Reads strong: 3 of 5 rated dimensions are strong, 2 are adequate and none is significant.
106 checks ran across 6 assessable dimensions. Organization & Key-Person Risk and Product & Engineering Maturity are adequate. 1 finding is worth checking first. 7 findings, each with evidence. One dimension cannot be assessed without an acquirer.
This repository reads strong. Show it in your README: the badge links to a page where anyone can check the reading. If you embed it: link it to the report, remove it if the report is delisted, and do not present it as a certification or an endorsement.
[](https://borehole.dev/verify/ZCB3BKBQ3MSW?via=badge)
Borehole's proprietary scoring is calibrated across hundreds of repositories. Each finding here reads significant, but its check has not yet held up often enough in that calibration to rate significant on its own. If one holds when someone checks it, it is significant.
- 03.5 The contributor who wrote a quarter or more of this has not committed here for more than a year
| Dimension | Rating | ||
|---|---|---|---|
| 01 | Architecture & Codebase — including AI provenance | strong | |
| 02 | Engineering Process & SDLC Maturity | strong | |
| 03 | Organization & Key-Person Risk | adequate | |
| 04 | Product & Engineering Maturity | adequate | |
| 05 | Security & Reliability Posture | strong | |
| 06 | Observability & Operations | not assessable | |
| 07 | Fit with the Acquirer | not assessable |
- 6% of non-merge commits carry any trailer at all
- low trailer coverage: the convention may not be in consistent use
- no widespread author/committer date divergence
- deep scan blamed 1,578 of 1,578 counted files
Architecture & Codebase — including AI provenance
01 · strong · ratings ↑src/fcs-fable/src/Compiler/Checking/Expressions/CheckExpressions.fs is 12,984 lines, 74× this codebase's median file
adequateThe median source file here is 175 lines. 57 files exceed 1,750 lines, the largest being 12,984. Size is not a defect on its own — some problems genuinely live in one place — but these are where merge conflicts, review fatigue and single-owner knowledge concentrate, and they are the first thing that slows an inheriting engineer down.
A note that does not affect this rating: measured against its own codebase's median, it is below the 85th percentile of 382 surveyed projects' largest files, where this check begins to count.
| line-count | src/fcs-fable/src/Compiler/Checking/Expressions/CheckExpressions.fs:1 — 12,984 lines (74× median) |
| line-count | src/fcs-fable/src/Compiler/CodeGen/IlxGen.fs:1 — 12,365 lines (70× median) |
| line-count | src/fcs-fable/src/Compiler/TypedTree/TypedTreeOps.fs:1 — 11,970 lines (68× median) |
| line-count | src/Fable.Transforms/Rust/Fable2Rust.fs:1 — 6,463 lines (36× median) |
| line-count | src/Fable.Transforms/Beam/Replacements.fs:1 — 6,427 lines (36× median) |
Respond to this finding
Your response is published beside the finding, not instead of it. A finding you can argue with is the point — and a wrong one is calibration data we want.
An owner's response is removed only when it is unlawful, impersonates someone, publishes personal data or a credential, or is not about the finding. Disagreeing with the report is never a reason. To report a response, or to reach us about one, write to takedown@borehole.dev.
Engineering Process & SDLC Maturity
02 · strong · ratings ↑Almost no process scaffolding exists in the repository
adequateOf five ordinary markers — CI workflows, CODEOWNERS, a pull-request template, pre-commit hooks, contribution guidance — 1 is present: CI workflows. Branch protection itself is a GitHub setting rather than a file, so this is a reading of proxies and not of the rules themselves. What it does establish is that the process is not written down anywhere a new engineer would find it.
A note that does not affect this rating: in Borehole's calibration, this check's notes were usually true but overstated.
| process-scaffolding | 1 of 5 markers present across 1,657 tracked files |
Respond to this finding
Your response is published beside the finding, not instead of it. A finding you can argue with is the point — and a wrong one is calibration data we want.
An owner's response is removed only when it is unlawful, impersonates someone, publishes personal data or a credential, or is not about the finding. Disagreeing with the report is never a reason. To report a response, or to reach us about one, write to takedown@borehole.dev.
