feat(bmm): add improve architecture skill

src/bmm-skills/3-solutioning/bmad-architecture/SKILL.md

@@ -1,12 +1,13 @@
 ---
 name: bmad-architecture
-description: 'Produce the architecture: a lean spine of invariants that keeps everything built from it consistent, projected into whatever format the work needs. Use when the user says "create the architecture", "create technical architecture", "architecture spine", or "create a solution design".'
+description: 'Produce, update, validate, or refine architecture as a lean spine of invariants that keeps independently built work consistent. Use when the user asks for architecture, solution design, an architecture spine, or brownfield refinement of seams, interfaces, and module boundaries.'
 ---
+
 # BMad Architecture
 
 ## Overview
 
-You produce an **architecture spine**: a consistency contract that fixes only the **invariants** keeping independently-built units from diverging — the design paradigm, the boundary and dependency rules, how state is mutated, who owns shared data. Everything structural (stack, tree, full data shape) is **seed**: true at cold-start, owned by the code once it exists. A spine is not a design document; its worth is the durable calls a future builder *can't* read off compliant code. Lead with a named paradigm — it carries a whole model for free — and keep the seed minimal.
+You produce an **architecture spine**: a consistency contract that fixes only the **invariants** keeping independently-built units from diverging — the design paradigm, the boundary and dependency rules, how state is mutated, who owns shared data. Everything structural (stack, tree, full data shape) is **seed**: true at cold-start, owned by the code once it exists. A spine is not a design document; its worth is the durable calls a future builder _can't_ read off compliant code. Lead with a named paradigm — it carries a whole model for free — and keep the seed minimal.
 
 One test decides what belongs:
 
@@ -18,17 +19,17 @@ Record decisions, not rationale (rationale lives in the memlog). Carry shape in
 
 ## How you work
 
-You're a coach, and the **Coaching path is the default** — this runs against the model's instinct to just produce an architecture, so hold the line on it. The choice (offered as an Activation step, in the user's language, before any drafting): **Coaching path** (we work it together — open-ended questions, I pull the decisions out of you and push back where one is thin) or **Fast path** (I draft the whole spine fast with `[ASSUMPTION]` tags you correct in review). Unless the user clearly wants speed, **coach; don't silently draft.** A finished architecture produced from two quick questions is the failure mode, not the win — the elicitation is the value. On the Coaching path, the load-bearing calls — paradigm, stack or starter, the major boundaries — are *shown, not silently made*: lay out the realistic alternatives you weighed and why you lean one way, then let the user choose. That rationale lives in the conversation and the memlog, never in the terse spine.
+You're a coach, and the **Coaching path is the default** — this runs against the model's instinct to just produce an architecture, so hold the line on it. The choice (offered as an Activation step, in the user's language, before any drafting): **Coaching path** (we work it together — open-ended questions, I pull the decisions out of you and push back where one is thin) or **Fast path** (I draft the whole spine fast with `[ASSUMPTION]` tags you correct in review). Unless the user clearly wants speed, **coach; don't silently draft.** A finished architecture produced from two quick questions is the failure mode, not the win — the elicitation is the value. On the Coaching path, the load-bearing calls — paradigm, stack or starter, the major boundaries — are _shown, not silently made_: lay out the realistic alternatives you weighed and why you lean one way, then let the user choose. That rationale lives in the conversation and the memlog, never in the terse spine.
 
-Elicit, don't quiz: open-ended "how are you thinking about X?" beats a multiple-choice menu; reserve a crisp either/or for a genuinely binary fork. When you catch yourself picking the boundaries, the stack, or the phases for the user, hand the pen back — unless you're on the Fast path, where inferring and tagging *is* the job.
+Elicit, don't quiz: open-ended "how are you thinking about X?" beats a multiple-choice menu; reserve a crisp either/or for a genuinely binary fork. When you catch yourself picking the boundaries, the stack, or the phases for the user, hand the pen back — unless you're on the Fast path, where inferring and tagging _is_ the job.
 
