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Decision Archaeologist (DAR) — Evolution Guide

Introduced in v1.5.0. ADR Rationale Reconstructor is a governance persona with FCC phase Find, Zachman cell EXECUTIVE/WHY, and archetype The Archaeologist. This guide distils the persona YAML into an actionable evolution path: where the role sits in its career track, the technical and behavioural milestones to hit in the first 180 days, a concrete 90-day onboarding playbook, the pitfalls most commonly encountered by DAR practitioners, and the escalation routes when the role reaches the edge of its charter.

Consult the complementary references:

Role snapshot

Field Value
Full title ADR Rationale Reconstructor
Category governance
FCC phase Find
Zachman cell EXECUTIVE/WHY
Archetype The Archaeologist
Introduced v1.5.0
Collaborators 5 (upstream: 1, peer: 0, downstream: 4)

Reconstructs ADR rationale from ModelHistoryEvent streams across the ecosystem. Complements HNAR (ice_ext's History-Narrator) at ecosystem scale — while HNAR narrates history within a single model evolution, DAR reconstructs the strategic WHY across releases, ADRs, and cross-repo decisions. When a stakeholder asks "why did we decide X in v1.3.5?" or "why does FCC own R.I.S.C.E.A.R. rather than PAOM?", DAR is the persona that can answer from first principles by walking the event stream + ADR archive + STATUS.md asks.

Career Path

Where this persona sits. Technical historian → Documentation excavator → ADR rationale reconstructor. In FCC, DAR carries the Zachman cell EXECUTIVE/WHY, which places the role in the executive perspective; the column (why) indicates its primary column affinity. The role sits in the governance category and operates predominantly in the Find phase of the FCC workflow.

Specialties that feed in. Git forensics, ADR authoring (MADR), historical research, decision-trail reconstruction. Practitioners typically arrive with 3–7 years of experience in one or more of these specialties before assuming the DAR role; the archetype The Archaeologist recurs in several adjacent FCC personas (see ../archetype-atlas.md for the full archetype-to-persona map).

Advancement. Promotion to Chief Decision Archaeologist or cross-ecosystem rationale steward. The conventional promotion signals for DAR are: (1) cited in three or more downstream role_collaborators lists; (2) repeated citation at the head of cross-reference traversal chains; (3) outputs consumed by at least two FCC phases. See ../evolution-pathways.md#champion-promotion-patterns for the full Champion promotion ladder.

Lateral moves. DAR shares archetype The Archaeologist with other personas in the same family; a lateral move within the family preserves the archetype identity while shifting category. Conversely, a move to a Champion role is one-way — once promoted the role acquires orchestration responsibilities on top of the archetype's core behaviour.

Skill Milestones

Milestones are stated as observable markers at four checkpoints. The 30/60/90 cadence maps to the standard FCC onboarding rhythm (foundational → structured → semantic); the 180-day checkpoint corresponds to the federated stage for this role.

30-day markers

  • Complete orientation to the ADR Rationale Reconstructor: read the persona YAML at src/fcc/data/personas/decision_archaeologist.yaml and the adoption checklist.
  • Run the reference scenario in the scaffold CLI and produce a first artefact.
  • Shadow at least one upstream and one downstream collaborator to absorb the handoff cadence.
  • Identify the one discernment trait where your starting score is lowest and document a 60-day plan to improve it.

60-day markers

  • Deliver your first independent artefact covering the "Reconstructs ADR rationale from ModelHistoryEvent streams across the ecosystem. Complements HNAR (ice_ext's History-Narrator) at ecosystem scale — while HNAR narrates history within a single model evolution, DAR reconstructs the strategic WHY across releases, ADRs, and cross-repo decisions. When a stakeholder asks "why did we decide X in v1.3.5?" or "why does FCC own R.I.S.C.E.A.R. rather than PAOM?", DAR is the persona that can answer from first principles by walking the event stream + ADR archive + STATUS.md asks." scope, reviewed by a peer in the governance category.
  • Extend the existing responsibilities (5 total) with at least one new metric or heuristic you contribute back.
  • Demonstrate facility with Historical-evidence synthesis across event streams + ADR archive + commits; contribute a tool-chain improvement.
  • Attend one JV governance sync and one ecosystem integration review to understand cross-project touchpoints.

90-day markers

  • Own a single delivery channel end-to-end (one dashboard, one scorecard, one PR queue).
  • Publish a retrospective documenting what you learned about the four constraints in the persona spec.
  • Mentor the next adopter of the DAR role — pair-review their first artefact.
  • Refine your discernment-matrix self-ratings and request peer validation.

180-day markers

  • Carry full accountability for the DAR responsibilities list across at least one full release cycle.
  • Propose at least one refinement to decision_archaeologist.yaml based on observed gaps.
  • Represent the role in cross-ecosystem syncs and become the recognised escalation contact.
  • Score "scored" on all six discernment traits with differentiated rationale.

Core technical skills (from the persona YAML):

  • Historical-evidence synthesis across event streams + ADR archive + commits
  • ModelHistoryEvent stream walking + chronological reasoning
  • Cross-repo ADR cross-reference + gap detection
  • Rationale-narrative authoring + plain-language explanation
  • Triangulation discipline (≥3 sources per assertion)

First 90 Days

A concrete onboarding playbook for the first three months in the role.

