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 skills add ouzlifaneyassine1-dot/onyx-engine --skill diagnosing-perf-regressionsgit clone --depth 1 https://github.com/ouzlifaneyassine1-dot/onyx-engineWrote 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/ouzlifaneyassine1-dot/onyx-engine/diagnosing-perf-regressions)<a href="https://agentmods.dev/skills/ouzlifaneyassine1-dot/onyx-engine/diagnosing-perf-regressions"><img src="https://agentmods.dev/badge/skills/ouzlifaneyassine1-dot/onyx-engine/diagnosing-perf-regressions/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/ouzlifaneyassine1-dot/onyx-engine/diagnosing-perf-regressions"><img src="https://agentmods.dev/badge/skills/ouzlifaneyassine1-dot/onyx-engine/diagnosing-perf-regressions.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 | $0.00058 | $0.02356 |
| Opus 5 | $0.00029 | $0.01178 |
| Sonnet 5 | $0.00012 | $0.00471 |
| Haiku 4.5 | $0.00006 | $0.00236 |
Grade A, and why
diagnosing-perf-regressions 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
86% identical to diagnosing-perf-regressions — 87 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 — 191 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Diagnosing Performance Regressions
Overview
There is a difference between "this game is slow" and "this game got slow." This skill is for the second one.
Core principle: A regression has a cause. The cause is a specific change. Bisect to find the change, then root-cause from there.
This skill is not general performance tuning. If the game has always run at 30fps and you want to push it to 60, that is onyx:tune-performance (the domain skill for budget-driven optimization). This skill is the diagnostic — what broke, where, when.
When To Use
- "It used to run at 60fps, now it's at 30."
- "Load time was 3s yesterday, now it's 15s."
- "Frame stutters started after I added X."
- "Build went from buttery to choppy and I don't know why."
When NOT To Use
- "The game has always been slow, help me speed it up." →
onyx:tune-performance. - "I want to know if my game is fast enough to ship." →
onyx:tune-performance. - "The game crashes." →
onyx:debug.
The Iron Law
NO PERF FIX WITHOUT A KNOWN-GOOD vs KNOWN-BAD MEASUREMENT
You cannot fix a regression you have not measured. Eyeballing "feels laggy" is not a measurement. Get a number for the good state and a number for the bad state before touching code.
The Loop
Measure now → Find last good → Bisect changes → Match to a cliff → A/B fix → Re-measure
1. Measure now
onyx_play (on the scene that's slow)
── wait 5-10 seconds of normal play ──
onyx_get_diagnostics
onyx_get_console
onyx_stop
What to capture:
| Metric | Source | Why |
|---|---|---|
| Avg FPS / frame time | onyx_get_diagnostics or in-game perf monitor |
Headline number |
| Spike pattern | onyx_get_console if user has frame-time prints, else in-game monitor |
Steady 30 vs intermittent stutters → different causes |
| Scene complexity | onyx_get_scene_tree (root counts) |
Establishes baseline for instance/body count cliffs |
Write the bad-state number down. "Scene Level3 runs at 31fps avg, drops to 12fps when 5+ enemies are on screen."
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 · 191 lines · 58 tokens per session scan A ab4eb397a025
diagnosing-perf-regressions is a skill published in the GitHub repository ouzlifaneyassine1-dot/onyx-engine (0 stars, last pushed 3mo ago), licensed MIT. It adds 58 tokens to every session and 2,356 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 86% identical to diagnosing-perf-regressions, differing in 87 lines, and is treated as a copy.
Other skills, from other repositories
minecraft-debug-mcp
Operate and debug the live Minecraft bot through its built-in MCP REPL server. Use when work requires starting the bot with pnpm dev, connecting to the local MCP endpoint, inspecting cognitive state/logs/history, injecting synthetic chat/events, or running targeted REPL code against the running brain during…
graphics-api-hooking
Analyze Direct3D/DXGI, OpenGL, and Vulkan rendering, presentation, composition, and capture evidence. Use to distinguish API samples, PresentMon event metrics, Tracy instrumentation, compatibility translation, frame images, and validation diagnostics; review swap chains, overlays, resource lifetime, and…
console-get-logs
Retrieve Unity Editor logs from the MCP plugin's LogCollector, optionally filtered by log type or time window. Useful for debugging and monitoring Editor activity.
editor-application-get-state
Return the current state of UnityEditor.EditorApplication — playmode, paused state, compilation state, and related flags.
console-clear-logs
Clear the MCP log cache (used by 'console-get-logs') and the Unity Editor Console window. Useful for isolating logs to a specific action by clearing the slate first.
profiler-start
Enable Unity's runtime profiler and open the Profiler window. Idempotent: calling when already enabled returns the current enabled state without error.