What is roslyn-mcp-structural-tests?

A testing rule for C# projects that says source text alone must not be used to claim how production code is structured or behaves. C# is a programming language, and structural analysis checks code shape rather than just matching words.

It is for reviewing tests that inspect C# source, deciding when exact text checks are acceptable, and replacing unreliable text matching with behavioural or structural checks.

Text searches can give false confidence about method calls, locks, or symbol counts. The rule requires running code to check behaviour and using dedicated source-analysis tools to check structure.

roslyn-mcp-structural-tests — Cursor rule for Cursor by VuDZ

Install

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.

Clone the repo

git clone --depth 1 https://github.com/VuDZ/RoslynMcpServer

Made for: Cursor.

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/rules/vudz/roslynmcpserver/roslyn-mcp-structural-tests/github.svg)](https://agentmods.dev/rules/vudz/roslynmcpserver/roslyn-mcp-structural-tests)

Your own site

<a href="https://agentmods.dev/rules/vudz/roslynmcpserver/roslyn-mcp-structural-tests"><img src="https://agentmods.dev/badge/rules/vudz/roslynmcpserver/roslyn-mcp-structural-tests/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/rules/vudz/roslynmcpserver/roslyn-mcp-structural-tests"><img src="https://agentmods.dev/badge/rules/vudz/roslynmcpserver/roslyn-mcp-structural-tests.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 184 This file is loaded in full into every session.

When invoked 184 The same file — it is already loaded in full.

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	$0.00184	$0.00184
Opus 5.5	$0.00074	$0.00074
Sonnet 5.5	$0.00037	$0.00037
Haiku 4.5	$0.00018	$0.00018

Measured 17d ago against content hash 2dd5f44cf15c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

roslyn-mcp-structural-tests 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 17d 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.

.cursor/rules/roslyn-mcp-structural-tests.mdc · 15 lines

What it actually says

Structural tests

Do not infer the structure or semantics of production C# from the text of a source file. Do not conclude that a method calls a method, that a lock is taken, or that a symbol occurs once from IndexOf, Contains, Regex, a slice between declarations, or a window around a substring. A green test does not make a text slice a structural check.

Check behavior by executing it. Check the shape of the code through SourceSetAnalysis and the helpers next to it in RoslynMcpServer.Tests/SourceStructure/.

Exact text is allowed when the contract is the text itself: a message, CLI output, a .csproj, markdown, or a generated file.

Canon: docs/code-style.md, section "Tests that inspect production code".

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.

17d ago First seen · 15 lines · 184 tokens per session scan A 2dd5f44cf15c

Subscribe to this mod's changes

roslyn-mcp-structural-tests is a cursor rule published in the GitHub repository VuDZ/RoslynMcpServer (8 stars, last pushed 8d ago), licensed MIT. It adds 184 tokens to every session, about $0.0007 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 2026-09-29.

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