Public record
Software health reportschema 0.34.0 · metrics 2.10.0 · 2026-09-09 08:31 UTC

microsoft / vs-mef

Managed Extensibility Framework (MEF) implementation used by Visual Studio

C#MIT★ 464 stars⑂ 93 forkssince Apr 2017View on GitHub ↗
KindCommand-line toolhow this is determined
#mef#visual-studio#extensibility#extensibility-engine

microsoft/vs-mef holds a health index of 93 out of 100, placing it in the Exceptional band. It scores highest on Engineering Quality (84/100) and lowest on Sustainability & Governance (72/100). It was last updated today. A single contributor accounts for most of its recent work.

93
overall / 100
Exceptional

Software health index

Metrics are grouped into weighted categories on one standardized 1–100 scale. Overall starts as their weighted mean, calibrated against the distribution of the public record so bands carry percentile meaning; when public evidence triggers the High-Risk Jurisdiction Policy, the rating is adjusted and receives an At Risk ceiling of 34.

93
Exceptional93-100The record's top tier (≈ top 5%); essentially all checked criteria met
Excellent80-92Strong across the board; minor gaps
Good65-79Healthy; gaps are limited and manageable
Moderate50-64Acceptable with notable gaps; review recommended
Weak35-49Material weaknesses across several areas
At Risk20-34Significant weaknesses; adoption warrants caution
Critical1-19Severe problems (abandoned, single-maintainer, no hygiene)
VitalityCommunity &AdoptionSustainability &GovernanceEngineeringQualitySecurityAI Readiness

Score profile

Each axis is a category. The shape matters more than the average — a healthy subject fills the whole shape, while a spike-and-crater profile means strength in one dimension is masking risk in another.

The weighted overall 79 is calibrated to 93 on the published index scale (record calibration 2026-08-02).

Ownership

MicrosoftOrganization · verified domain
129,348 followers8,299 public repossince Dec 2013

This repository is backed by an organization — shared, accountable stewardship that can outlive any single maintainer.

Package ecosystems

RegistryPackageVersionDownloads / moVersionsLast publishTags
NuGetMicrosoft.VisualStudio.Composition.Analyzers17.13.41-19482 days agomefanalyzers

Metrics by category

Vitality

Is the project alive — is code being written and are releases shipping?

81Excellent · 21% of overall

Development activity

100Exceptional
How it's scored
36/36Push recency — last push 0 days ago
36/36Commit cadence — 52/52 weeks with commits
18/18Commit volume — 613 commits in the last year
10/10OpenSSF Scorecard: Maintained — 30 commit(s) and 5 issue activity found in the last 90 days -- score normalized to 10
Inputs used
commits_last_year613
human_commit_share0.81
days_since_last_push0
active_weeks_last_year52

Release discipline

52Moderate
How it's scored
27/27Ships releases — 16 releases published
0/36Release recency — latest release 869 days ago
19.8/27Release cadence — a release every ~87.7 days
0/10OpenSSF Scorecard: Signed-Releases — no data
Inputs used
releases_count16
latest_release_tagv17.10.8-preview
releases_from_tagsno
days_since_latest_release869
mean_days_between_releases87.7
Excluded from scoring (no data or not applicable): OpenSSF Scorecard: Signed-Releases. Remaining weights renormalized.

Community & Adoption

Does the project have users, downloads, attention, and a welcoming setup for contributors?

78Good · 17% of overall

Popularity & adoption

67Good
How it's scored
43.2/60Stars — 464 stars
16.4/25Forks — 93 forks
7.8/15Watchers — 26 watchers
Inputs used
forks93
stars464
watchers26
growth_stateunverified
growth_factor_pct100
growth_unverified_reasonno_history

Community health

85Excellent
How it's scored
22.5/22.5README
22.5/22.5License — recognized license (MIT)
18/18CONTRIBUTING guide
13.5/13.5Code of conduct
0/7.2Issue template
0/6.3PR template
Inputs used
has_readmeyes
has_licenseyes
readme_badges5
has_contributingyes
has_issue_templateno
has_code_of_conductyes
readme_badge_servicescodecov.io, dev.azure.com, shields.io
has_pull_request_templateno

Ecosystem adoption (downloads)

84Excellent
How it's scored
67.1/80Total downloads — 2,855,900 downloads all-time across nuget
0/20Registry dependents — not reported by this ecosystem
Inputs used
packagesMicrosoft.VisualStudio.Composition.Analyzers
dependents—
ecosystemsnuget
total_downloads2,855,900
monthly_downloads—
unverified_packages_excluded—
Excluded from scoring (no data or not applicable): Registry dependents. Remaining weights renormalized.

