What is file-loading?

A guide to loading files and other assets into XnaFiddle, a browser-based environment for running XNA examples. It describes embedded files, fetched URLs, drag-and-drop files, and Gist imports, all stored in memory.

Use it when adding asset formats, importing files, supporting drag-and-drop, loading content from a Gist, or exporting projects.

It explains how assets are handled when there is no normal disk or content pipeline. This helps prevent code from assuming that files can be read from a traditional project folder.

How vchelaru/XnaFiddle configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to vchelaru/XnaFiddle. 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/XnaFiddle/main/.claude/skills/file-loading/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/vchelaru/XnaFiddle

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/vchelaru/xnafiddle/file-loading/github.svg)](https://agentmods.dev/skills/vchelaru/xnafiddle/file-loading)

Your own site

<a href="https://agentmods.dev/skills/vchelaru/xnafiddle/file-loading"><img src="https://agentmods.dev/badge/skills/vchelaru/xnafiddle/file-loading/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/vchelaru/xnafiddle/file-loading"><img src="https://agentmods.dev/badge/skills/vchelaru/xnafiddle/file-loading.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,450 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00065	$0.03450
Opus 5.5	$0.00026	$0.01380
Sonnet 5.5	$0.00013	$0.00690
Haiku 4.5	$0.00006	$0.00345

Measured 1mo ago against content hash 0a3c8e1ea53c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

file-loading 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.

.claude/skills/file-loading/SKILL.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

File Loading

XnaFiddle has no disk or traditional content pipeline. All assets live in memory and are loaded through InMemoryContentManager, a custom ContentManager subclass that serves files from a static Dictionary<string, byte[]>.

Four entry paths, one destination

Source	Mechanism	Ends up in	SourceUrl set?
Example assets	Embedded resources in the assembly, loaded by `ExampleGallery.LoadAssets()`	`RegisterContentFile()`	Yes — points to `wwwroot/examples/{ExampleName}/{file}`
URL-fetched assets	`FetchAndAddAssetUrl(url)` via `&assets=` share param or URL input	`RegisterContentFile()`	Yes — the fetched URL
User drag-and-drop	JS `fileDropInterop` -> `OnFileDropped` JSInvokable	`RegisterContentFile()`	No — cannot be re-fetched
Gist import	`LoadFromGistId`: each gist file whose ext is in `SupportedAssetExtensions` is base64-decoded by `DecodeGistAssetAsync` (fetches `raw_url` when `truncated`) and registered via `RegisterGistAsset`	`RegisterContentFile()`	No (issue #82)

All four paths converge on RegisterContentFile(fileName, bytes) in Index.razor.cs, which does two things:

InMemoryContentManager.AddFile(fileName, bytes) — stores data under the original filename AND the extension-stripped name (so Content.Load<Texture2D>("KniIcon") works without knowing the extension)
contentFileCache.register(fileName, base64) via JS interop — registers the file in the JS-side XHR cache so TitleContainer.OpenStream() can resolve it (see below)

Supported formats

Controlled by SupportedAssetExtensions in Index.razor.cs:

.png — loaded as Texture2D via Texture2D.FromStream()
.wav — loaded as SoundEffect via SoundEffect.FromStream()
.fnt — BMFont text format; stored as raw bytes. The UI parses page lines to show which texture files the font references (so users know what companion .png files to also drop)
.ttf — TrueType font; stored as raw bytes for FontStashSharp
.ember — stored as raw bytes
.tmx .tsx .world .ldtk .ogmo .json .txt .xml — text/data formats (tilemap & level-editor files plus generic data); stored as raw bytes and read by user code via TitleContainer.OpenStream (no Load<T> branch)

Read the full file on GitHub · 131 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.

1mo ago Changed 0a3c8e1ea53c
1mo ago First seen · 131 lines · 65 tokens per session scan A 248b790b27be

Subscribe to this mod's changes

file-loading is a skill published in the GitHub repository vchelaru/XnaFiddle (14 stars, last pushed today), licensed MIT. It adds 65 tokens to every session and 3,450 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-09-04.

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XnaFiddle: Skill for Claude Code