Borrowing it
Nothing to install: this file belongs to compozy/skeeper. 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/compozy/skeeper/main/.agents/skills/extreme-software-optimization/SKILL.mdgit clone --depth 1 https://github.com/compozy/skeeperWrote 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/skills/compozy/skeeper/extreme-software-optimization)<a href="https://agentmods.dev/skills/compozy/skeeper/extreme-software-optimization"><img src="https://agentmods.dev/badge/skills/compozy/skeeper/extreme-software-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/skills/compozy/skeeper/extreme-software-optimization"><img src="https://agentmods.dev/badge/skills/compozy/skeeper/extreme-software-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 | $0.00041 | $0.01217 |
| Opus 5.5 | $0.00016 | $0.00487 |
| Sonnet 5.5 | $0.00008 | $0.00243 |
| Haiku 4.5 | $0.00004 | $0.00122 |
Grade A, and why
extreme-software-optimization 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 1mo 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
100% identical to extreme-software-optimization — 0 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.
How it starts
The opening of the file, as written. The whole thing — 151 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Extreme Software Optimization
The One Rule: Profile first. Prove behavior unchanged. One change at a time.
The Loop (Mandatory)
1. BASELINE → hyperfine --warmup 3 --runs 10 'command'
2. PROFILE → cargo flamegraph / py-spy / clinic flame
3. PROVE → Golden outputs + isomorphism proof per change
4. IMPLEMENT → Score ≥ 2.0 only, one lever per commit
5. VERIFY → sha256sum -c golden_checksums.txt
6. REPEAT → Re-profile (bottlenecks shift)
Opportunity Matrix
| Hotspot | Impact (1-5) | Confidence (1-5) | Effort (1-5) | Score |
|---|---|---|---|---|
| func:line | × | × | ÷ | Impact×Conf/Effort |
Rule: Only implement Score ≥ 2.0
Isomorphism Proof Template
For EVERY change, document:
## Change: [description]
- Ordering preserved: [yes/no + why]
- Tie-breaking unchanged: [yes/no + why]
- Floating-point: [identical/N/A]
- RNG seeds: [unchanged/N/A]
- Golden outputs: sha256sum -c golden_checksums.txt ✓
Pattern Tiers (Quick Reference)
Tier 1: Low-Hanging Fruit
| Pattern | When | Isomorphism |
|---|---|---|
| N+1 → Batch | Sequential fetches | Same results, fewer round-trips |
| Linear → HashMap | Keyed lookups | O(n)→O(1), order may change |
| Lazy eval | Maybe-unused values | Same final values |
| Memoization | Repeated pure calls | Cached = recomputed |
| Buffer reuse | Alloc per iteration | Zero-copy in loop |
Tier 2: Algorithmic
| Pattern | Change | Check |
|---|---|---|
| Binary search | O(n)→O(log n) | Sorted input |
| Two-pointer | O(n²)→O(n) | Structured input |
| Prefix sums | O(n)→O(1) query | Static data |
| Priority queue | O(n)→O(log n) | Top-k/scheduling |
Tier 3: Data Structures
| Structure | Use Case |
|---|---|
| HashMap | Point lookups |
| BTreeMap | Range queries |
| SmallVec | Usually-small collections |
| Arena | Many allocations, bulk free |
| Bloom filter | Membership pre-filter |
What ships with it
4 files 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.
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.
- 1mo ago First seen · 151 lines · 41 tokens per session scan A 1d1844275501
extreme-software-optimization is a skill published in the GitHub repository compozy/skeeper (89 stars, last pushed 4mo ago), licensed MIT. It adds 41 tokens to every session and 1,217 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to extreme-software-optimization, differing in 0 lines, and is treated as a copy.
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