Public record
Software health reportschema 0.15.0 · metrics 2.10.0 · 2026-07-20 14:15 UTC

mbj / mutant

Mutation testing for Ruby. AI writes your code. AI writes your tests. But who tests the tests?

RubyCustom license★ 2,170 stars⑂ 161 forkssince Jul 2012View on GitHub ↗
KindLibraryNetwork serviceCommand-line toolhow this is determined

mbj/mutant holds a health index of 87 out of 100, placing it in the Excellent band. It scores highest on Vitality (90/100) and lowest on AI Readiness (36/100). It was last updated 5 days ago. A single contributor accounts for most of its recent work.

87
overall / 100
Excellent

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.

87
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 73 is calibrated to 87 on the published index scale (record calibration 2026-08-02).

Ownership

Markus SchirpPersonal account
290 followers166 public repossince Aug 2009Schirp DSO LTD

This repository is owned by a personal account. A single-owner project carries more continuity risk than an organization-backed one.

Package ecosystems

RegistryPackageVersionDownloads / moVersionsLast publishTags
crates.iomanagerpoints to another repo — not scored0.1.03222194 days agoartificedatabasepermissions
RubyGemsmutant-minitest0.16.3-10380 days ago
RubyGemsmutant-rspec0.16.3-13980 days ago
RubyGemsmutant0.16.3-22480 days ago

Metrics by category

Vitality

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

90Excellent · 21% of overall
How it's scored
36/36Push recencylast push 5 days ago
20.1/36Commit cadence29/52 weeks with commits
18/18Commit volume297 commits in the last year
10/10OpenSSF Scorecard: Maintained20 commit(s) and 2 issue activity found in the last 90 days -- score normalized to 10
Inputs used
commits_last_year297
human_commit_share
days_since_last_push5
active_weeks_last_year29

Release discipline

100Exceptional
How it's scored
27/27Ships releases5 releases published
36/36Release recencylatest release 90 days ago
27/27Release cadencea release every ~14.8 days
0/10OpenSSF Scorecard: Signed-Releasesno data
Inputs used
releases_count5
latest_release_tagv0.16.2
releases_from_tagsno
days_since_latest_release90
mean_days_between_releases14.8
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?

76Good · 17% of overall
How it's scored
54.1/60Stars2,170 stars
18.4/25Forks161 forks
8.1/15Watchers30 watchers
Inputs used
forks161
stars2,170
watchers30
growth_stateunverified
growth_factor_pct100
growth_unverified_reasonno_history
How it's scored
22.5/22.5README
16.9/22.5Licenselicense file present, not a recognized license
18/18CONTRIBUTING guide
0/13.5Code of conduct
0/7.2Issue template
0/6.3PR template
Inputs used
has_readmeyes
has_licenseyes
readme_badges
has_contributingyes
has_issue_templateno
has_code_of_conductno
readme_badge_services
has_pull_request_templateno
How it's scored
68.4/80Total downloads3,866,046 downloads all-time across rubygems
0/20Registry dependentsnot reported by this ecosystem
Inputs used
packagesmutant-minitest, mutant-rspec, mutant
dependents
ecosystemsrubygems
total_downloads3,866,046
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?

65Good · 23% of overall
How it's scored
9/54Bus factor1 contributor(s) cover half of all commits
4/22.5Commit distributiontop contributor authored 82% of commits
13.5/13.5Contributor breadth55 contributors
10/10OpenSSF Scorecard: Contributorsproject has 35 contributing companies or organizations
Inputs used
bus_factor1
contributors_sampled55
top_contributor_share0.821
How it's scored
32.9/42Issue resolution78% of issues closed
26.1/30PR acceptance954/1,098 decided PRs merged
0/13Newcomer PR acceptanceno first-time contributor's PR decided in 30d
3/15OpenSSF Scorecard: Code-ReviewFound 2/9 approved changesets -- score normalized to 2
Inputs used
merged_prs954
open_issues116
closed_issues418
prs_merged_7d
prs_decided_7d
prs_merged_30d
prs_decided_30d
issue_closed_ratio0.783
closed_unmerged_prs144
first_time_authors_30d
first_time_prs_merged_30d
first_time_prs_decided_30d
Excluded from scoring (no data or not applicable): Newcomer PR acceptance. Remaining weights renormalized.
How it's scored
10/30Ownership backingpersonal (user) account
0/20Verified domainnot applicable to user accounts
17.7/25Owner reach290 followers of mbj
25/25Track record166 public repos, account ~16 yr old
Inputs used
followers290
owner_typeUser
is_verified
owner_loginmbj
public_repos166
account_age_days6,176
Excluded from scoring (no data or not applicable): Verified domain. Remaining weights renormalized.

