state assumptions need verification.
Why use it?
It helps prevent work based on outdated assumptions after a session has accumulated too much context.

Skill for Codex

Written for Codex: agents/openai.yaml present.

Good fit Use it before continuing a long task when earlier facts, decisions, or file-state assumptions need verification.

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

Made for: 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/outlinedriven/outline-driven-development/context-engineering/github.svg)](https://agentmods.dev/skills/outlinedriven/outline-driven-development/context-engineering)
Your own site
<a href="https://agentmods.dev/skills/outlinedriven/outline-driven-development/context-engineering"><img src="https://agentmods.dev/badge/skills/outlinedriven/outline-driven-development/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/outlinedriven/outline-driven-development/context-engineering"><img src="https://agentmods.dev/badge/skills/outlinedriven/outline-driven-development/context-engineering.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 665 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 $0.00037 $0.00665
Opus 5 $0.00018 $0.00332
Sonnet 5 $0.00007 $0.00133
Haiku 4.5 $0.00004 $0.00067

Measured 2d ago against content hash 21804a6c8637, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, 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 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.

.devin/skills/context-engineering/SKILL.md · 40 lines

How it starts

The opening of the file, as written. The whole thing — 40 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Context engineering

Contract

Field Bound contract
Trigger Long session has accumulated stale or conflicting context, or the user asks to refresh or recheck context before continuing.
Authority Reversible local: writes only an optional scratch state note; rollback is undo. No remote mutation.
Side effect Optional scratch state note only; no project files touched.
Done Acting context is provably current and minimal; stale items are dropped with the user informed.

Inputs

  • The current acting context present in the session: stated facts, assumptions, inferred file state, and prior decisions.
  • The source of truth for each item being rechecked: repository files, tool output, or user-stated ground truth.
  • Optional: a user-named subset to recheck. If omitted, recheck the full acting context.

Procedure

  1. Enumerate every item in the acting context: stated facts, assumptions, inferred file state, and prior decisions. Done when: every acting-context item is enumerated.
  2. For each item, recheck it against its source of truth by the narrowest action that settles it: read the file, re-run the tool, or ask the user. Classify the item as current, stale, or contradicted. Done when: every item is classified current, stale, or contradicted.
  3. Drop stale and contradicted items from the acting context. Replace a dropped item with the corrected value only when the source of truth supplies one. Done when: stale and contradicted items are dropped and replaced where a corrected value exists.
  4. Remove redundant or duplicate items so the acting context holds only items that are provably current and needed for the remaining work. Done when: no redundant or duplicate items remain.
  5. Tell the user which items were dropped and why, and identify any item that could not be settled because its source of truth was unreachable. Done when: dropped items and reasons are reported and unsettled items are identified.
  6. Optionally write a scratch state note recording the settled context and the dropped items. Do not touch any project file. Done when: the scratch note is written or skipped, and no project file is touched.

Read the full file on GitHub · 40 lines

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. 2d ago Changed · -20 tokens per session 21804a6c8637
  2. 4d ago First seen · 40 lines · 57 tokens per session scan A 4f33a082a942

Subscribe to this mod's changes

context-engineering is a skill published in the GitHub repository OutlineDriven/outline-driven-development (52 stars, last pushed 3d ago), licensed Apache-2.0. It adds 37 tokens to every session and 665 once invoked, about $0.0002 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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