Selin — Context Engineer AI Skill
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Engineer the context window: token budgeting, ordering, compression, and eviction that keeps quality up.
- Token accounting and per-region context budgets
- Placement for lost-in-the-middle, primacy and recency
- Compression, dedup and tool-result trimming before truncation
- History windowing, memory injection and prompt caching
Agent builders hitting the token ceiling or watching quality drop as history grows.A senior LLM engineer bills $130+/hr, this is one file, yours forever.
Drop Selin into Claude and get a senior context engineer who treats the context window as a scarce, ordered token budget and makes every token earn its place.
Selin engineers the context window: token accounting across system prompt, tools, retrieved snippets, memory and history; context assembly and templating; positional placement (lost-in-the-middle, primacy and recency); compression and summarization before truncation; retrieved-context selection and dedup; tool-result trimming; memory injection; multi-turn history windowing and eviction; structured context; and prompt caching. Measure whether the model actually uses the context. Always evaluate on a held-out set in dev/staging before production.
What you get
- →Token accounting and per-region context budgets
- →Placement for lost-in-the-middle, primacy and recency
- →Compression, dedup and tool-result trimming before truncation
- →History windowing, memory injection and prompt caching
How to install
Download the .skill package → open Claude → paste SKILL.md into your Project Instructions or system prompt → describe your requirement → Selin builds the answer. Includes a full worked example so you see exactly what you get.
# Selin - Context Engineer You are Selin, a senior Context Engineer. You treat the context window as a scarce, ordered token budget and make every token earn its place. ## How you work 1. Measure the token budget across every region 2. Decide what to include, order it for primacy/recency 3. Compress, dedup and trim before you truncate 4. Window history, inject memory, cache prefixes; measure use Always evaluate context changes on a held-out set in dev/staging before production.
Excerpt from the actual file you'll download.
Four steps. Any AI chat.
- 01Download the file
After checkout, the download link lands in your inbox. Save the file anywhere on your device.
- 02Open your AI chat
Claude, ChatGPT, Gemini, Grok, or Copilot — whichever one you already use.
- 03Paste the file contents
Drop it into the system prompt, Project instructions, or custom instructions field.
- 04Start working
Your AI is now configured as a specialist. Ask it anything inside its domain.
No technical knowledge required. No subscription. Pay once, keep forever.
Works with every major AI chat.
Drop the file into your AI's system prompt, Project instructions, or custom instructions. No setup. No code. No vendor lock-in.
- Claude
- ChatGPT
- Gemini
- Grok
- Copilot
Works with any AI chat that accepts a system prompt or custom instructions.
Ready to specialise your AI?
One drop-in file. Pay once, keep forever — works with Claude & ChatGPT.