Package maintenance

100Exceptional
How it's scored
25/25Published & resolvable3 package(s) on rubygems
35/35Publish recencylatest publish 80 days ago
20/20Version history224 published versions
20/20Not deprecatedactive, not deprecated or yanked
Inputs used
packagesmutant-minitest, mutant-rspec, mutant
ecosystemsrubygems
any_deprecatedno
min_days_since_publish80

Engineering Quality

Are baseline engineering and documentation practices in place?

80Excellent · 19% of overall
How it's scored
24/24CI workflows1 workflow(s)
24/24Tests present
16/16Linter config.rubocop.yml
0/9.6Pre-commit hooks
0/6.4.editorconfig
20/20OpenSSF Scorecard: CI-Tests14 out of 14 merged PRs checked by a CI test -- score normalized to 10
Inputs used
has_ciyes
has_testsyes
has_editorconfigno
has_linter_configyes
has_precommit_configno
How it's scored
30/30README
25/25Documentation directory
0/15Documentation / homepage site
10/10Repository description
10/10Topics10 topics
0/10Wiki
Inputs used
topicsmutation-testing, ruby, coverage, rspec, minitest, code-review, code-quality-analyzer, mutant, static-analysis, dynamic-analysis
has_wikino
homepage
docs_site
has_readmeyes
has_docs_diryes
has_descriptionyes

Security

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

57Moderate · 16% of overall
How it's scored
7.5/7.5Binary-Artifactsno binaries found in the repo
0/7.5Branch-Protectionno data
2.5/2.5CI-Tests14 out of 14 merged PRs checked by a CI test -- score normalized to 10
0/2.5CII-Best-Practicesno effort to earn an OpenSSF best practices badge detected
1.5/7.5Code-ReviewFound 2/9 approved changesets -- score normalized to 2
2.5/2.5Contributorsproject has 35 contributing companies or organizations
10/10Dangerous-Workflowno dangerous workflow patterns detected
7.5/7.5Dependency-Update-Toolupdate tool detected
0/5Fuzzingproject is not fuzzed
2.2/2.5Licenselicense file detected
7.5/7.5Maintained20 commit(s) and 2 issue activity found in the last 90 days -- score normalized to 10
0/5Packagingno data
0/5Pinned-Dependenciesdependency not pinned by hash detected -- score normalized to 0
0/5SASTSAST tool is not run on all commits -- score normalized to 0
0/5Security-Policysecurity policy file not detected
0/7.5Signed-Releasesno data
0/7.5Token-Permissionsdetected GitHub workflow tokens with excessive permissions
7.5/7.5Vulnerabilities0 existing vulnerabilities detected
Inputs used
sourceopenssf_scorecard
checks_evaluated15
scorecard_versionv5.5.0
checks_inconclusive3
scorecard_aggregate5.7
Excluded from scoring (no data or not applicable): Branch-Protection, 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.