Organization & Key-Person Risk
03 · adequate · ratings ↑The contributor who wrote a quarter or more of this has not committed here for more than a year
adequate worth checking firstOne person authored a quarter or more of 6,686 commits and has not committed here for more than a year, while the repository has kept moving. The concentration figure alone would not show this. Whoever is changing this code now is not the person who wrote most of it, which is the situation an acquirer is usually told they are avoiding. The history shows only that no commits of theirs landed here, not why.
The check that found this reads significant, but it has not yet held up often enough in Borehole's calibration to rate a finding significant on its own. If it holds when someone checks it, this finding is significant.
| last-commit-by-top-author | last commit more than a year ago, measured to the survey |
| git shortlog -sn | top author a quarter or more of 6,686 commits |
Respond to this finding
Your response is published beside the finding, not instead of it. A finding you can argue with is the point — and a wrong one is calibration data we want.
An owner's response is removed only when it is unlawful, impersonates someone, publishes personal data or a credential, or is not about the finding. Disagreeing with the report is never a reason. To report a response, or to reach us about one, write to takedown@borehole.dev.
Product & Engineering Maturity
04 · adequate · ratings ↑Fixes are 56% of recent work, up from 37%
adequateIn the last two quarters 56% of commits were fixes, against 37% in the quarters before. Rising fix work usually means quality debt is coming due, and it takes time that new work would have had.
| fix share by quarter | 62%, 50%, 50%, 42%, 44%, 36%, 23%, 26% |
Respond to this finding
Your response is published beside the finding, not instead of it. A finding you can argue with is the point — and a wrong one is calibration data we want.
An owner's response is removed only when it is unlawful, impersonates someone, publishes personal data or a credential, or is not about the finding. Disagreeing with the report is never a reason. To report a response, or to reach us about one, write to takedown@borehole.dev.
Security & Reliability Posture
05 · strong · ratings ↑The build runs third-party code it does not pin
adequate10 third-party CI actions are referenced by a tag or branch rather than a commit, so they run whatever that tag points to on the day. Tags have been moved to malicious commits in real supply-chain attacks, and a piped script is whatever the server returns that minute. Pinning to a commit is the fix, and it is small.
A note that does not affect this rating: notes like it are common in well-run projects.
| .github/workflows/build.yml | .github/workflows/build.yml:157 — action pinned by tag |
| .github/workflows/build.yml | .github/workflows/build.yml:214 — action pinned by tag |
Respond to this finding
Your response is published beside the finding, not instead of it. A finding you can argue with is the point — and a wrong one is calibration data we want.
An owner's response is removed only when it is unlawful, impersonates someone, publishes personal data or a credential, or is not about the finding. Disagreeing with the report is never a reason. To report a response, or to reach us about one, write to takedown@borehole.dev.
2 locked dependencies have published vulnerabilities, 3 high or critical
adequate2 of 209 locked dependencies match 4 published advisories in OSV, 3 of them rated high or critical. A lockfile says which version is installed, not whether the flawed code is reachable from this product, so each needs a look. Most are fixed by an upgrade, and the advisory names the version. None of the high or critical ones is in what the product ships: only the build reaches them: a bundler, a code generator, a build plugin, or a lockfile in a tooling directory.
A note that does not affect this rating: in Borehole's calibration, this check's notes were usually true but overstated.
| package-lock.json | package-lock.json — brace-expansion 5.0.9: GHSA-6j4f-fj2g-mc7p (high), fixed in 5.0.10; reached only by the build |
| package-lock.json | package-lock.json — braces 3.0.3: GHSA-vfj7-8cjw-p6xm (high); reached only by the build |
Respond to this finding
Your response is published beside the finding, not instead of it. A finding you can argue with is the point — and a wrong one is calibration data we want.
An owner's response is removed only when it is unlawful, impersonates someone, publishes personal data or a credential, or is not about the finding. Disagreeing with the report is never a reason. To report a response, or to reach us about one, write to takedown@borehole.dev.
1 vendored component with no licence
adequateThird-party code is committed into this repository without any statement of the terms it arrived under. Unknown terms are harder to deal with than inconvenient ones: an awkward licence can be complied with, an absent one cannot. Each of these needs its origin established before the code changes hands.
A note that does not affect this rating: in Borehole's calibration, this check's notes were usually true but overstated.
| src/fable-library-rust/vendored/hashable | src/fable-library-rust/vendored/hashable — 2 tracked files, no licence file |
Respond to this finding
Your response is published beside the finding, not instead of it. A finding you can argue with is the point — and a wrong one is calibration data we want.
