FlatRedBall2: Skill for Claude Code

.claude/skills/performance/SKILL.md

performance is a skill for Claude Code from vchelaru/FlatRedBall2. It costs 0 tokens per session (531 once invoked), scanned A, original, MIT.

A performance monitor for a game that records frame rate, time spent in game phases, and collision costs over recent frames. It is disabled until explicitly enabled and can produce a text report.

In plain words
What is it for?
Use it to investigate game slowdowns, inspect frame-time data, and find costly collision relationships.
Why use it?
It helps identify whether slow gameplay comes from low frame rate, a particular processing phase, or expensive collision checks.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is vchelaru/FlatRedBall2's own configuration. It tells Claude Code how to work on FlatRedBall2 itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything FlatRedBall2 configures →

Reuse

Borrowing it

Nothing to install: this file belongs to vchelaru/FlatRedBall2. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/vchelaru/FlatRedBall2/main/.claude/skills/performance/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/vchelaru/FlatRedBall2

Made for: Claude Code.

Wrote 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.

agentmods badge for performance

README.md
[![agentmods](https://agentmods.dev/badge/skills/vchelaru/flatredball2/performance.svg)](https://agentmods.dev/skills/vchelaru/flatredball2/performance)
Your own site
<a href="https://agentmods.dev/skills/vchelaru/flatredball2/performance"><img src="https://agentmods.dev/badge/skills/vchelaru/flatredball2/performance.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 531 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00000 $0.00531
Opus 5 $0.00000 $0.00266
Sonnet 5 $0.00000 $0.00106
Haiku 4.5 $0.00000 $0.00053

Measured yesterday against content hash 8635e2d9d5c2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

performance 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 yesterday.

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.

.claude/skills/performance/SKILL.md · 35 lines

How it starts

The opening of the file, as written. The whole thing — 35 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Performance Monitoring

FlatRedBallService.Default.Performance (a PerformanceMonitor, src/Diagnostics/PerformanceMonitor.cs) tracks rolling FPS, per-phase frame timing, and a per-collision-relationship severity breakdown over a 120-frame window.

Off by default — set IsEnabled = true before it records anything; until then every stat reads zero/empty.

FlatRedBallService.Default.Performance.IsEnabled = true;

// later, e.g. every N frames from Screen.CustomActivity:
var perf = FlatRedBallService.Default.Performance;
Console.WriteLine(perf.GenerateReport());   // FPS + phase timing + collision severity, as a string
var fps = perf.Fps;                         // .Current / .Average / .Min / .Max
var worst = perf.GetCollisionReport();      // most expensive first; each row carries a PartitionStatus

GenerateReport() only builds a string — it does no I/O itself, so printing/logging/writing it is on the caller.

Timer resolution (web)

GenerateReport() opens with a Platform: line and the measured clock step (TimerResolutionMs, probed once via ProfileClock.MeasureResolutionMs).

Landmine: browsers coarsen their clock as a Spectre mitigation — ~1ms on Firefox/Safari, ~0.1ms on Chrome — and Stopwatch.Frequency does not reflect it. Whole-pass totals stay accurate (start/end errors cancel), but any per-phase number smaller than one step reads as 0 or one full step and nothing between. The report warns automatically above 0.5ms.

Set PlatformLabel from the host — the engine targets net10.0 and cannot read navigator.userAgent itself.

Every row in the collision report carries a PartitionStatus. Unpartitioned is the only value worth acting on, and the fix is to set the same Factory<T>.PartitionAxis on both sides of the relationship. NotApplicable means one side is not a factory, such as a TileShapes, a single entity, or a plain List<T>, so no axis setting would change it. See the collision-relationships skill.

See src/Diagnostics/FrameProfile.cs for the underlying per-frame timing struct.

Read the full file on GitHub · 35 lines

Changes

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.

  1. yesterday First seen · 35 lines · 0 tokens per session scan A 8635e2d9d5c2

Subscribe to this mod's changes

performance is a skill published in the GitHub repository vchelaru/FlatRedBall2 (14 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 531 tokens. 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 2026-09-04.