Sustainability & Governance

Will the project survive its people — bus factor, responsiveness, who backs it, and package upkeep?

72Good · 23% of overall

Maintainer resilience (bus factor)

34At Risk
How it's scored
9/54Bus factor — 1 contributor(s) cover half of all commits
1.4/22.5Commit distribution — top contributor authored 94% of commits
13.5/13.5Contributor breadth — 54 contributors
10/10OpenSSF Scorecard: Contributors — project has 14 contributing companies or organizations
Inputs used
bus_factor1
contributors_sampled54
top_contributor_share0.938

Issue & PR responsiveness

84Excellent
How it's scored
39/42Issue resolution — 93% of issues closed
18.9/30PR acceptance — 426/677 decided PRs merged
0/13Newcomer PR acceptance — no first-time contributor's PR decided in 30d
15/15OpenSSF Scorecard: Code-Review — all changesets reviewed
Inputs used
merged_prs426
open_issues7
closed_issues90
prs_merged_7d5
prs_decided_7d5
prs_merged_30d10
prs_decided_30d10
issue_closed_ratio0.928
closed_unmerged_prs251
first_time_authors_30d0
first_time_prs_merged_30d0
first_time_prs_decided_30d0
Excluded from scoring (no data or not applicable): Newcomer PR acceptance. Remaining weights renormalized.

Ownership & stewardship

100Exceptional
How it's scored
30/30Ownership backing — organization-owned
20/20Verified domain
25/25Owner reach — 129,348 followers of microsoft
25/25Track record — 8,299 public repos, account ~12 yr old
Inputs used
followers129,348
owner_typeOrganization
is_verifiedyes
owner_loginmicrosoft
public_repos8,299
account_age_days4,655

Package maintenance

79Good
How it's scored
25/25Published & resolvable — 1 package(s) on nuget
14/35Publish recency — latest publish 482 days ago
20/20Version history — 19 published versions
20/20Not deprecated — active, not deprecated or yanked
Inputs used
packagesMicrosoft.VisualStudio.Composition.Analyzers
ecosystemsnuget
any_deprecatedno
min_days_since_publish482

Engineering Quality

Are baseline engineering and documentation practices in place?

84Excellent · 19% of overall

Engineering practices

74Good
How it's scored
24/24CI workflows — 4 workflow(s)
24/24Tests present
0/16Linter config
0/9.6Pre-commit hooks
6.4/6.4.editorconfig
20/20OpenSSF Scorecard: CI-Tests — 13 out of 13 merged PRs checked by a CI test -- score normalized to 10
Inputs used
has_ciyes
has_testsyes
has_editorconfigyes
has_linter_configno
has_precommit_configno

Documentation

100Exceptional
How it's scored
30/30README
25/25Documentation directory
15/15Documentation / homepage site — https://microsoft.github.io/vs-mef/
10/10Repository description
10/10Topics — 4 topics
10/10Wiki
Inputs used
topicsmef, visual-studio, extensibility, extensibility-engine
has_wikiyes
homepagehttps://microsoft.github.io/vs-mef/
docs_sitehttps://microsoft.github.io/vs-mef/
has_readmeyes
has_docs_diryes
has_descriptionyes

Security

Are visible security and supply-chain practices strong, without unresolved high-risk jurisdiction exposure?

