{"record":{"id":"39f50a685529f722","repo":"JuliusBrussee/caveman","slug":"where-causal-slice-is-not-taken-from-the-baseli","errorCode":null,"errorMessage":"${where} causal slice is not taken from the baseline arm's variant","messagePattern":"(.+?) causal slice is not taken from the baseline arm's variant","errorType":"exception","errorClass":"Error","httpStatus":null,"severity":"error","filePath":"packages/shared/contracts/scripts/validate-continuous-improvement.mjs","lineNumber":174,"sourceCode":"    }\n\n    const selectedPerArm = new Map();\n    for (const trace of item.representative_traces) {\n      const variant = armVariants.get(trace.arm);\n      if (!variant || variant.id !== trace.variant_id) throw new Error(`${where} representative trace names a variant that is not that arm's variant`);\n      if (!unitsByID.has(trace.analysis_unit_id)) throw new Error(`${where} representative trace ${trace.analysis_unit_id} is not an analysis unit of this report`);\n      if (!familyUnits.has(trace.analysis_unit_id)) throw new Error(`${where} representative trace ${trace.analysis_unit_id} is not a member of the cohort's task family`);\n      if (!variant.analysis_unit_ids.includes(trace.analysis_unit_id)) throw new Error(`${where} representative trace ${trace.analysis_unit_id} did not run that arm's workflow variant`);\n      selectedPerArm.set(trace.arm, (selectedPerArm.get(trace.arm) ?? 0) + 1);\n    }\n    for (const [arm, count] of selectedPerArm) {\n      if (count > 3) throw new Error(`${where} arm ${arm} carries ${count} representative traces, more than three`);\n    }\n\n    const slice = item.causal_slice;\n    const sliceVariant = variantsByID.get(slice.variant_id);\n    if (!sliceVariant) throw new Error(`${where} causal slice references a workflow variant that is not in this report`);\n    if (sliceVariant.id !== armVariants.get(\"baseline\").id) throw new Error(`${where} causal slice is not taken from the baseline arm's variant`);\n    const sliceNodes = new Set(sliceVariant.nodes.map((node) => node.id));\n    if (slice.manifestation_node_id !== \"\" && !sliceNodes.has(slice.manifestation_node_id)) {\n      throw new Error(`${where} manifestation node ${slice.manifestation_node_id} is not a node of variant ${sliceVariant.id}`);\n    }\n    if (item.diagnosis.manifestation.node_id !== slice.manifestation_node_id) {\n      throw new Error(`${where} diagnosis manifestation node disagrees with its causal slice`);\n    }\n    for (const nodeID of slice.node_chain) {\n      if (!sliceNodes.has(nodeID)) throw new Error(`${where} causal slice node ${nodeID} is not a node of variant ${sliceVariant.id}`);\n    }\n    if (slice.manifestation_node_id !== \"\" && !slice.node_chain.includes(slice.manifestation_node_id)) {\n      throw new Error(`${where} causal slice omits its own manifestation node`);\n    }\n    const provenDependency = (edge) => edge.strength === \"hard\" && (edge.type === \"data\" || edge.type === \"control\") && edge.evidence_refs.length > 0;\n    const variantEdges = new Map(sliceVariant.edges.map((edge) => [`${edge.from}\u0000${edge.to}\u0000${edge.type}`, edge]));\n    for (const edge of slice.hard_edges) {\n      if (!provenDependency(edge)) throw new Error(`${where} hard chain carries an unproven edge ${edge.from}->${edge.to}`);\n      if (!sliceNodes.has(edge.from) || !sliceNodes.has(edge.to)) throw new Error(`${where} hard chain edge ${edge.from}->${edge.to} names a node outside variant ${sliceVariant.id}`);","sourceCodeStart":156,"sourceCodeEnd":192,"githubUrl":"https://github.com/JuliusBrussee/caveman/blob/766dce6b1394ebb56a3090748d5a0240a5aefb36/packages/shared/contracts/scripts/validate-continuous-improvement.mjs#L156-L192","documentation":"The causal slice must be taken from the baseline arm's variant: the resolved slice variant's id must equal armVariants.get('baseline').id (validate-continuous-improvement.mjs:174). The slice explains where the investigated failure manifests in the current (baseline) workflow; slicing the alternative variant would explain a workflow that was not the subject of the diagnosis.","triggerScenarios":"causal_slice.variant_id points at the alternative variant; the arms were swapped (error 604) so 'baseline' now resolves to the other variant; the slice block was cloned from a case with a different baseline.","commonSituations":"Building the slice from the 'interesting' new variant instead of the current one; refactors that reorder arms; copy-paste between cases in multi-variant fixtures.","solutions":["Point causal_slice.variant_id at whatever variant the baseline arm names.","Fix arm ordering first if error 604 also fires — it changes which variant 'baseline' resolves to.","Re-run the validator; node and edge checks (615-619) run against the corrected slice."],"exampleFix":"// before — baseline arm uses wf-build-01\n\"causal_slice\": { \"variant_id\": \"wf-build-02\", ... }\n// after\n\"causal_slice\": { \"variant_id\": \"wf-build-01\", ... }","handlingStrategy":"validation","validationCode":"const nonBaselineSlices = (report) =>\n  report.cases.filter((c) => {\n    const baseline = c.cohort.arms.find((a) => a.role === 'baseline');\n    return c.causal_slice.variant_id !== baseline?.variant_id;\n  }).map((c) => c.id);","typeGuard":null,"tryCatchPattern":"try {\n  execFileSync(process.execPath, [VALIDATOR, reportPath, spansPath]);\n} catch (err) {\n  if (/not taken from the baseline/.test(err.message)) {\n    failCI(`slice must come from the baseline arm's variant: ${err.message}`);\n  } else throw err;\n}","preventionTips":["Always slice the current (baseline) workflow, even when the alternative is more interesting.","Fix arm ordering (error 604) before debugging slice checks.","Compute slice.variant_id from the baseline arm lookup so it cannot drift."],"tags":["fixtures","cross-validation","causal-slice","baseline","cross-field"],"backgroundTag":"cross-field-mismatch","analyzedSha":"766dce6b1394ebb56a3090748d5a0240a5aefb36","analyzedAt":"2026-08-18T03:14:35.516Z","contentChangedAt":"2026-08-18T03:14:35.516Z","schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}