An owner's response is removed only when it is unlawful, impersonates someone, publishes personal data or a credential, or is not about the finding. Disagreeing with the report is never a reason. To report a response, or to reach us about one, write to takedown@borehole.dev.
Observability & Operations
06 · not assessable · ratings ↑Not rated: only 5 of 16 checks could reach a conclusion here; the rest do not apply to this repository or could not read it. What a person adds here.
Fit with the Acquirer
07 · not assessable · ratings ↑Not rated: structurally not assessable from a repository. What a person adds here.
Check it on the running system
4 checks against the running system follow from the findings above: what a buyer's engineer will try, how to run it first, and what to have ready. A paid survey of this repository includes them.
A paid survey of a public repository is also reviewed: a language model reads each finding against the code and withdraws only findings it judges the code contradicts, each listed with its reason. The review is a language model's reading of the findings against the code, and it can be wrong. It never adds a finding, never raises a band, and never removes a finding from a proven check or an advisory that affects the surveyed version.
What a person adds
The survey reads what the repository can show. The code cannot settle these questions, and on them this report states nothing. Each says where its answer lives: your own engineer, the company, or an assessor you choose can settle it. Questions marked measured open with something this repository shows.
Architecture & Codebase — including AI provenance
01 · full coverage- measured No architecture or design document is in the tree, across 1,097 product files. Where does the design live, and who holds it?
- Is the architecture right for the next three years of the product?
- Were the home-grown components reasonable choices when they were made, and are they now?
Engineering Process & SDLC Maturity
02 · high coverage- Is review real or a rubber stamp? Comment depth and time to approve need the pull request history.
- Is delivery planned and measured, or heroic?
- How are incidents run, reviewed and learned from?
Organization & Key-Person Risk
03 · partial coverage- measured One contributor authored a quarter or more of the commits in this history. Is that person part of the transaction, and for how long after it?
- Who mentors whom, and would that survive a departure?
- Can the team grow, and who stands behind the top three contributors?
- Is the seniority mix sound, and will pay survive your salary bands?
- Is the pace sustainable? Commit times cannot say: git keeps no reliable local time.
- Does the team want to stay after close?
- How are decisions made and disagreements resolved?
Product & Engineering Maturity
04 · minimal coverage- measured 503 commits landed in the last year, against 211 the year before (+138%). What drove it: new people, a deadline, or code produced faster than before?
- Can this team deliver the stated roadmap on the stated timeline?
- Does leadership know about the debt, and is time budgeted to repay it?
- Is the engineering shape consistent with the commercial story?
Security & Reliability Posture
05 · partial coverage- What has actually broken, how often, and how badly?
- What did external testing find, and was it fixed?
- What is the SOC 2, ISO 27001 or GDPR status, and where is the evidence?
Observability & Operations
06 · partial coverageNot rated: only 5 of 16 checks could reach a conclusion here; the rest do not apply to this repository or could not read it.
- Are the dashboards opened, the alerts acknowledged and the pages answered?
- Are the service-level objectives actually met?
- Who carries the pager, and how often does it go off?
- What does it cost to run, and how much headroom is there?
Fit with the Acquirer
07 · none coverageNot rated: structurally not assessable from a repository.
- This is primarily a F# codebase. Does your engineering organisation already run F# in production, or would this be the first?
- The bulk of this system sits in src/, lib/, tests_external/. Which of your existing systems would each of those have to absorb or replace?
- Nothing in the repository says how this is deployed. Is it shipped as a library, a binary or a service, and if it runs somewhere, who owns that environment?
- What is your tolerance for the findings above remaining unaddressed for the first two quarters after close, given everything else that will compete for this team's time?
- Which of these systems duplicate yours, and which get retired?
- What will integration cost, and in what order?
- Where does the team land in your organisation, and who reports to whom?
- Are there earn-outs, retention packages or contractor IP to assign?
- Do customer contracts limit hosting, regions or vendors?
A human assessment is Borehole's own paid service, €12,000+ (total price is determined per engagement; travel billed at cost). It is not independent of this report: the same business produced both. It is a separate contract, with its own scope, terms and reliance.