80Excellent · 16% of overall

Security posture

80Excellent
How it's scored
7.5/7.5Binary-Artifacts — no binaries found in the repo
3.8/7.5Branch-Protection — branch protection is not maximal on development and all release branches
2.5/2.5CI-Tests — 13 out of 13 merged PRs checked by a CI test -- score normalized to 10
0/2.5CII-Best-Practices — no effort to earn an OpenSSF best practices badge detected
7.5/7.5Code-Review — all changesets reviewed
2.5/2.5Contributors — project has 14 contributing companies or organizations
10/10Dangerous-Workflow — no dangerous workflow patterns detected
7.5/7.5Dependency-Update-Tool — update tool detected
0/5Fuzzing — project is not fuzzed
2.5/2.5License — license file detected
7.5/7.5Maintained — 30 commit(s) and 5 issue activity found in the last 90 days -- score normalized to 10
0/5Packaging — no data
5/5Pinned-Dependencies — all dependencies are pinned
5/5SAST — SAST tool is run on all commits
5/5Security-Policy — security policy file detected
0/7.5Signed-Releases — no data
0/7.5Token-Permissions — detected GitHub workflow tokens with excessive permissions
7.5/7.5Vulnerabilities — 0 existing vulnerabilities detected
Inputs used
sourceopenssf_scorecard
checks_evaluated16
scorecard_versionv5.5.0
checks_inconclusive2
scorecard_aggregate8
Excluded from scoring (no data or not applicable): Packaging, Signed-Releases. Remaining weights renormalized.

AI Readiness

How well is the repo equipped to be developed and maintained with AI coding agents? Carries a deliberately small weight (4%): agent tooling is a real maintenance signal, but a repository with none can still reach 100/100.

83Excellent · 4% of overall

Agent context & guidance

79Good
How it's scored
45/45Agent instructions — AGENTS.md
0/15Machine-readable docs (llms.txt)
33.6/40Legible commit history — 51 of 81 human commits state their intent (structured subject or explanatory body)
Inputs used
has_llms_txtno
llms_txt_url—
legible_history_share0.63
agent_instruction_filesAGENTS.md
agent_instruction_max_bytes4,613

Verify loop (build / test / typecheck)

