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.
git clone --depth 1 https://github.com/VuDZ/RoslynMcpServerWrote 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/rules/vudz/roslynmcpserver/roslyn-mcp-build-sdk)<a href="https://agentmods.dev/rules/vudz/roslynmcpserver/roslyn-mcp-build-sdk"><img src="https://agentmods.dev/badge/rules/vudz/roslynmcpserver/roslyn-mcp-build-sdk/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/rules/vudz/roslynmcpserver/roslyn-mcp-build-sdk"><img src="https://agentmods.dev/badge/rules/vudz/roslynmcpserver/roslyn-mcp-build-sdk.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 | $0.00000 | $0.01203 |
| Opus 5.5 | $0.00000 | $0.00481 |
| Sonnet 5.5 | $0.00000 | $0.00241 |
| Haiku 4.5 | $0.00000 | $0.00120 |
Grade A, and why
roslyn-mcp-build-sdk 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.
How it starts
The opening of the file, as written. The whole thing — 38 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Build / SDK / DotNet CLI
Bitness
MCP process is 64-bit. x86 MSBuild/SDK → BadImageFormatException. Use 64-bit dotnet (DotNetHostResolver). MsBuildBootstrapper.Register() before workspace use.
global.json pinning
DotNetSdkEnvironment / GlobalJsonSdkReader: pin via MSBUILD_EXE_PATH, MSBuildSDKsPath, DOTNET_MSBUILD_SDK_RESOLVER_SDKS_*, DOTNET_ROOT, inherit full process env. Working directory = nearest ancestor with global.json when possible.
Without a resolved pin, strip inherited MSBuildSDKsPath / MSBUILD_EXE_PATH / resolver vars (MSBuildLocator and Cursor/VS often leave SDK 9.x overrides → NETSDK1045 on net10).
Run metadata includes inherited overrides, strip/pin SDK env action, and SDK version inferred from MSBuild/NETSDK log paths.
run_dotnet_build (DotNetBuildProbe)
Escalate when diagnostics missing: build -v:minimal → restore → build -v:normal. Parse MSBuild path(line,col): error|warning and NuGet NU#### / GHSA. Surface MCP_MSBUILD_SDK_MISMATCH if log SDK ≠ pin. Deduplicate repeated NU lines.
Optional tool arg configuration → -c on build steps only (multi-config .slnx: Sit-Debug, Dit-Debug, …). Omit to inherit load_workspace configuration. Optional platform → -p:Platform= (same inherit).
Default noIncremental=true → --no-incremental on every build step (agent verification must not trust MSBuild up-to-date). Effective exit = last dotnet build step — never let restore exit 0 mask a failed build with no rebuild. Report Configuration / NoIncremental in metadata.
While a step lives, run_dotnet_build emits MCP notifications/progress heartbeats (step label, elapsed, previous exit; no stdout) through DotNetCliRunner/DotNetBuildProbe; the SDK-injected IProgress<ProgressNotificationValue> parameter is schema-excluded (McpToolHelpFormatter.IsMcpBoundParameter). UX only — never claim it raises the host tools/call timeout.
Tests (VstestOutputParser / TestTools)
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 1201963932de
- 1mo ago Changed · +1 lines dc0266a1f767
- 1mo ago Changed f2068da6a621
- 1mo ago Changed · +1 lines 2ed61021b4b1
- 1mo ago First seen · 36 lines · 0 tokens per session scan A abc0d4e51323
roslyn-mcp-build-sdk is a cursor rule published in the GitHub repository VuDZ/RoslynMcpServer (8 stars, last pushed today), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,203 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 2026-09-14.
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