Embed the badge
Tied to this commit and this date, and it fades after 90 days — an honest badge is one that expires. A repository with significant findings gets a neutral "read" badge rather than a red one: the library is where the range is visible, not someone else's README.
[](/r/fable-compiler/fable/67b6324)
If you embed it: link it to the report, remove it if the report is delisted, and do not present it as a certification or an endorsement.
Rejection log — 99 signals that ran and did not fire
Appendix: rejection log — 99 signals that ran and did not fire
Published on purpose. A signal that looked and decided not to fire has told you something, and this is the calibration data behind every threshold above.
Looked, and found nothing — 66
| Signal | What it found |
|---|---|
| 04.hotspot_concentration | change is spread across the codebase rather than pooling in a few filesfiles 7,558 · top5 share 0.054 |
| 04.debt_markers | debt markers are sparsemarkers 727 · per kloc 1.13 · lines read 646,202 |
| 04.dependency_sprawl | direct dependency counts are unremarkable |
| 04.test_growth | test effort kept pace with code writtenlate test per code 0.205 · early test per code 0.057 |
| 04.churn_trend | rework is not rising against new worklate delete per insert 0.663 · early delete per insert 0.64 |
| 04.fixes_with_tests | fixes usually come with a testfixes 337 · share 0.763 · with tests 257 |
| 06.telemetry_presence | this repository does not deploy a running service, so instrumentation is not expected of itbasis nothing in this repository deploys a long-running server; if it runs as one, its deployment lives elsewhere · files read 1,477 |
| 06.structured_logging | not a running service; structured logging is not expected of a librarybasis nothing in this repository deploys a long-running server; if it runs as one, its deployment lives elsewhere |
| 06.healthcheck_presence | not a running service, so a health endpoint is not expectedbasis nothing in this repository deploys a long-running server; if it runs as one, its deployment lives elsewhere |
| 06.usage_reporting_default | the product's code names no reporting hostsettings on 0 · settings off 0 |
| 06.migrate_on_start | migrations do not run at container start |
| 03.contributor_concentration | no single contributor dominates the last 24 monthsyears 10.7 · window last 24 months · authors 176 |
| 03.active_contributors | more than one contributor active in the trailing yearall time 176 · active 12mo 20 |
| 03.knowledge_silos | every substantial directory has been touched by more than one personauthors 176 · directories 3 |
| 03.drive_by_contributors | an open contributor base, where one-commit contributors are normalauthors 176 · one off share 0.42 |
| 03.critical_path_ownership | more than one person changes the critical pathsauthors 26 |
| 03.second_contributor_attrition | the second and third contributors are still active |
| 03.bus_factor_trend | the team has not narrowed to one person |
| 03.joiners_and_leavers | the team is not shrinkingleft 1 · joined 3 · regular last year 6 |
| 02.merge_discipline | a meaningful share of recent change carries evidence of reviewmerges 0 · window last 24 months · with tracked 15 |
| 02.ci_presence | CI configuration is present in the working treecount 10 |
| 02.test_presence | tests are present in a normal proportion to sourcetests 443 · source 1,276 · test ratio 0.347 |
| 02.release_cadence | tags are presenttags 318 |
| 02.conventional_commits | commit subjects generally carry contentsampled 6,914 · low content share 0.054 |
| 02.ci_runs_tests | CI invokes a test runnerconfigs 9 · with tests 1 |
| 02.skipped_tests | few tests are switched offfocused 0 · skipped 0 · test files 529 |
| 02.ci_test_gating | no test run in CI is written so that it cannot failconfigs 10 |
| 02.revert_share | change is rarely undoneshare 0.003 · reverts 2 · recent commits 715 |
| 02.dependency_update_cadence | dependencies move with the codelockfiles 9 · commits since 1 · days since lockfile changed 0 |