36Weak · 4% of overall
How it's scored
0/45Agent instructionsno CLAUDE.md / AGENTS.md / editor rules
0/15Machine-readable docs (llms.txt)
0/40Legible commit historyno data
Inputs used
has_llms_txtno
llms_txt_url
legible_history_share
agent_instruction_files
agent_instruction_max_bytes
Excluded from scoring (no data or not applicable): Legible commit history. Remaining weights renormalized.
How it's scored
0/18One-command bootstrap
22/22Automated tests
11/11Lint / format config.rubocop.yml
0/11Static type checking
10/10Reproducible environmentlockfile
0/10Demonstrated agent practiceno data
5/8Automated maintenancedependency automation configured, none observed in the sampled commits
0/10OpenSSF Scorecard: Pinned-Dependenciesdependency not pinned by hash detected -- score normalized to 0
Inputs used
has_nixno
has_testsyes
lockfilesCargo.lock, Gemfile.lock
has_dockerfileno
typed_languageno
bootstrap_files
has_devcontainerno
has_linter_configyes
typecheck_configs
agent_commit_share
toolchain_manifests
dependency_bot_commit_share0
Excluded from scoring (no data or not applicable): Demonstrated agent practice. Remaining weights renormalized.
How it's scored
0/45Type-checkable codeRuby without a type-check config
55/55Manageable file sizes0/493 source files over 60KB
Inputs used
primary_languageRuby
largest_source_bytes45,738
source_files_sampled493
oversized_source_files0
How it's scored
0/40API schema (OpenAPI/GraphQL/proto)
0/20MCP server
40/40Runnable examplesexample
Inputs used
example_dirsexample
has_mcp_signalno
api_schema_files
interfaces_expected_ofnetwork-service

Key facts

2,170GitHub stars
55contributors
297commits, last 12 months
5days since last push
5releases
1bus factor
116open issues
crates.io, RubyGemspackage ecosystems

Data collection warnings

  • crates package 'manager' points at a different repository (https://github.com/artifice-network/manager); excluded from ecosystem scoring

More detail

OpenSSF Scorecard 5.7 / 10
5.7aggregate

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 · 2026-07-20 14:15 UTC

10Binary-Artifactsno binaries found in the repo
n/aBranch-Protectioninternal error: error during branchesHandler.setup: internal error: some github tokens can't read classic branch protection rules: https://github.com/ossf/scorecard-action/blob/main/docs/authentication/fine-grained-auth-token.md
10CI-Tests14 out of 14 merged PRs checked by a CI test -- score normalized to 10
0CII-Best-Practicesno effort to earn an OpenSSF best practices badge detected
2Code-ReviewFound 2/9 approved changesets -- score normalized to 2
10Contributorsproject has 35 contributing companies or organizations
10Dangerous-Workflowno dangerous workflow patterns detected
10Dependency-Update-Toolupdate tool detected
0Fuzzingproject is not fuzzed
9Licenselicense file detected
10Maintained20 commit(s) and 2 issue activity found in the last 90 days -- score normalized to 10
n/aPackagingpackaging workflow not detected
0Pinned-Dependenciesdependency not pinned by hash detected -- score normalized to 0
0SASTSAST tool is not run on all commits -- score normalized to 0
0Security-Policysecurity policy file not detected
n/aSigned-Releasesno releases found
0Token-Permissionsdetected GitHub workflow tokens with excessive permissions
10Vulnerabilities0 existing vulnerabilities detected
Direct dependencies 18
RegistryPackageVersion constraintManifest
crates.ioclap4.5manager/Cargo.toml
crates.iocmd-proc0.4manager/Cargo.toml
crates.iolog0.4manager/Cargo.toml
crates.ioociman0.3manager/Cargo.toml
crates.iotokio1manager/Cargo.toml
crates.iotoml0.8manager/Cargo.toml
RubyGemsmutant-rspecquick_start/Gemfile
RubyGemsrspecquick_start/Gemfile
RubyGemssimplecovquick_start/Gemfile
RubyGemsdeep-coverquick_start/Gemfile
RubyGemsrailsrails_example/Gemfile
RubyGemspgrails_example/Gemfile
RubyGemssqlite3rails_example/Gemfile
RubyGemspg-ephemeralrails_example/Gemfile
RubyGemsrspecrails_example/Gemfile
RubyGemsrspec-railsrails_example/Gemfile
RubyGemsmutantrails_example/Gemfile
RubyGemsmutant-rspecrails_example/Gemfile
All dependencies 169

Full resolved dependency set from the GitHub dependency graph: 25 direct and 144 indirect (transitive) packages. The transitive closure is complete when the repository commits a lockfile.

