/ln-24-architecture-decision-recorder

name: ln-24-architecture-decision-recorder
description: "Records one architecture decision with alternatives, consequences and status; does not design the whole system."

Architecture Decision Recorder

**Goal:** Preserve the context, forces, alternatives, decision, and consequences of one architecturally significant choice in a compact durable record. Change only approved decision documentation; do not design the whole system, approve a decision silently, delete history, audit code, or implement the choice.

**Execution contract:** Track every checklist item as `PENDING`, `PROVEN` with observed outcome evidence, `CLEARED` with evidence its condition is absent, or `UNPROVEN` with a gap. Reading, delegation, tool failure, zero exit status, and self-reported success are not proof. Reconcile after each section; before returning, resolve all `PENDING`, count only `PROVEN` and `CLEARED`, and apply verdict and approval rules to every gap. Preserve intent, scope, mode, and existing authorization. Complete authorized work before required external approval; ask only consequential unresolved choices. If nobody can answer, report the exact question and apply the skill's gap verdict without waiting or guessing. Cite any blocking instruction and unresolved boundary; never invent approval gates. Scale depth to material risk; preserve mandatory checks, dependencies, and safety order while choosing verification methods. Accept equivalent user or repository evidence without requiring another skill, named artifact, or full lifecycle. Preserve source requirement and decision IDs. Bind reused evidence to relevant versions, dirty changes, configuration, environment, and observation windows; invalidate only affected claims. Choose the primary workflow by outcome and explicit selection. Consume neighboring contracts and valid evidence without duplicating ownership or restarting audits. Split distinct deliverables by scope, not mandatory skill invocation. Broad independent assessments use audit workflows; focused domain reviews remain read-only. On continuation, reconcile task, authorization, state, and gaps. Return a compact continuation record for long work or update an already authorized artifact; read-only skills do not persist it. Distinguish artifact readiness, verified behavior, and external-action authority. Trace applicable requirements to their authoritative owner, planned or implemented change, acceptance evidence and status in the existing artifact or response; no new registry is required. Explicit constraints remain binding until an authorized deviation; risk determines priority, not permission to ignore them. Investigate the causal flow beyond initially named files. Within implementation authority, include structural repair needed for the outcome; minimize total complexity and risk, not changed lines. This does not authorize unrelated cleanup or mutation during review. Before retrieval, define the evidence question; read selectively without skipping applicable instructions. Use tools for mechanical processing; summarize bounded results, errors, coverage, and source paths, keeping full output outside context. Before technical decisions, establish applicability and actual versions; verify version-dependent assumptions against official documentation or specifications. Search and read primary pages for current external recommendations; snippets are not evidence. Version-matched bundled documentation or valid prior evidence suffices. Record decision, version, source, and limitations. Mark unavailable evidence UNVERIFIED; block only essential dependent work. Prefer native mechanisms, justify added tools or abstractions with evidence, and reuse the existing rule owner.

Tool Routing

| Need | Preferred capability | Fallback | |---|---|---| | Existing decision convention | Repository search and direct document reads | Use the default path and compact format | | Decision drivers | Requirements, architecture artifacts, implementation evidence, and stakeholder statements | Mark unsupported drivers `UNKNOWN` | | Alternatives and external claims | Repository evidence plus current official sources | Mark time-sensitive claims `UNVERIFIED` | | Sequence and supersession | Existing filenames, indexes, and decision links | Return `BLOCKED` rather than reuse a number | | Document mutation | Minimal patch to one approved decision record and necessary supersession links | Return `BLOCKED` if authority or path is unclear |

One record captures one decision. If the request contains independent decisions with different drivers or lifecycles, split them only with explicit approval.

Workflow Boundary

An ADR owns one accepted or proposed decision and its rationale. Operational procedures and executable configuration remain their own sources of truth; reference them rather than reproducing instructions or mutable registries.

Artifact Rules

• Reuse the repository's established ADR convention when one exists.
• Otherwise use `docs/architecture/decisions/NNNN-<slug>.md` with the next unused monotonic number.
• Never renumber, delete, or rewrite the decision and rationale of historical records. Permit scoped status and supersession-link updates under the rules below; distinguish evolving proposed drafts from accepted history.
• Default a new record to `Proposed`.
• Use `Accepted` only after explicit confirmation from an authorized decision-maker.
• A proposed replacement links to the current decision without changing its effective status. Mark the old record `Superseded` and link both directions only after the replacement is explicitly accepted; preserve historical content.
• Keep the record short enough to review as a single decision.
• Preserve the rationale a future maintainer needs to reconsider it safely.
• Label retrospective records explicitly; do not imply that documentation created after implementation was prior approval.
• Separate evidence needed before acceptance from monitoring required after