| 02.flaky_test_markers | tests are not retried until they passtest retries 0 · suite retries 0 |
| 02.lint_in_build | a linter or formatter runs in the buildwired 8 · ci configs 10 · product files 834 |
| 02.commit_size | changes arrive in reviewable sizesshare 0.038 · commits 609 · over 2000 lines 23 |
| 01.burst_import | no commit run met both the rate and the net-addition thresholdgap seconds 180 · min add ratio 3.0 · min net added 2,000 |
| 01.initial_dump | first commit is not a disproportionate share of the codebaseinsertions 2,362 · share of insertions 0.0008 |
| 01.message_uniformity | commit subjects vary in wording and lengthlength stdev 20.04 · repeat share 0.074 |
| 01.revision_depth | most files were revisited after they were first writtenfiles seen 980 · write once share 0.142 |
| 01.duplicated_blocks | little shipping code is repeated verbatim across filesshare 0.0226 · product files 832 · distinct blocks 310,630 |
| 01.swallowed_errors | errors are rarely thrown awayloc 647,582 · files 2 · per kloc 0.0 |
| 01.unfinished_migration | no language migration is stalled halfway |
| 01.weights_in_git | no model weights are committedfiles 0 |
| 05.committed_secrets | no credential-shaped strings outside test and fixture pathsnote the working tree only; the history is 05.5 · patterns 8 · files read 1,477 |
| 05.security_guardrails | at least one standard guard rail is configured |
| 05.dependency_pinning | a lockfile is committed, so builds are reproduciblelockfile True |
| 05.license_present | a licence file is presentfound True |
| 05.secrets_in_history | no credential-shaped string was ever added outside test and fixture pathspatterns 8 · truncated False · added lines 2,543,441 |
| 05.secrets_management_pattern | no environment file is committed outside tests and examplesenv files 0 |
| 05.shell_from_strings | product code does not build shell commands from stringssites 0 |
| 05.unsafe_deserialization | no code-executing deserialiser in product codesites 0 |
| 05.tls_verification_off | no TLS verification is switched off in product codefiles 0 · sites 0 · pinned instead 0 |
| 05.privileged_workloads | no workload runs privileged or in the host's namespacessites 0 · behind a setting or built here 0 |
| 05.credentials_in_deploy_config | deployment configuration references secrets, never holds themfiles 0 · sites 0 |
| 05.signing_material | no signing keystore or profile is committedfiles 0 |
| 05.cleartext_traffic | plain HTTP is not allowed app-widesites 0 |
| 05.license_copyleft_inherited | every licence found in vendored code is permissive or weak-copyleftvendored paths 11 |
| 05.license_manifest_conflict | manifest and licence file agree on MITlicense MIT |
| 05.license_grant_unclear | the licence is recognisable as MITclass permissive · license MIT |
| 05.committed_native_libraries | no widely used compiled library is committed to the productlibraries 3 |
| 04.dependency_churn | few dependencies were added and dropped within 60 daysdependencies seen 163 · added in two years 29 · removed within 60 days 0 |
| 04.ci_platforms_dropped | no platform was dropped from CI in the last two years |
| 04.repository_status | the README's first screen states no end, move or freezestatements 0 |
| 02.development_elsewhere | nothing says development happens elsewhereno pr statements 0 · mirror statements 0 · replayed commit share 0.0 |
| 05.licence_changes | relicensed only between permissive licences: Apache-2.0 → MIT (2017-12-05)latest MIT · weaker False · licence versions 2 |
| 05.paid_edition | no directory carries a separate paid-edition licencedirectories 0 |
| 04.releases_stopped | releases keep pace with developmentmedian gap days 3.5 · days since last tag -4 · commits last 90 days 298 |
| 04.release_branch | the newest release, 5.19.0, was made after the surveyed commit on the branch surveyedelsewhere 20 · on branch 228 · tags in window 249 |
| 03.single_maintainer | no file says one person maintains itstatements 0 |
Could not conclude, or did not apply — 33
Not a clean result. Each says why it could not answer here.