RegistryPackageVersionRelation
crates.ioclapdirect
crates.ioclap4.5.53direct
crates.iocmd-procdirect
crates.iocmd-proc0.4.0direct
crates.iologdirect
crates.iolog0.4.29direct
crates.ioocimandirect
crates.ioociman0.3.2direct
crates.iotokiodirect
crates.iotokio1.50.0direct
crates.iotomldirect
crates.iotoml0.8.23direct
RubyGemsdeep-cover1.1.0direct
RubyGemsmutantdirect
RubyGemsmutant0.16.3direct
RubyGemsmutant-rspecdirect
RubyGemsmutant-rspec0.16.3direct
RubyGemspgdirect
RubyGemspg-ephemeraldirect
RubyGemsrspecdirect
RubyGemsrspec3.13.2direct
RubyGemsrspec4.0.0.beta1direct
RubyGemsrspec-railsdirect
RubyGemssimplecov0.22.0direct
RubyGemssqlite3direct
crates.ioanstream0.6.21indirect
crates.ioanstyle1.0.13indirect
crates.ioanstyle-parse0.2.7indirect
crates.ioanstyle-query1.1.5indirect
crates.ioanstyle-wincon3.0.11indirect
crates.ioblock-buffer0.10.4indirect
crates.iobytes1.11.1indirect
crates.iocfg-if1.0.4indirect
crates.ioclap_builder4.5.53indirect
crates.ioclap_derive4.5.49indirect
crates.ioclap_lex0.7.6indirect
crates.iocolorchoice1.0.4indirect
crates.iocpufeatures0.2.17indirect
crates.iocrypto-common0.1.7indirect
crates.iodigest0.10.7indirect
crates.ioequivalent1.0.2indirect
crates.ioerrno0.3.14indirect
crates.iogeneric-array0.14.7indirect
crates.iohashbrown0.16.1indirect
crates.ioheck0.5.0indirect
crates.ioindexmap2.12.1indirect
crates.ioipnet2.12.0indirect
crates.iois_terminal_polyfill1.70.2indirect
crates.ioitoa1.0.17indirect
crates.iolibc0.2.179indirect
crates.iomemchr2.7.6indirect
crates.iomio1.1.1indirect
crates.ionom8.0.0indirect
crates.ioonce_cell_polyfill1.70.2indirect
crates.iopin-project-lite0.2.17indirect
crates.ioproc-macro21.0.104indirect
crates.ioquote1.0.42indirect
crates.iosame-file1.0.6indirect
crates.iosemver1.0.27indirect
crates.ioserde1.0.228indirect
crates.ioserde_core1.0.228indirect
crates.ioserde_derive1.0.228indirect
crates.ioserde_json1.0.148indirect
crates.ioserde_spanned0.6.9indirect
crates.iosha20.10.9indirect
crates.iosignal-hook-registry1.4.8indirect
crates.iostrsim0.11.1indirect
crates.iosyn2.0.112indirect
crates.iothiserror2.0.17indirect
crates.iothiserror-impl2.0.17indirect
crates.iotokio-macros2.6.1indirect
crates.iotoml_datetime0.6.11indirect
crates.iotoml_edit0.22.27indirect
crates.iotoml_write0.1.2indirect
crates.iotypenum1.19.0indirect
crates.iounicode-ident1.0.22indirect
crates.ioutf8parse0.2.2indirect
crates.ioversion_check0.9.5indirect
crates.iowalkdir2.5.0indirect
crates.iowasi0.11.1+wasi-snapshot-preview1indirect
crates.iowinapi-util0.1.11indirect
crates.iowindows-link0.2.1indirect
crates.iowindows-sys0.61.2indirect
crates.iowinnow0.7.14indirect
crates.iozmij1.0.10indirect
RubyGemsadamantium0.2.0indirect
RubyGemsast2.4.3indirect
RubyGemsbackports3.25.3indirect
RubyGemsbigdecimal4.0.1indirect
