architectural-decision-record

# Create ADR

## Operating Principles

- **YAGNI applies to ADRs themselves.** Apply the evidence-based YAGNI rule from
  [../../references/yagni-rule.md](../../references/yagni-rule.md). An ADR is worth recording only when there is a
  concrete forcing function today — a real decision the team is actively making, an existing code path or architectural
  choice that will be locked in by this record, an applicable regulation, a customer commitment, or a documented
  incident that drove the choice. ADRs about decisions that don't have to be made yet, "for future flexibility", "best
  practice says we should pick X", or symmetry with other ADRs ("we have one for auth, so we should have one for
  billing") are YAGNI candidates and the ADR should not be written. When proposed, recommend deferral with the trigger
  that would justify writing the ADR (a real decision arising, a real incident, a real regulation taking effect). The
  user always wins; the rule's job is to make the cost of writing speculative architectural records visible — every ADR
  is a future-reader's load and a pattern future agents will treat as committed.
- **The companion evidence rule applies to the ADR's supporting evidence.** Apply the evidence rule from
  [../../references/evidence-rule.md](../../references/evidence-rule.md) to the citations that justify the ADR's
  decision and rejected alternatives. Name the trust class of each citation (codebase, web, provided); mark
  single-source web claims that drive the chosen option; and when no evidence at any tier supports a claimed trade-off,
  label it rather than presenting it as a weak preference.
- **The readability rule shapes the ADR's prose.** Source the standard by invoking
  `han-communication:readability-guidance` and apply it as you write the ADR. Hold its default audience frame: a capable
  reader who did not make this decision and lacks your context. The frame governs how each section reads, never whether
  a required technical fact appears.

## Project Context

- CLAUDE.md: !`find . -maxdepth 1 -name "CLAUDE.md" -type f`
- project-discovery.md: !`find . -maxdepth 3 -name "project-discovery.md" -type f`
- personal config directory: !`bash "${CLAUDE_PLUGIN_ROOT}/scripts/han-config-dir.sh" 2>/dev/null || echo "$HOME/.claude"`
- project .han/config.md: !`cat .han/config.md 2>/dev/null || echo ""`

As your first action, use the Read tool on `.han/config.md` inside the `personal config directory` path above. A read
that returns no file is no personal configuration: continue silently. When that file or the `project .han/config.md`
probe supplies content, apply it per [config-rule.md](../../references/config-rule.md), which governs precedence
between the two files, relative-path resolution, and what to do with a file that reads but cannot be used.

## Step 1: Determine Mode

Determine which mode to operate in based on the user's request:

| Mode                | When                                                                 | Initial Status | Then                            |
| ------------------- | -------------------------------------------------------------------- | -------------- | ------------------------------- |
| Creating new        | Building an ADR from scratch for a new or recent decision            | `proposed`     | → Step 2                        |
| Converting existing | User provides an existing document to convert into an ADR            | `accepted`     | → Step 2                        |
| Updating existing   | Modifying an existing ADR (status change, superseding, adding notes) | —              | Read the existing ADR, → Step 3 |

## Step 2: Discover Project Structure

1. **Retrieve project config:** Resolve project config: read CLAUDE.md's `## Project Discovery` section for docs and ADR
   directories; fall back to project-discovery.md; fall back to Glob defaults (`docs/`, `docs/adr/`). Continue without
   any keys that remain unfound.

2. **Determine the ADR directory:** Use the ADR directory if found; otherwise use `{docs-dir}/adr/` if a docs directory
   was found; otherwise use `docs/adr/`. Run `mkdir -p` on the resolved directory to ensure it exists.

3. **Enumerate existing ADRs:** Use Glob to find existing `.md` files in the ADR directory.

4. **Check existing ADR format:** If existing ADRs were found, read one to understand the project's format. If it
   differs from [template.md](./references/template.md), ask the user whether to match the existing format or use this
   skill's template.

5. **Discover the filename hierarchy taxonomy:** ADRs are organized by a one- or two-level hierarchy encoded in the
   filename so related decisions sort together in a directory listing. Discover the taxonomy that applies to _this_
   project — never hardcode it.
   - **From existing filenames:** If existing ADRs were enumerated, parse their filenames to extract the leading
     hierarchy segments already in use (e.g., `auth-session-storage.md` → top-level `auth`; `auth-tokens-rotation.md` →
     top-level `auth`, second-level `tokens`). Build a list of top-level prefixes and known second-level prefixes per
     top-level.
   - **From project context:** Read CLAUDE.md and project-discovery.md (paths from project context above) to identify
     the project's languages, frameworks, runtimes, subsystems, and bounded contexts. Each is a candidate top-level
     hierarchy (e.g., `auth`, `billing`, `api`, `worker`, `postgres`, `terraform`).
   - **Carry forward to Step 4:** the discovered top-level prefixes (existing + candidate) and any second-level prefixes
     already in use under each.

## Step 3: Gather Context

1. From the arguments and conversation, determine:
   - **Topic/title** — What is the ADR about?
   - **Decision** — What was decided and why?
   - **Alternatives** — What other options were considered?
   - **Forcing function** — What concrete trigger requires this decision _now_? Per
     [../../references/yagni-rule.md](../../references