@@ -10,12 +10,12 @@ Guidance for AI agents (Claude Code, etc.) working in this repository.
 
 - [`architecture/`](architecture/) (repo root) — the per-capability living truth, one file per capability ([`architecture/README.md`](architecture/README.md) is the index). The promotion target on every ship. **Read the relevant file before changing that capability.**
 - [`planning/README.md`](planning/README.md) — the planning convention (Quick path + the two-axis convention) and the generated change Index.
-- [`planning/changes/<YYYY-MM-DD.NN-slug>/`](planning/changes/) — per-change bundles (`design.md` + `plan.md`, or `change.md` for the lightweight lane).
+- [`planning/changes/<YYYY-MM-DD.NN-slug>.md`](planning/changes/) — flat change files, one per change (design template for the full lane, change template for the lightweight lane).
 - [`planning/decisions/`](planning/decisions/), [`planning/audits/`](planning/audits/), [`planning/retros/`](planning/retros/), [`planning/releases/`](planning/releases/), [`planning/deferred.md`](planning/deferred.md) — decisions, findings sweeps, retrospectives, release notes, and deferred items.
 
 ## Workflow
 
-Planning follows the portable two-axis convention — `architecture/` (repo root) is the living **truth home** and promotion target; `planning/changes/` holds the per-change bundles. **Start at the [Quick path](planning/README.md#quick-path-start-here)** in `planning/README.md` to choose a lane (Full / Lightweight / Tiny), create a bundle, and ship — that file is the authoritative spec. Run `just check-planning` to validate bundles and `just index` to print the change listing.
+Planning follows the portable two-axis convention — `architecture/` (repo root) is the living **truth home** and promotion target; `planning/changes/` holds the flat change files. **Start at the [Quick path](planning/README.md#quick-path-start-here)** in `planning/README.md` to choose a lane (Full / Lightweight / Tiny), create a change file, and ship — that file is the authoritative spec. Run `just check-planning` to validate changes and `just index` to print the change listing.
 
 ## Commands
 
 
@@ -21,7 +21,7 @@ lint-ci:
 index:
     uv run python planning/index.py
 
-# Validate planning bundles + decisions; CI runs this via lint-ci.
+# Validate planning changes + decisions; CI runs this via lint-ci.
 check-planning:
     uv run python planning/index.py --check
 
 
@@ -1 +1 @@
-1.0.0
+2.0.0
@@ -12,25 +12,22 @@ the repo root; this directory records *how it got there*.
 **1. Choose a lane — first matching rule wins:**
 
 1. Any of: needs design judgment · new file/module · public-API change ·
-   cross-cutting or multi-file · non-trivial test design → **Full**
-   (`design.md` + `plan.md`)
+   cross-cutting or multi-file · non-trivial test design → **Full** (design template)
 2. Purely mechanical: typo · dep bump · linter/formatter/CI tweak ·
-   mechanical rename · single-line config → **Tiny** (no bundle, conventional
+   mechanical rename · single-line config → **Tiny** (no change file, conventional
    commit)
 3. Small-but-real, none of the above: ≲30 LOC net · ≤2 files · no new file ·
-   no public-API change · one straightforward test → **Lightweight**
-   (`change.md`)
+   no public-API change · one straightforward test → **Lightweight** (change template)
 
-Ambiguous between two? Take the heavier. A `change.md` that outgrows its lane
-splits into `design.md` + `plan.md`.
+Ambiguous between two? Take the heavier. A lightweight change file that outgrows its lane is rewritten from the design template.
 
-**2. Create the bundle** (Full / Lightweight only):
-`planning/changes/YYYY-MM-DD.NN-<slug>/`, where `.NN` is a zero-padded
-intra-day counter. Copy the matching template from
+**2. Create the change file** (Full / Lightweight only):
+`planning/changes/YYYY-MM-DD.NN-<slug>.md`, where `.NN` is a zero-padded
+intra-day counter — copied from the matching template (design or change) in
 [`_templates/`](_templates/).
 