 When the stack is open — greenfield, or a small/beginner project that could sit on a paved path — **recommend a well-known current starter** (verify the going choice on the web first): a good one pre-decides a coherent slab of the architecture for free and beats hand-rolling for a less-experienced user. For brownfield, **investigate before you decide** — read enough of the real code (and `project-context.md`; if there is none, offer to invoke the `bmad-document-project` skill) to ratify the conventions already there rather than invent new ones.
 
 ## Read the input to know the job
 
-The input itself tells you what kind of job this is — read it rather than quizzing the user about it. A spec package (`SPEC.md` + its memlog) is the richest start and the spine's home, so fold the spine back into it. But you'll also get a raw idea, a sprawling architecture document to distill down, an existing codebase to derive a spine *from* (ratify the conventions the code already shows — don't re-document them), the slice of one a new feature touches, or an existing spine to extend or pressure-test. Prefer a `.memlog.md` over re-reading the source it came from. Distill whatever you're given; mark real gaps as open questions instead of inventing answers. The spine's **altitude** mirrors what it augments and keeps the level below coherent — initiative→features, feature→epics, epic→stories.
+The input itself tells you what kind of job this is — read it rather than quizzing the user about it. A spec package (`SPEC.md` + its memlog) is the richest start and the spine's home, so fold the spine back into it. But you'll also get a raw idea, a sprawling architecture document to distill down, an existing codebase to derive a spine _from_ (ratify the conventions the code already shows — don't re-document them), the slice of one a new feature touches, an existing spine to extend or pressure-test, or a brownfield seam/interface/module-boundary to refine. Prefer a `.memlog.md` over re-reading the source it came from. Distill whatever you're given; mark real gaps as open questions instead of inventing answers. The spine's **altitude** mirrors what it augments and keeps the level below coherent — initiative→features, feature→epics, epic→stories.
 
-**Inheriting a parent spine** (e.g. pointed at one epic of a spec whose feature/initiative spine already exists): load the parent `ARCHITECTURE-SPINE.md` first and treat its `AD`s, conventions, and paradigm as **binding, read-only** constraints — log each as a `constraint` entry, list them under the spine's *Inherited Invariants* (parent `AD` IDs, never renumbered), and don't re-derive them. Your job is only what the parent **left open**: its `Deferred` items plus the divergences this epic's stories could hit. A new `AD` that contradicts or weakens an inherited one is a **conflict to surface**, not a local override. An epic spine fixes the invariants the epic's stories must share — it does **not** expand per-story detail; that's deferred to story time, when you invoke the `bmad-create-story` skill.
+**Inheriting a parent spine** (e.g. pointed at one epic of a spec whose feature/initiative spine already exists): load the parent `ARCHITECTURE-SPINE.md` first and treat its `AD`s, conventions, and paradigm as **binding, read-only** constraints — log each as a `constraint` entry, list them under the spine's _Inherited Invariants_ (parent `AD` IDs, never renumbered), and don't re-derive them. Your job is only what the parent **left open**: its `Deferred` items plus the divergences this epic's stories could hit. A new `AD` that contradicts or weakens an inherited one is a **conflict to surface**, not a local override. An epic spine fixes the invariants the epic's stories must share — it does **not** expand per-story detail; that's deferred to story time, when you invoke the `bmad-create-story` skill.
 
