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.
curl -O https://raw.githubusercontent.com/vchelaru/XnaFiddle/main/.claude/skills/intellisense/SKILL.mdgit clone --depth 1 https://github.com/vchelaru/XnaFiddleWrote 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/vchelaru/xnafiddle/intellisense)<a href="https://agentmods.dev/skills/vchelaru/xnafiddle/intellisense"><img src="https://agentmods.dev/badge/skills/vchelaru/xnafiddle/intellisense/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/vchelaru/xnafiddle/intellisense"><img src="https://agentmods.dev/badge/skills/vchelaru/xnafiddle/intellisense.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 | $0.00067 | $0.03583 |
| Opus 5 | $0.00034 | $0.01792 |
| Sonnet 5 | $0.00013 | $0.00717 |
| Haiku 4.5 | $0.00007 | $0.00358 |
Grade A, and why
intellisense 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 4d 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.
How it starts
The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Architecture
One IntellisenseService singleton (DI, app lifetime) holds an AdhocWorkspace + a single User.cs document. Every JSInvokable call swaps document text via Solution.WithDocumentText(_documentId, ...) + _workspace.TryApplyChanges(...), then drives Roslyn:
- Completion:
CompletionService.GetService(document).GetCompletionsAsync(...) - Hover:
SemanticModel.GetDeclaredSymbol/GetSymbolInfo+ customSymbolDisplayFormat - Signature help: walk syntax tree for enclosing
InvocationExpressionSyntax, resolve viaSemanticModel.GetSymbolInfo, format manually - Live diagnostics:
Project.GetCompilationAsync().GetDiagnostics()
SignatureHelpService and QuickInfoService are internal in Roslyn 4.14, so hover and sig help bypass them and drive the SemanticModel directly. Metadata references are pulled from CompilationService.GetMetadataReferencesAsync so the completion surface exactly matches the compile surface.
Key files
| File | Purpose |
|---|---|
XnaFiddle.BlazorGL/IntellisenseService.cs |
Singleton; workspace, CTS-per-op, all four JSInvokables |
XnaFiddle.BlazorGL/Intellisense/XmlDocFormatter.cs |
XML doc -> Monaco-flavor markdown |
XnaFiddle.BlazorGL/Intellisense/SignatureFormatter.cs |
Builds label + per-param offset ranges |
XnaFiddle.BlazorGL/Intellisense/ActiveParameterLocator.cs |
Top-level-comma counter for active param |
XnaFiddle.BlazorGL/wwwroot/js/monaco-interop.js |
Monaco providers, debounce, cache, marker layers |
XnaFiddle.BlazorGL/Pages/Index.razor[.cs] |
DI wiring, warmup kickoff, loading indicator |
XnaFiddle.Tests/Intellisense/*Tests.cs |
Tests for the pure-logic helpers only |
WASM single-thread constraint (critical)
All Roslyn work runs on the one WASM thread; a long call blocks typing. Three layered mitigations:
- JS-side tiered debounce in
_registerCompletions:.(member access): 50ms- Ctrl+Space on empty word: 0ms (fire immediately)
- Typing with word length >= 3: 400ms
- Typing with word length < 3: skipped entirely (returns
{suggestions: []})
- Word-start cache (
_completionCache, keyed by{sourcePrefix, wordStartOffset}): while the user types inside the same word, Monaco filters client-side against the cached result and no .NET call happens. - Per-op
CancellationTokenSourceinIntellisenseService(_currentCompletionCts,_currentSignatureHelpCts,_currentHoverCts,_currentDiagnosticsCts): a new request on the same channel cancels the prior one mid-flight. Separate CTS per op means sig help and completion don't cancel each other.
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.
- 4d ago First seen · 132 lines · 67 tokens per session scan A 3505fda2cdbe
intellisense is a skill published in the GitHub repository vchelaru/XnaFiddle (13 stars, last pushed 3d ago), licensed MIT. It adds 67 tokens to every session and 3,583 once invoked, about $0.0003 per session on Opus 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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