Borrowing it
Nothing to install: this file belongs to jonathan-vella/apex-accelerator. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/jonathan-vella/apex-accelerator/main/.github/instructions/context-optimization.instructions.mdgit clone --depth 1 https://github.com/jonathan-vella/apex-acceleratorWrote 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.
[](https://agentmods.dev/instructions/jonathan-vella/apex-accelerator/context-optimization)<a href="https://agentmods.dev/instructions/jonathan-vella/apex-accelerator/context-optimization"><img src="https://agentmods.dev/badge/instructions/jonathan-vella/apex-accelerator/context-optimization/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.
<a href="https://agentmods.dev/instructions/jonathan-vella/apex-accelerator/context-optimization"><img src="https://agentmods.dev/badge/instructions/jonathan-vella/apex-accelerator/context-optimization.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.01535 | $0.01535 |
| Opus 5.5 | $0.00614 | $0.00614 |
| Sonnet 5.5 | $0.00307 | $0.00307 |
| Haiku 4.5 | $0.00153 | $0.00153 |
Grade A, and why
apex-accelerator context-optimization.instructions.md 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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 127 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Context Window Optimization Rules
Rules for keeping agent context windows efficient. These apply when creating or modifying agent definitions, skills, and instruction files.
Agent Definition Rules
Two tiers govern agent definitions: hard limits (CI-enforced — a breach
fails npm run validate:agents) and soft guidelines (advisory — keep
lean, but no validator blocks them).
Hard limits (CI-enforced)
| Rule | Limit | Enforced by |
|---|---|---|
| Agent body length | ≤ 600 lines | tools/scripts/_lib/paths.mjs (MAX_BODY_LINES) |
description length |
≤ 350 chars (warn ≥ 300) | validate-agents.mjs frontmatter check |
Soft guidelines (advisory — not CI-enforced)
| Rule | Target | Rationale |
|---|---|---|
| Tool list size | ≤ 30 tools | Schema/context cost varies by runtime; measure rather than assume a multiplier |
| Agent body length | ≤ 350 lines | Preserve role contracts and stop rules (hard cap is 600) |
| Inline template size | ≤ 50 lines | Move larger templates to skills |
| Native task scope | Bounded inputs/outputs | Active agents omit UI handoffs; preserve authorized native task routing |
| Skill references in body | ≤ 5 "Read" lines | Progressive load, not bulk load |
Instruction File Rules
| Rule | Limit / Target | Enforced? |
|---|---|---|
| File size | ≤ 150 lines (target) | Guideline — split heavy content into a skill references/ file |
applyTo: "**" file size |
≤ 50 lines | Warning only — validate-glob-audit.mjs; wildcard always warns, size adds a note |
| Broad-markdown file size | ≤ 200 lines | Warning only — validate-glob-audit.mjs for an exact recognized broad glob |
applyTo specificity |
Narrow globs | Guideline — **/*.ts not ** when possible |
Avoid applyTo: "**" |
Exceptional only | Loads for every single file match |
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.
- 6d ago Changed · +1 lines · +14 tokens per session 44d9d4974fcf
- 1mo ago Changed · -48 lines · -427 tokens per session 12ee6754a87d
- 1mo ago Changed · +4 lines · -9 tokens per session c6171151cf3a
- 1mo ago First seen · 170 lines · 1,957 tokens per session scan A a4bc0e52f0e4
apex-accelerator context-optimization.instructions.md is an instructions file published in the GitHub repository jonathan-vella/apex-accelerator (50 stars, last pushed yesterday), licensed MIT. It adds 1,535 tokens to every session, about $0.0061 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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