74Good
How it's scored
12.6/18One-command bootstrap — samples/Samples.csproj, src/Microsoft.VisualStudio.Composition.Analyzers.CSharp/Microsoft.VisualStudio.Composition.Analyzers.CSharp.csproj, src/Microsoft.VisualStudio.Composition.Analyzers.CodeFixes/Microsoft.VisualStudio.Composition.Analyzers.CodeFixes.csproj (toolchain convention, no task runner)
22/22Automated tests
0/11Lint / format config
11/11Static type checking — C# (statically typed)
0/10Reproducible environment
10/10Demonstrated agent practice — 28 of the last 100 commits agent-authored or agent-credited
8/8Automated maintenance — 19 of the last 100 commits are automated dependency updates
10/10OpenSSF Scorecard: Pinned-Dependencies — all dependencies are pinned
Inputs used
has_nixno
has_testsyes
lockfiles—
has_dockerfileno
typed_languageyes
bootstrap_files—
has_devcontainerno
has_linter_configno
typecheck_configs—
agent_commit_share0.28
toolchain_manifestssamples/Samples.csproj, src/Microsoft.VisualStudio.Composition.Analyzers.CSharp/Microsoft.VisualStudio.Composition.Analyzers.CSharp.csproj, src/Microsoft.VisualStudio.Composition.Analyzers.CodeFixes/Microsoft.VisualStudio.Composition.Analyzers.CodeFixes.csproj, src/Microsoft.VisualStudio.Composition.Analyzers.VB/Microsoft.VisualStudio.Composition.Analyzers.VB.csproj, src/Microsoft.VisualStudio.Composition.Analyzers/Microsoft.VisualStudio.Composition.Analyzers.csproj, src/Microsoft.VisualStudio.Composition.AppHost/Microsoft.VisualStudio.Composition.AppHost.csproj, src/Microsoft.VisualStudio.Composition.VSMefx/Microsoft.VisualStudio.Composition.VSMefx.csproj, src/Microsoft.VisualStudio.Composition/Microsoft.VisualStudio.Composition.csproj, test/Microsoft.VisualStudio.Composition.Analyzers.Tests/Microsoft.VisualStudio.Composition.Analyzers.Tests.csproj, test/Microsoft.VisualStudio.Composition.AppDomainTests/Microsoft.VisualStudio.Composition.AppDomainTests.csproj, test/Microsoft.VisualStudio.Composition.AppDomainTests2/Microsoft.VisualStudio.Composition.AppDomainTests2.csproj, test/Microsoft.VisualStudio.Composition.AssemblyDiscoveryTests/Microsoft.VisualStudio.Composition.AssemblyDiscoveryTests.csproj, test/Microsoft.VisualStudio.Composition.AssemblyDiscoveryTests2/Microsoft.VisualStudio.Composition.AssemblyDiscoveryTests2.csproj, test/Microsoft.VisualStudio.Composition.Benchmarks/Microsoft.VisualStudio.Composition.Benchmarks.csproj, test/Microsoft.VisualStudio.Composition.BrokenAssemblyTests/Microsoft.VisualStudio.Composition.BrokenAssemblyTests.csproj, test/Microsoft.VisualStudio.Composition.EmbeddedTypeReceiver/Microsoft.VisualStudio.Composition.EmbeddedTypeReceiver.csproj, test/Microsoft.VisualStudio.Composition.MissingAssemblyTests/Microsoft.VisualStudio.Composition.MissingAssemblyTests.csproj, test/Microsoft.VisualStudio.Composition.NonEmbeddingTypeReceiver/Microsoft.VisualStudio.Composition.NonEmbeddingTypeReceiver.csproj, test/Microsoft.VisualStudio.Composition.TestEmbeddableTypes/Microsoft.VisualStudio.Composition.TestEmbeddableTypes.csproj, test/Microsoft.VisualStudio.Composition.Tests/Microsoft.VisualStudio.Composition.Tests.csproj, test/VS.Mefx.Tests/TestFiles/BasicScripts/ExtendedOperations/ExtendedOperations.csproj, test/VS.Mefx.Tests/TestFiles/BasicScripts/MefCalculator/MefCalculator.csproj, test/VS.Mefx.Tests/TestFiles/MatchingScripts/CarOne/CarOne.csproj, test/VS.Mefx.Tests/TestFiles/MatchingScripts/CarTwo/CarTwo.csproj, test/VS.Mefx.Tests/TestFiles/MatchingScripts/Garage/Garage.csproj, test/VS.Mefx.Tests/TestFiles/MatchingScripts/User/User.csproj, test/VS.Mefx.Tests/VS.Mefx.Tests.csproj
dependency_bot_commit_share0.19

Code legibility for models

100Exceptional
How it's scored
45/45Type-checkable code — C# (statically typed)
54.7/55Manageable file sizes — 2/337 source files over 60KB
Inputs used
primary_languageC#
largest_source_bytes99,823
source_files_sampled337
oversized_source_files2

Machine-readable interfaces

100Exceptional
How it's scored
0/40API schema (OpenAPI/GraphQL/proto) — not applicable to this kind of software
20/20MCP server
40/40Runnable examples — samples
Inputs used
example_dirssamples
has_mcp_signalyes
api_schema_files—
interfaces_expected_of—
Excluded from scoring (no data or not applicable): API schema (OpenAPI/GraphQL/proto). Remaining weights renormalized.

Key facts

464GitHub stars
54contributors
613commits, last 12 months
0days since last push
16releases
1bus factor
7open issues
NuGetpackage ecosystems

Data collection warnings

  • Star history unavailable: GitHub GraphQL error: Resource not accessible by personal access token
  • Could not fetch nuget package 'Microsoft.VisualStudio.Composition.Analyzers.Only' from its registry
  • No resolved dependencies carried a version and a supported ecosystem

More detail

Star and fork history 0 ★ / 93 ⇿
0Stars
93Forks
16Releases

When each star and fork was added, collected from GitHub and bucketed by day. Cumulative growth sits directly above the daily additions it is made of, so the two read against each other: steady organic accretion looks nothing like an abrupt, short-lived burst. Where that difference is measurable, it is reported as growth authenticity.

0204060801009252017-042021-122026-07
Major 0Minor 0Patch 13

Each point covers 9 days.