 **3. Ship in the implementing PR:** hand-edit the affected
-`architecture/<capability>.md`, finalize the bundle's `summary:` to the
+`architecture/<capability>.md`, finalize the change file's `summary:` to the
 realized result, and run `just check-planning` before pushing.
 
 ## Conventions
@@ -43,20 +40,41 @@ realized result, and run `just check-planning` before pushing.
 
 ### Two axes, never mixed
 
-- **`architecture/` (repo root) — the present.** One file per capability,
-  living prose, updated in the same PR that ships the change. The truth home.
-- **`planning/changes/` — the past-and-pending.** One folder per change,
+- **`architecture/` (repo root) — the present.** One file per capability, plus
+  a single `glossary.md` (the ubiquitous language); living prose, updated in the
+  same PR that ships the change. The truth home.
+- **`planning/changes/` — the past-and-pending.** One file per change,
   kept in place after ship.
 
 A change **promotes** its conclusions into the affected
 `architecture/<capability>.md` by hand **in the implementing PR, alongside the
 code** — the edit rides in the same diff and is reviewed with it, never applied
 as a separate post-merge step. That hand-edit is what keeps `architecture/`
-true; the bundle stays in `changes/` as the *why*.
+true; the change file stays in `changes/` as the *why*.
 
-### Change bundles
+### Glossary
 
-A change is a folder `changes/YYYY-MM-DD.NN-<slug>/`:
+`architecture/glossary.md` is the project's **ubiquitous language** — one page
+defining the domain terms that code, specs, and capability pages all share. Like
+the capability files beside it, it is living prose with **no frontmatter**, dated
+by git, and authored lazily: it appears when the first term is worth pinning down.
+
+Each entry is a term, a one-or-two-sentence definition of what it *is* (not what
+it does), and an optional `_Avoid_:` line naming the synonyms to reject:
+
+```md
+**Timer**:
+A scheduled future delivery, identified by a timer id.
+_Avoid_: job, task, alarm
+```
+
+Keep it a glossary, not a spec — no implementation detail. A change that
+introduces or sharpens a term updates `glossary.md` in the same PR, the same way
+a behavior change promotes into a capability file.
+
+### Change files
+
+A change is a file `changes/YYYY-MM-DD.NN-<slug>.md`:
 
 - `YYYY-MM-DD` — proposal date; `.NN` — zero-padded intra-day counter
   (`.01`, `.02`, …) that breaks same-date ties so the timeline sorts stably.
@@ -65,25 +83,44 @@ A change is a folder `changes/YYYY-MM-DD.NN-<slug>/`:
 `summary` is written when the change is created (the intent one-liner) and
 **finalized at ship** to state the realized result — set in the implementing
 PR, alongside the code and the `architecture/` promotion. No post-merge
-bookkeeping, no folder move. `date` and `slug` are never written — they are
-read from the bundle's directory name.
+bookkeeping, no file move. `date` and `slug` are never written — they are
+read from the file name.
 
 ### Three lanes
 
 | Lane | Artifacts | Use when |
 |------|-----------|----------|
-| **Full** | `design.md` + `plan.md` | design judgment; new file/module; public-API change; cross-cutting/multi-file; non-trivial test design |
-| **Lightweight** | `change.md` | small-but-real: ≲30 LOC net, ≤2 files, no new file, no public-API change, single straightforward test |
+| **Full** | one change file from the design template | design judgment; new file/module; public-API change; cross-cutting/multi-file; non-trivial test design |
+| **Lightweight** | one change file from the change template | small-but-real: ≲30 LOC net, ≤2 files, no new file, no public-API change, single straightforward test |
 | **Tiny** | none — conventional commit | typo, dep bump, linter/formatter/CI tweak, mechanical rename, single-line config |
 
-Heavier lane wins on ambiguity. A `change.md` that outgrows its lane splits
-into `design.md` + `plan.md`.
+Heavier lane wins on ambiguity. A lightweight change file that outgrows its lane is rewritten from the design template.
+
+### Plans are ephemeral
+
+The executable plan — task checklists, embedded code, commit sequences,
+whatever the executor needs — is a working artifact, not history. Keep it out
+of `changes/` and out of version control (git-ignored scratch, e.g.
+`.superpowers/`). Once the change ships, the diff and the PR are the record
+of execution; a committed plan duplicates them. `check-planning` rejects
+anything in `changes/` that is not a flat change file.
+
+### Lean specs
+
+The change file is the single home of a change's rationale:
+
+- The PR body summarizes and links to the change file — it never restates it.
+- Rejected alternatives live in `decisions/` and are referenced, not retold.
+- Show a sketch when the design needs code; never the full diff-to-be.
+- Delete template sections that don't apply — an empty section is ceremony.
+- Most designs fit well under ~700 words; length must buy information.
 