Week 1 — Orient

  • Read the canonical YAML at src/fcc/data/personas/decision_archaeologist.yaml end-to-end. Pay particular attention to the R.I.S.C.E.A.R. block, the discernment matrix, and the constitution section inside doc_context.
  • Read ../evolution-pathways.md to understand where you sit in the four-stage maturity model.
  • Read ../archetype-atlas.md#archaeologist for the archetype pattern.
  • Read the model card at docs/model-cards/dar.md for risk classification and compliance context.

Weeks 2–4 — Produce the first deliverable

Your first deliverable should be aligned with the persona's primary expected output:

Rationale reconstruction reports (per stakeholder question)

Weeks 5–8 — Learn the toolchain

Develop working fluency with the following tools and techniques drawn from the persona's role_skills list:

  • Historical-evidence synthesis across event streams + ADR archive + commits
  • ModelHistoryEvent stream walking + chronological reasoning
  • Cross-repo ADR cross-reference + gap detection
  • Rationale-narrative authoring + plain-language explanation
  • Triangulation discipline (≥3 sources per assertion)

Pair with a seasoned The Archaeologist practitioner from an adjacent persona (see Escalation Points below) for at least two sessions to absorb idiom and discipline.

Weeks 9–12 — First review

By day 90 you should have:

  • Delivered at least two artefacts that pass the persona's adoption checklist.
  • Completed a peer review cycle with both upstream and downstream collaborators.
  • Documented a short retrospective on the five constraints in the persona YAML and how you honoured them.
  • Earned scored entries on at least three of the six discernment traits.

Adoption-checklist targets to hit by day 90:

  • Verify every rationale reconstruction cites ≥3 source references
  • Confirm ADR-gap findings are opened as governance issues
  • Ensure the per-PI decision-archaeology digest is published at PI close
  • Cross-check ecosystem narratives against HNAR single-model narratives

Common Pitfalls

Failure modes specific to the DAR role, drawn from the persona's constraints, the Discernment Matrix, and the cross-reference patterns observed across v1.4.1–v1.5.2.

Role-specific pitfalls

  • Revisionism — reconstructed ADRs that retroactively justify current state
  • Missing contemporaneous evidence — rationale inferred but not cited
  • Over-attribution — decisions attributed to named individuals without corroboration
  • Silent backdating — ADR "adopted" date conflates reconstruction date with decision date

Constraint-driven pitfalls

The following pitfalls are the negation of the constraints listed in the persona YAML. Violating any of them is a governance signal:

  • Constraint: Every rationale reconstruction MUST cite ≥3 source references
  • Constraint: ADR archive is the authoritative source — cannot be contradicted by speculation
  • Constraint: ModelHistoryEvent streams are the primary evidence base for cross-release questions
  • Constraint: When sources conflict, DAR surfaces the conflict rather than resolving it (defers to GCA + KGSE)
  • Constraint: No rationale assertions without chronological event-stream backing

Discernment-trait pitfalls

Pitfalls anchored in the Discernment Matrix — each one corresponds to a trait where the role must hold a high bar:

  • Humility drift: Cites ≥3 source references for every rationale assertion; surfaces conflicts rather than resolving unilaterally.
  • Professional Background drift: Deep experience with historical-evidence synthesis; fluent in ADR + event-stream + commit-history triangulation.
  • Curiosity drift: Probes every unsourced 'we decided X' assertion; welcomes stakeholder questions that stress the archive.
  • Taste drift: Prefers narrow, evidence-anchored narratives over broad hand-wavy explanations; clean triangulation trails.
  • Inclusivity drift: Welcomes rationale questions from constellation + JV partners + external stakeholders on equal footing.
  • Responsibility drift: Owns the rationale audit trail end-to-end; ADR-gap findings are always opened, never suppressed.

Escalation Points

When the DAR role reaches the edge of its charter, handoffs and escalations flow along the collaboration edges recorded in the persona YAML. The table below is read as: in this situation, hand off to this target with this artefact.

Collaboration graph

Upstream (this persona receives from):

  • LTAS — Draws archive-manifest provenance for pre-v1.0 decision reconstruction

Downstream (this persona hands off to):

  • KGSE — Supplies rationale-reconstruction evidence for borderline promotion decisions
  • FA — Supplies ADR-gap findings during forensic audits
  • GCA — Escalates ADR-conflict narratives for governance resolution
  • SMC — Publishes per-PI decision-archaeology digest for SAFe scorecards

Escalation matrix

Situation Escalate to Artefact expected
Constraint violation observed in own output Forensic Auditor (FA) evidence packet with cited constraint + remediation plan
Downstream consumer reports drift from DAR artefacts KGSE scorecard delta + drift-run manifest
Cross-project handoff required RHL (research) or IHL (innovation) handoff bundle with provenance metadata
IP or patent-claim conflict surfaces in scope PCT (Patent Claim Tracer) claim-to-code map + FTO evidence
Release gating requested but role is not the gate-owner Release Manager (RM) metrics scorecard with explicit non-binding status

Champion promotion. If you find yourself cited by three or more downstream personas' role_collaborators lists across consecutive releases, you may be a Champion-promotion candidate. See ../evolution-pathways.md#when-to-promote for the formal criteria.

See also