 ## How a run works
 
@@ -53,10 +54,10 @@ Writes go through the shared script (don't read the file back except on resume):
 
 1. Resolve customization: `python3 {project-root}/_bmad/scripts/resolve_customization.py --skill {skill-root} --key workflow` (on failure read `{skill-root}/customize.toml`, use defaults). Run `{workflow.activation_steps_prepend}`, then `{workflow.activation_steps_append}`. Hold `{workflow.persistent_facts}` as standing context — the default loads `project-context.md`, load-bearing for brownfield — and consult `{workflow.external_sources}` on demand.
 2. Load `{project-root}/_bmad/bmm/config.yaml` (+ `config.user.yaml`) for `{user_name}`, `{communication_language}`, `{document_output_language}`, `{planning_artifacts}`, `{project_name}`, `{date}`; missing keys take neutral defaults, never block.
-3. Headless (no interactive user) → follow `references/headless.md` for the whole run. Otherwise greet `{user_name}` in `{communication_language}`. Detect the intent from the conversation and input — **create** (the default), **update** an existing spine, or **validate** one (see those sections). If the real ask is requirements / UX / a capability contract / epic breakdown / an agent, invoke the `bmad-prd`, `bmad-ux`, `bmad-spec`, `bmad-create-epics-and-stories`, or `bmad-workflow-builder` (if the BMad Builder module is installed) skill instead.
+3. Headless (no interactive user) → follow `references/headless.md` for the whole run. Otherwise greet `{user_name}` in `{communication_language}`. Detect the intent from the conversation and input — **create** (the default, including deriving a general spine from a brownfield codebase), **update** when an accepted spine amendment is already known, **validate** a spine without changing it, or **refine** when a specific seam/interface/module boundary/hotspot or tentative amendment must be investigated before acceptance (see those sections). If the real ask is requirements / UX / a capability contract / epic breakdown / an agent, invoke the `bmad-prd`, `bmad-ux`, `bmad-spec`, `bmad-create-epics-and-stories`, or `bmad-workflow-builder` (if the BMad Builder module is installed) skill instead.
 4. If a run folder for this target already exists under `{workflow.spine_output_path}`, offer to resume from its memlog rather than restart.
-5. Interactive create: offer the working mode in `{communication_language}` — **Coaching path** (default) or **Fast path** (see *How you work*) — before any drafting; default to Coaching unless the user asks for speed.
-6. **Mandatory, both paths, before drafting:** ask whether the spine is the only deliverable — and if not, draw out the *purpose and audience* rather than a document type. "An architecture doc" balloons into bloat; what they actually need might be a one-detail explainer for a single team or a non-technical vision piece for a board. Purpose right-sizes the artifact and may call for extra elicitation up front, not just a finale add-on.
+5. Interactive create or refine: offer the working mode in `{communication_language}` — **Coaching path** (default) or **Fast path** (see _How you work_) — before drafting or comparing options; default to Coaching unless the user asks for speed.
+6. **Mandatory, both paths, before drafting:** ask whether the spine is the only deliverable — and if not, draw out the _purpose and audience_ rather than a document type. "An architecture doc" balloons into bloat; what they actually need might be a one-detail explainer for a single team or a non-technical vision piece for a board. Purpose right-sizes the artifact and may call for extra elicitation up front, not just a finale add-on.
 
 For a new spine, bind `{doc_workspace}` to `{workflow.spine_output_path}/{workflow.run_folder_pattern}/`, seed `ARCHITECTURE-SPINE.md` from `{workflow.spine_template}`, run `memlog.py init`, and tell the user the path. **At epic altitude, scope the folder to the epic** (set `run_folder_pattern` per `customize.toml`) so per-epic runs don't collide.
 
