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type: adr id: 0031-source-authority-two-axis status: accepted created: 2026-06-02 updated: 2026-06-02 supersedes: superseded_by:

ADR-0031: The source-authority two-axis model

Context

When two artifacts assert conflicting obligations — they constrain the same trigger, state, or surface with incompatible modality — something must decide which one governs. Absent a decision procedure, the only operative rule is the implicit one: the most recently written artifact silently wins. That lets a casual chat remark override an accepted decision, and an observation-only audit override an approved spec, without any recorded authoring act (§22).

A single precedence ladder is also insufficient. Two genuinely independent questions are in play: "how settled is the container an obligation was traced back from" and "how much governing force does its domain project downstream." A security obligation and a product obligation can sit in artifacts of equal rank yet must not share governing force. Collapsing both questions into one ordering would force a false ranking between them (§22, §22.1).

Decision

Authority is resolved on two orthogonal axes, applied lexicographically — domain first, then artifact — as detailed in the source-authority reference ().

• Axis A — artifact authority (backward trace): ranks an obligation by the kind and lifecycle status of the artifact containing it (accepted adr.md highest, down through approved spec, accepted finding, reviewed audit/research, task notes, to chat lowest) (§22.1.1).
• Axis B — domain authority (forward governing force): ranks an obligation by its governance domain (enforced-policy highest, down through compliance, security, architecture, product, team, task-map, to memory lowest), discoverable deterministically from a DOMAIN clause, the spec's frontmatter domain, or the default product (§22.1.2).

The conflict rule combines them with a hard-policy gate (§22.2): domain rank (Axis B) is decisive only when at least one obligation is in the hard-policy band (ranks 1–3) and lives in a durable, reviewed artifact; otherwise artifact authority (Axis A) is the most-significant key and domain rank only breaks ties. If both axes are equal, a conformant tool MUST stop and emit SOL-M002, routing the conflict to amendment — resolution is an authoring act, never an inference. This is a deterministic comparison over the typed obligation set, not a runtime: the contract requires a conformant tool to honour the ordering; nothing "runs" it.

Alternatives considered

Alternative	Why rejected
Let the most recently written artifact win (implicit status quo)	The exact failure §22 exists to prevent — chat or an un-reviewed note silently amends an accepted ADR with no recorded authoring act.
One flat precedence ladder collapsing domain and artifact	The two questions are genuinely independent; a single ladder forces a false ranking and would let an equal-artifact security and product obligation share governing force (§22, §22.1).
Domain rank decisive everywhere (Axis B always dominates)	Would let a low-criticality domain note (e.g. a team remark in a reviewed audit) override a higher-authority artifact (a product obligation in an approved spec); the hard-policy gate confines domain-dominance to ranks 1–3 (§22.2).
Auto-select a winner when both axes tie	Resolution is an authoring act, not an inference; a tie is a genuine contradiction (SOL-M002) that MUST route to review (§22.2 step 3).
Treat every source as equally bindable (flat retrieval)	Authority is the conflict-resolution complement to the obligation graph; flat retrieval has no answer to "which wins" and rests provenance on recency (§22).

Consequences

Positive

• Conflicts resolve deterministically and provenance-aware: a hard-policy obligation governs by domain even from a lower-ranked artifact, while below that band the settled-ness of the container decides.
• The two axes double as bidirectional traceability — Axis A is the backward trace to provenance, Axis B is the forward governing force over what an obligation rules (§22.5).
• A genuine contradiction surfaces as SOL-M002 and routes to amendment rather than being silently swallowed (§22.2).

Negative

• Authors must classify each obligation's domain, and the hard-policy gate adds a band check before the lexicographic compare — more procedure than a single ladder.
• The full rule (gate + two axes + invariants) is more to teach than "most recent wins," and demands the source-authority reference doc state both axes, the rule, the invariants, and the worked tie-break (§22.5).

Neutral / tradeoffs

• memory and task-map are axis floors: a promoted finding can inform but never weaken an obligation. Promotion to a spec carries the new container's authority — intent acquiring rank, not the floor being breached (§22.4).
• An obligation below approved/accepted status occupies its draft tier, one rank below its accepted tier (§22.1.1) — a precedence detail authors must track during a migration.

Status

Accepted (v0.1).

Affected obligations / constraints

• Adds: the two-axis source-authority procedure — Axis A (artifact), Axis B (domain), the lexicographic rule with hard-policy gate, the three cross-axis invariants, and the SOL-M002 tie-stop (§22).
• Modifies: the SOL-M004 authority-conflict diagnostic, now defined as a lower-ranked artifact silently amending a higher-ranked one under this model (§22.1.1).
• Supersedes: none.