OpenSSF Scorecard 8.0 / 10
8.0aggregate

Independent, tool-agnostic security assessment from the open-source OpenSSF Scorecard. Each check rewards a security practice, not a specific vendor's tool. Checks Scorecard could not determine are marked n/a and excluded from the security score (never counted as zero).Scorecard v5.5.0 · 2026-09-09 08:31 UTC

10Binary-Artifactsno binaries found in the repo
5Branch-Protectionbranch protection is not maximal on development and all release branches
10CI-Tests13 out of 13 merged PRs checked by a CI test -- score normalized to 10
0CII-Best-Practicesno effort to earn an OpenSSF best practices badge detected
10Code-Reviewall changesets reviewed
10Contributorsproject has 14 contributing companies or organizations
10Dangerous-Workflowno dangerous workflow patterns detected
10Dependency-Update-Toolupdate tool detected
0Fuzzingproject is not fuzzed
10Licenselicense file detected
10Maintained30 commit(s) and 5 issue activity found in the last 90 days -- score normalized to 10
n/aPackagingpackaging workflow not detected
10Pinned-Dependenciesall dependencies are pinned
10SASTSAST tool is run on all commits
10Security-Policysecurity policy file detected
n/aSigned-Releasesno releases found
0Token-Permissionsdetected GitHub workflow tokens with excessive permissions
10Vulnerabilities0 existing vulnerabilities detected
Direct dependencies 18
RegistryPackageVersion constraintManifest
NuGetMicrosoft.CodeAnalysis.CSharp—src/Microsoft.VisualStudio.Composition.Analyzers.CSharp/Microsoft.VisualStudio.Composition.Analyzers.CSharp.csproj
NuGetMicrosoft.CodeAnalysis.CSharp.Workspaces—src/Microsoft.VisualStudio.Composition.Analyzers.CodeFixes/Microsoft.VisualStudio.Composition.Analyzers.CodeFixes.csproj
NuGetMicrosoft.CodeAnalysis.VisualBasic—src/Microsoft.VisualStudio.Composition.Analyzers.VB/Microsoft.VisualStudio.Composition.Analyzers.VB.csproj
NuGetMicrosoft.CodeAnalysis.Common—src/Microsoft.VisualStudio.Composition.Analyzers/Microsoft.VisualStudio.Composition.Analyzers.csproj
NuGetMicrosoft.CodeAnalysis.Analyzers—src/Microsoft.VisualStudio.Composition.Analyzers/Microsoft.VisualStudio.Composition.Analyzers.csproj
NuGetNerdbank.MSBuildExtension—src/Microsoft.VisualStudio.Composition.AppHost/Microsoft.VisualStudio.Composition.AppHost.csproj
NuGetOpenSoftware.DgmlBuilder—src/Microsoft.VisualStudio.Composition.VSMefx/Microsoft.VisualStudio.Composition.VSMefx.csproj
NuGetSystem.CommandLine.DragonFruit—src/Microsoft.VisualStudio.Composition.VSMefx/Microsoft.VisualStudio.Composition.VSMefx.csproj
NuGetNerdbank.NetStandardBridge—src/Microsoft.VisualStudio.Composition.VSMefx/Microsoft.VisualStudio.Composition.VSMefx.csproj
NuGetNerdbank.MessagePack—src/Microsoft.VisualStudio.Composition/Microsoft.VisualStudio.Composition.csproj
NuGetMicrosoft.VisualStudio.Threading.Analyzers—src/Microsoft.VisualStudio.Composition/Microsoft.VisualStudio.Composition.csproj
NuGetMicrosoft.VisualStudio.Threading.Only—src/Microsoft.VisualStudio.Composition/Microsoft.VisualStudio.Composition.csproj
NuGetMicrosoft.VisualStudio.Validation—src/Microsoft.VisualStudio.Composition/Microsoft.VisualStudio.Composition.csproj
NuGetSystem.ComponentModel.Composition—src/Microsoft.VisualStudio.Composition/Microsoft.VisualStudio.Composition.csproj
NuGetSystem.Composition—src/Microsoft.VisualStudio.Composition/Microsoft.VisualStudio.Composition.csproj
NuGetSystem.Reflection.Emit—src/Microsoft.VisualStudio.Composition/Microsoft.VisualStudio.Composition.csproj
NuGetSystem.Reflection.Metadata—src/Microsoft.VisualStudio.Composition/Microsoft.VisualStudio.Composition.csproj
NuGetSystem.Threading.Tasks.Dataflow—src/Microsoft.VisualStudio.Composition/Microsoft.VisualStudio.Composition.csproj
All dependencies 33

Full resolved dependency set from the GitHub dependency graph: 18 direct and 15 indirect (transitive) packages. The transitive closure is complete when the repository commits a lockfile.

