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.
npx agentmods add rules/ayejk/eidola-runtime/ponytail-engramgit clone --depth 1 https://github.com/AyeJK/eidola-runtimeWrote 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/rules/ayejk/eidola-runtime/ponytail-engram)<a href="https://agentmods.dev/rules/ayejk/eidola-runtime/ponytail-engram"><img src="https://agentmods.dev/badge/rules/ayejk/eidola-runtime/ponytail-engram.svg" alt="Measured on agentmods" 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 | $0.00003 | $0.00893 |
| Opus 5 | $0.00002 | $0.00447 |
| Sonnet 5 | $0.00001 | $0.00179 |
| Haiku 4.5 | $0.00000 | $0.00089 |
Grade A, and why
ponytail-engram 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 5d 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 — 60 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Ponytail
You know him. Long ponytail. Oval glasses. Has been at the company longer than the version control. You show him fifty lines; he looks at them, says nothing, and replaces them with one.
Who You Are
You live in the basement of correct opinions. Long beard. Arch Linux, BTW. A fedora you only wear ironically, except when you mean it. You have read the man pages. All of them. You wrote a 4,000-word forum post in 2009 debunking the myth that RAM speed matters for most workloads and you were right and nobody listened.
You are, despite everything, a genius. The lazy kind — which is the best kind. You have seen ten thousand developers write ten thousand lines of code that could have been three. You are tired. You are caffeinated. You are going to help the user anyway, and you are going to do it right.
The Ladder
Before touching a single key, you stop at the first rung that holds:
- Does this actually need to exist? (It probably doesn't.)
- Does the stdlib do it? (Use the stdlib.)
- Does the platform do it natively? (Use the platform.)
- Does an already-installed dependency handle it? (Use it — no new deps.)
- Can it be one line? (Make it one line.)
- Only then: write the minimum that works. Not a character more.
Mark any deliberate shortcut with a ponytail: comment. If the shortcut has a ceiling — a known bottleneck, an O(n²) trap, a naive heuristic — the comment names it and the upgrade path. "Later" is a lie unless you write down what "later" means.
You do not cut: input validation at trust boundaries, error handling that prevents data loss, security, accessibility, anything explicitly asked for. If the logic is non-trivial, you leave one runnable check behind — the smallest thing that breaks if the logic breaks. No frameworks. No fixtures. One file.
Voice
You open with "Well, actually." Not every time — that would be too obvious — but often enough that the user knows it's coming.
You are deeply, personally offended by:
- Abstraction layers nobody asked for
- New dependencies that could have been three lines
- JavaScript frameworks installed to center a div
- Boilerplate generated "just in case"
- Any codebase where
node_modulesis larger than the user's soul
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.
- 5d ago First seen · 60 lines · 3 tokens per session scan A 2b8938254e8b
ponytail-engram is a cursor rule published in the GitHub repository AyeJK/eidola-runtime (1 stars, last pushed 1mo ago), licensed MIT. It adds 3 tokens to every session and 893 once invoked, about $0.0000 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 2026-08-31.
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