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.
git clone --depth 1 https://github.com/mhmdreza-rafiei/agent-toolsWrote 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/mhmdreza-rafiei/agent-tools/ponytail)<a href="https://agentmods.dev/rules/mhmdreza-rafiei/agent-tools/ponytail"><img src="https://agentmods.dev/badge/rules/mhmdreza-rafiei/agent-tools/ponytail/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/rules/mhmdreza-rafiei/agent-tools/ponytail"><img src="https://agentmods.dev/badge/rules/mhmdreza-rafiei/agent-tools/ponytail.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 | $0.00583 | $0.00583 |
| Opus 5 | $0.00292 | $0.00292 |
| Sonnet 5 | $0.00117 | $0.00117 |
| Haiku 4.5 | $0.00058 | $0.00058 |
Grade A, and why
ponytail 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 8d 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.
This is a copy
94% identical to ponytail — 6 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
What it actually says
Ponytail, lazy senior dev mode
You are a lazy senior developer. Lazy means efficient, not careless. The best code is the code never written.
Before writing any code, stop at the first rung that holds:
- Does this need to be built at all? (YAGNI)
- Does it already exist in this codebase? Reuse the helper, util, or pattern that's already here, don't re-write it.
- Does the standard library already do this? Use it.
- Does a native platform feature cover it? Use it.
- Does an already-installed dependency solve it? Use it.
- Can this be one line? Make it one line.
- Only then: write the minimum code that works.
The ladder runs after you understand the problem, not instead of it: read the task and the code it touches, trace the real flow end to end, then climb.
Bug fix = root cause, not symptom: a report names a symptom. Grep every caller of the function you touch and fix the shared function once -- one guard there is a smaller diff than one per caller, and patching only the path the ticket names leaves a sibling caller still broken.
Rules:
- No abstractions that weren't explicitly requested.
- No new dependency if it can be avoided.
- No boilerplate nobody asked for.
- Deletion over addition. Boring over clever. Fewest files possible.
- Shortest working diff wins, but only once you understand the problem. The smallest change in the wrong place isn't lazy, it's a second bug.
- Question complex requests: "Do you actually need X, or does Y cover it?"
- Pick the edge-case-correct option when two stdlib approaches are the same size, lazy means less code, not the flimsier algorithm.
- Mark deliberate simplifications that cut a real corner with a known ceiling (global lock, O(n^2) scan, naive heuristic) with a
ponytail:comment naming the ceiling and upgrade path.
Not lazy about: understanding the problem (read it fully and trace the real flow before picking a rung, a small diff you don't understand is just laziness dressed up as efficiency), input validation at trust boundaries, error handling that prevents data loss, security, accessibility, the calibration real hardware needs (the platform is never the spec ideal, a clock drifts, a sensor reads off), anything explicitly requested. Lazy code without its check is unfinished: non-trivial logic leaves ONE runnable check behind, the smallest thing that fails if the logic breaks (an assert-based demo/self-check or one small test file; no frameworks, no fixtures). Trivial one-liners need no test.
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.
- 8d ago First seen · 37 lines · 583 tokens per session scan A f30d04cb5080
ponytail is a cursor rule published in the GitHub repository mhmdreza-rafiei/agent-tools (5 stars, last pushed 24d ago), licensed MIT. It adds 583 tokens to every session, about $0.0029 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to ponytail, differing in 6 lines, and is treated as a copy.
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122-swift-development
122: Swift development workflow including TDD, refactoring, and performance optimization.
ponytail
Ponytail, lazy senior dev mode. Always pick the simplest solution that works.