#Fingerprint baselines

Baselines let teams turn on CI failOn without fixing every legacy finding on day one. New fingerprints still fail the gate; known debt is tracked in a checked-in file and should shrink over time.

For whole-rule "off", severity overrides, packs, and failOn, see Suppressions and allowlists.

Baselines are debt, not a permanent mute. Prefer fixing findings. Use a baseline only for incremental adoption, and prune entries as debt is paid. Do not add per-line eslint-disable-style source comments — fingerprint baselines are enough for v1.

#File format

Check in mfdoctor.baseline.json (JSON only; JSON Schema: @tonoizer/mfdoctor/schemas/baseline.schema.json):

{
  "schemaVersion": 1,
  "entries": [
    {
      "fingerprint": "a1b2c3…",
      "ruleId": "shared/singleton-mismatch",
      "project": "host",
      "reason": "Legacy singleton until shared migration lands"
    }
  ]
}

Each entry is keyed by finding fingerprint. Optional ruleId and project narrow the match (both must agree when present). Optional reason is copied onto the finding as suppressionReason for reports.

#Generate and update

1. Run MFDoctor so .mf/doctor/report.json exists (plugin build or mfdoctor check / mfdoctor federation).
2. Create a baseline from that report:

mfdoctor baseline generate .mf/doctor/report.json --out mfdoctor.baseline.json

3. After more findings appear, merge them into the baseline without removing existing entries:

mfdoctor baseline update .mf/doctor/report.json --out mfdoctor.baseline.json

4. When debt is paid, drop unused fingerprints:

mfdoctor baseline prune .mf/doctor/report.json --out mfdoctor.baseline.json

Defaults: report path .mf/doctor/report.json, output mfdoctor.baseline.json.

#Apply on check, federation, and plugins

Config (mfdoctor.config.ts or plugin options):

export default {
  baseline: "./mfdoctor.baseline.json",
  // or:
  // baseline: { path: "./mfdoctor.baseline.json", failOnSuppressed: false, reportStale: true },
};

CLI:

mfdoctor check --ci --baseline ./mfdoctor.baseline.json
mfdoctor federation ".mf/doctor/**/project.json" --baseline ./mfdoctor.baseline.json

Plugin CI runs use the same DoctorOptions.baseline field:

federationDoctor({
  moduleFederation: mfOptions,
  baseline: "./mfdoctor.baseline.json",
});

#Policy behavior

• Matched findings stay in terminal, JSON, and SARIF reports, marked suppressed: true (SARIF suppressions with kind external).
• By default they do not fail failOn policy.
• Set baseline.failOnSuppressed: true if suppressed findings should still fail the gate.
• Unused baseline fingerprints emit doctor/stale-baseline info findings when reportStale is true (default). Remove those entries — the debt is paid.

#Incremental adoption recipe

1. Enable the MFDoctor plugin and collect a full report with failOn: "never" (or local defaults).
2. mfdoctor baseline generate and commit the file.
3. Turn on CI failOn: "error" (or rely on CI auto-detect).
4. Fix or intentionally baseline only new regressions; prune as you clear debt.
5. Treat a growing baseline as a process smell — shrink it.