| Signal | Why |
|---|---|
| 04.eol_runtime | no pinned runtime version to check |
| 04.schema_churn | no schema migrations to read |
| 04.compat_layers | a library, whose compatibility code is usually deliberate |
| 04.dependency_redundancy | no JavaScript manifest to read |
| 06.telemetry_depth | not expected of it: nothing in this repository deploys a long-running server; if it runs as one, its deployment lives elsewhere |
| 06.print_logging | not expected of it: nothing in this repository deploys a long-running server; if it runs as one, its deployment lives elsewhere |
| 06.correlation_ids | not expected of it: nothing in this repository deploys a long-running server; if it runs as one, its deployment lives elsewhere |
| 06.error_reporting | not expected of it: nothing in this repository deploys a long-running server; if it runs as one, its deployment lives elsewhere |
| 06.alert_rules | not expected of it: nothing in this repository deploys a long-running server; if it runs as one, its deployment lives elsewhere |
| 06.deployed_image_floats | not expected of it: nothing in this repository deploys a long-running server; if it runs as one, its deployment lives elsewhere |
| 06.probes_identical | no Kubernetes probes |
| 06.single_replica | no Kubernetes deployments |
| 06.environment_branching | not expected of it: nothing in this repository deploys a long-running server; if it runs as one, its deployment lives elsewhere |
| 06.release_markers | not expected of it: nothing in this repository deploys a long-running server; if it runs as one, its deployment lives elsewhere |
| 06.feature_flags | no feature-flag service; flags may live elsewhere |
| 02.long_lived_branches | too few merges to judge (squash and rebase leave none) |
| 01.build_reproducibility | no product Dockerfile to read |
| 01.notebook_outputs | not a data or machine-learning repository |
| 05.container_runs_as_root | no Dockerfile outside development, test and example paths |
| 05.outbound_timeouts | not a running service |
| 05.migration_reversibility | too few migrations to judge |
| 05.sql_from_strings | not a running service; a library that builds SQL is doing its job |
| 05.resource_limits | no Kubernetes workload manifests |
| 05.public_env_secret | not a frontend |
| 05.unsafe_html | not a frontend |
| 05.source_maps_shipped | not a frontend |
| 05.dataset_provenance | not a data or machine-learning repository |
| 04.flags_accumulating | few or no feature flags in the history |
| 04.api_versions_coexisting | not a running service |
| 04.deprecations_lingering | a library, which keeps deprecated interfaces for its users |
| 05.project_advisories | record incomplete: no advisory found in the sources that answered; NVD: 4 records name fable with nothing tying them to this repository (CVE-2025-46447, CVE-2025-46468, CVE-2025-46539, …) |
| 05.advisory_record | record incomplete: no advisory against the project in the last 24 months; NVD: 4 records name fable with nothing tying them to this repository (CVE-2025-46447, CVE-2025-46468, CVE-2025-46539, …) |
| 05.project_exploited | no affecting advisory is on CISA's Known Exploited list |
Anyone can check this report against the authoritative record — click the stamp, or enter ZCB3-BKBQ-3MSW at borehole.dev/verify.
The code commits to the 106 checks this run performed, the bands they produced, and the commit they were read at. It does not cover checks written since.
A survey is a reading by a particular version of the assessor. Older readings are kept rather than replaced, because a verification mark attests to the survey it was issued for — overwriting one would make every code already in circulation read as tampered.
| Read | Assessor | Findings | Band |
|---|---|---|---|
| 2026-10-04 · shown | borehole 0.7.13 | 7 | strong |
5 earlier (show)
| 2026-10-03 | borehole 0.7.12 | 7 | strong |
| 2026-10-03 | borehole 0.7.11 | 7 | strong |
| 2026-10-02 | borehole 0.7.10 | 7 | strong |
| 2026-10-01 | borehole 0.7.9 | 7 | adequate |
| 2026-09-30 | borehole 0.7.8 | 7 | adequate |
Where this scan ran
This scan ran on ordinary cloud infrastructure (cloud-run), not in a hardware-isolated confidential VM. Nothing about it is attested by Google.
What an attested survey proves, and what it does not.
What this scan did with the repository — 3 steps
Written by the steps themselves as they ran, not described afterwards. A hand-written account of a data flow drifts the first time somebody changes the flow and not the account.
| At | Step | Detail |
|---|---|---|
| 0.0s | re-read from the facts kept at the last survey; nothing was cloned | facts version: 1d7c04ef8dca7905 |
| 7.3s | ran the deterministic checks | blame pass: Trueread working tree: False |
| 7.3s | recorded where this scan ran | attested: Falseenvironment: cloud-run |
Total 7.3s ·source content sent off this machine: none · calls to a language model: 0 · the clone was deleted when the survey ended
An automated reading of a repository's code and its history up to one commit, with public advisory records. It may be wrong, it is not legal, financial, investment or security advice, and it does not replace diligence by a qualified person. It is provided for information: nobody may rely on it (Borehole's terms, section 3).