@@ -72,11 +73,21 @@ Walk the sequence; reviewer fixes land before polish.
 2. **Reconcile inputs.** A subagent per load-bearing input checks it against the spine and returns what didn't land — especially a quiet requirement (a tone, a constraint) the `AD` structure dropped. Before the gate.
 3. **Reviewer pass.** Run the Reviewer Gate (`references/reviewer-gate.md`). Resolve before polish.
 4. **Triage.** Open questions and `[ASSUMPTION]` tags: blockers (unsafe for what's next) resolved one at a time; the rest deferred with a revisit condition in the memlog.
-5. **Renderings & polish.** The spine is the build deliverable; with it and the memlog now in place, produce any *additional* human-facing artifact the user needs, scoped to the purpose and audience drawn out up front. The up-front question already flagged whether one's needed; if it wasn't, still offer one here, seeding concrete options: an interactive HTML+SVG deck to walk a team through the architecture and drive discussion, a fuller HTML/md solution design, a C4 set, or a view of how the work splits across teams/epics. Build only what they pick, right-sized to that purpose; apply `{workflow.doc_standards}` polish to that prose only, never to the spine.
+5. **Renderings & polish.** The spine is the build deliverable; with it and the memlog now in place, produce any _additional_ human-facing artifact the user needs, scoped to the purpose and audience drawn out up front. The up-front question already flagged whether one's needed; if it wasn't, still offer one here, seeding concrete options: an interactive HTML+SVG deck to walk a team through the architecture and drive discussion, a fuller HTML/md solution design, a C4 set, or a view of how the work splits across teams/epics. Build only what they pick, right-sized to that purpose; apply `{workflow.doc_standards}` polish to that prose only, never to the spine.
 6. **External handoffs.** Run `{workflow.external_handoffs}`; surface returned URLs/IDs. Offer to invoke the `bmad-spec` skill to adopt the spine as a companion, keeping `AD` IDs stable so downstream can cite them.
 7. **Close.** Set the spine's own frontmatter `status: final`, `updated: {date}`; log a `memlog.py append --type event --text "spine finalized"` (the memlog has no status field). Share paths. Next, **lead with `bmad-spec`** — recommend adopting/refreshing the spine as a spec companion (always the top recommendation when a spec was an input, and a useful next step even when it wasn't), then `bmad-create-epics-and-stories` or — epic altitude — `bmad-create-story`; or invoke `bmad-help` to route.
 8. Run `{workflow.on_complete}`.
 
+## Refine
+
+Investigate a brownfield hotspot or pressure-test a seam, interface, or module boundary when the desired amendment is not yet known. Load `references/architecture-refinement.md`; when interface shape is at issue, also load `references/interface-design.md`.
+
+Use the normal run workspace and memlog. Select the nearest governing spine at the target altitude and inherit any parent spine above it. If that spine exists, resume from its `.memlog.md`; when its memlog is missing, reconstruct only demonstrable constraints from the spine and code, mark the reconstruction as an assumption, and halt blocked if stable decision history cannot be preserved. If no spine applies, perform the normal new-spine initialization (`doc_workspace`, spine template, and `memlog.py init`) at the smallest scope needed for the refinement. Candidate lists, interface comparisons, and recommendations are optional **companions** in `{doc_workspace}` — useful working evidence, never a second architecture authority.
+
+Explore and compare before committing. Existing reality may ratify a constraint or already-adopted decision; a new amendment requires explicit user acceptance in interactive runs. Append the durable outcome to the memlog as a decision, constraint, or deferred item, keeping inherited and existing `AD` IDs stable, then re-distill and run Finalize without changing intent or workspace mid-run. If investigation finds no architecture decision worth binding, record that result as an event; when this run initialized a new spine solely for refinement, remove the unfinalized seed spine and return the companions as non-authoritative evidence rather than manufacturing an `AD`.
+
+Story slices and test strategy are lower-altitude follow-ons: offer them only at epic altitude or when the user explicitly needs implementation planning. They must cite the governing `AD` IDs and remain subordinate to the spine.
+
 ## Update
 
 Amend an existing spine. Resume from its `.memlog.md` (the authority on what was decided), not the rendered spine. Capture the change as new memlog entries; **keep `AD` IDs stable** — amend a Rule in place, add the next `AD-n` for a new decision, never renumber or reuse a retired ID. Then re-distill (Finalize step 1), run the Reviewer Gate (`references/reviewer-gate.md`), and close as in Finalize. An update that overrides something from a source input: offer to update that source too, so upstream and the spine don't silently diverge.