RegistryPackageVersionRelation
NuGetMicrosoft.CodeAnalysis.Analyzers—direct
NuGetMicrosoft.CodeAnalysis.Common—direct
NuGetMicrosoft.CodeAnalysis.CSharp—direct
NuGetMicrosoft.CodeAnalysis.CSharp.Workspaces—direct
NuGetMicrosoft.CodeAnalysis.VisualBasic—direct
NuGetMicrosoft.VisualStudio.Threading.Analyzers—direct
NuGetMicrosoft.VisualStudio.Threading.Only—direct
NuGetMicrosoft.VisualStudio.Validation—direct
NuGetNerdbank.MessagePack—direct
NuGetNerdbank.MSBuildExtension—direct
NuGetNerdbank.NetStandardBridge—direct
NuGetOpenSoftware.DgmlBuilder—direct
NuGetSystem.CommandLine.DragonFruit—direct
NuGetSystem.ComponentModel.Composition—direct
NuGetSystem.Composition—direct
NuGetSystem.Reflection.Emit—direct
NuGetSystem.Reflection.Metadata—direct
NuGetSystem.Threading.Tasks.Dataflow—direct
NuGetBenchmarkDotNet—indirect
NuGetDiffPlex—indirect
NuGetMicrosoft.CodeAnalysis.CSharp.CodeFix.Testing—indirect
NuGetMicrosoft.CodeAnalysis.VisualBasic.CodeFix.Testing—indirect
NuGetMicrosoft.CodeAnalysis.VisualBasic.Workspaces—indirect
NuGetMicrosoft.CSharp—indirect
NuGetMicrosoft.NET.Test.Sdk—indirect
NuGetMicrosoft.VisualStudio.DiagnosticsHub.BenchmarkDotNetDiagnosers—indirect
NuGetSystem.Composition.AttributedModel—indirect
NuGetSystem.Memory—indirect
NuGetxunit—indirect
NuGetxunit.extensibility.execution—indirect
NuGetxunit.runner.console—indirect
NuGetxunit.runner.visualstudio—indirect
NuGetXunit.SkippableFact—indirect
Dependency advisories not assessed

Advisory matching could not run for this report: No resolved dependencies carried a version and a supported ecosystem

Raw JSON report machine-readable

Feedback

Spotted something off in this report, or have thoughts to share? Wrong measurements, missed tooling, ideas, questions — anything is welcome. Every message is read and gets a response.

The message is kept through sign-in.

Related records

Inspected repositories sharing catalogue tags or ecosystems with microsoft/vs-mef. Read them side by side →

91microsoft/VSSDK-AnalyzersRoslyn analyzers for Visual Studio extensionsExcellent59cwinland/FastMoqProvider‑first .NET testing framework for auto‑mocking, DI‑driven test creation, and optional Moq compatibility.Moderate98dotnet/msbuildThe Microsoft Build Engine (MSBuild) is the build platform for .NET and Visual Studio.Exceptional98microsoft/vstestVisual Studio Test Platform is the runner and engine that powers test explorer and vstest.console.Exceptional97Azure/azure-functions-dotnet-workerAzure Functions out-of-process .NET language workerExceptional94microsoft/vs-threadingThe Microsoft.VisualStudio.Threading is a xplat library that provides many threading and synchronization primitives used in Visual Studio and other applications. Exceptional

Scores are signals, not warranties. They reflect publicly visible practices on GitHub — not a code audit, and not a security guarantee.

Missing data is excluded and weights renormalized, never scored as zero. Methodology is versioned and open: metrics v2.10.0, schema v0.34.0 — full methodology · metrics wiki.

How one result sits in the wider record: aggregate statistics — NuGet.