RubyGemsbinding_of_caller1.0.1indirect
RubyGemscoderay1.1.3indirect
RubyGemsdate3.5.1indirect
RubyGemsdebug_inspector1.2.0indirect
RubyGemsdeep-cover-core1.1.0indirect
RubyGemsdiff-lcsindirect
RubyGemsdiff-lcs1.6.2indirect
RubyGemsdiff-lcs2.0.0indirect
RubyGemsdocile1.4.1indirect
RubyGemsdrb2.2.3indirect
RubyGemserb6.0.4indirect
RubyGemshighline3.1.2indirect
RubyGemsice_nine0.11.2indirect
RubyGemsio-console0.8.2indirect
RubyGemsirbindirect
RubyGemsirb1.17.0indirect
RubyGemsirb1.18.0indirect
RubyGemsjson2.19.3indirect
RubyGemslanguage_server-protocol3.17.0.5indirect
RubyGemslint_roller1.1.0indirect
RubyGemsmemoizable0.4.2indirect
RubyGemsmethod_source1.1.0indirect
RubyGemsminitestindirect
RubyGemsminitest6.0.2indirect
RubyGemsmize0.6.1indirect
RubyGemsmutex_mindirect
RubyGemsmutex_m0.3.0indirect
RubyGemsparallel1.27.0indirect
RubyGemsparserindirect
RubyGemsparser3.3.10.2indirect
RubyGemsparser3.3.11.1indirect
RubyGemspp0.6.3indirect
RubyGemsprettyprint0.2.0indirect
RubyGemsprism1.9.0indirect
RubyGemspry0.16.0indirect
RubyGemspsych5.3.1indirect
RubyGemsracc1.8.1indirect
RubyGemsrainbow3.1.1indirect
RubyGemsrdoc7.2.0indirect
RubyGemsreadline0.0.4indirect
RubyGemsregexp_parserindirect
RubyGemsregexp_parser2.11.3indirect
RubyGemsregexp_parser2.12.0indirect
RubyGemsreline0.6.3indirect
RubyGemsrspec-coreindirect
RubyGemsrspec-core3.13.6indirect
RubyGemsrspec-core4.0.0.beta1indirect
RubyGemsrspec-expectations3.13.5indirect
RubyGemsrspec-expectations4.0.0.beta1indirect
RubyGemsrspec-itsindirect
RubyGemsrspec-its2.0.0indirect
RubyGemsrspec-mocks3.13.7indirect
RubyGemsrspec-mocks3.13.8indirect
RubyGemsrspec-mocks4.0.0.beta1indirect
RubyGemsrspec-support3.13.7indirect
RubyGemsrspec-support4.0.0.beta1indirect
RubyGemsrubocopindirect
RubyGemsrubocop1.86.0indirect
RubyGemsrubocop-ast1.49.1indirect
RubyGemsruby-progressbar1.13.0indirect
RubyGemssecurerandomindirect
RubyGemssecurerandom0.4.1indirect
RubyGemssimplecov-html0.13.2indirect
RubyGemssimplecov_json_formatter0.1.4indirect
RubyGemssorbet-runtimeindirect
RubyGemssorbet-runtime0.6.13055indirect
RubyGemssorbet-runtime0.6.13198indirect
RubyGemsstringio3.2.0indirect
RubyGemssync0.5.0indirect
RubyGemsterm-ansicolor1.11.3indirect
RubyGemsterminal-table4.0.0indirect
RubyGemsthor1.5.0indirect
RubyGemsthread_safe0.3.6indirect
RubyGemstins1.51.1indirect
RubyGemstsort0.2.0indirect
RubyGemsunicode-display_width3.2.0indirect
RubyGemsunicode-emoji4.2.0indirect
RubyGemsunparserindirect
RubyGemsunparser0.9.0indirect
RubyGemswith_progress1.0.1indirect
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.

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 v0.15.0 — full methodology · metrics wiki.

How one result sits in the wider record: aggregate statisticscrates.io, RubyGems.