 ### Artifacts at a glance
 
-- **`design.md`** — the spec: the *thinking* (why, design, trade-offs, scope).
-- **`plan.md`** — the plan: the *sequencing* (the executor's task checklist).
-- **`change.md`** — both, condensed, for the lightweight lane.
+- **design template** — the spec: the *thinking* (why, design, trade-offs,
+  scope); the change file it produces is the single home of rationale (see
+  [Lean specs](#lean-specs)).
+- **change template** — the condensed spec for the lightweight lane.
 - **`releases/<semver>.md`** — per-release user-facing notes.
 - **`audits/<date>-<slug>.md`** — findings from a code/docs/bug-hunt sweep;
   spawns fix changes.
@@ -97,11 +134,10 @@ Templates live in [`_templates/`](_templates/).
 
 ### Frontmatter
 
-`date` and `slug` are **derived from the directory / file name** — never
+`date` and `slug` are **derived from the file name** — never
 repeated in frontmatter. So:
 
-- `design.md` / `change.md`: `summary` (single line) only.
-- `plan.md`: **no frontmatter** — its identity is the bundle directory.
+- `changes/*.md`: `summary` (single line) only.
 - `decisions/*.md`: `status` (accepted|superseded), `summary`, and optional
   `supersedes` / `superseded_by`.
 - Files in `architecture/` carry **no** frontmatter — living prose, dated by git.
@@ -113,8 +149,8 @@ only field the index renders.
 ## Index
 
 The listing is **generated**, not maintained — run `just index` to print it:
-changes as a flat newest-first list, then decisions newest-first. Each bundle's
-`summary` frontmatter (and the directory name, which supplies `date`/`slug`) is
+changes as a flat newest-first list, then decisions newest-first. Each change's
+`summary` frontmatter (and the file name, which supplies `date`/`slug`) is
 the single source of truth; there is no committed copy to drift.
 
 ## Other
 
@@ -5,8 +5,8 @@ summary: One line — shown in the generated index. Written at creation; finaliz
 # Change: One-line capitalized title
 
 **Lane:** lightweight — ≲30 LOC net, ≤2 files, no new file, no public-API
-change, a single straightforward test. If it outgrows this, split into
-`design.md` + `plan.md`.
+change, a single straightforward test. If it outgrows this, rewrite it from
+the design template.
 
 ## Goal
 
 
@@ -4,6 +4,10 @@ summary: One line — shown in the generated index. Written at creation; finaliz
 
 # Design: One-line capitalized title
 
+<!-- The single home of this change's rationale: the PR body summarizes and
+links here, never restates. Delete any section that doesn't apply — an empty
+section is ceremony. Most designs fit well under ~700 words. -->
+
 ## Summary
 
 One paragraph. What changes, at the level a reader needs to decide if this
@@ -12,37 +16,23 @@ spec is worth reading in full.
 ## Motivation
 
 Why now. What is broken or missing. Concrete observations / numbers, not
-abstract complaints. Link to memory entries or earlier specs when relevant.
-
-## Non-goals
-
-What is deliberately out of scope and (when nontrivial) why. Each item is
-a sentence; one line each.
+abstract complaints.
 
 ## Design
 
-### 1. <First piece>
-
 What changes, in enough detail that a reader who has not seen the codebase
-can follow. Code samples / diagrams welcome.
+can follow. Sketches and interface fragments welcome; never the full
+diff-to-be. Reference rejected alternatives in `decisions/` instead of
+retelling them.
 
-### 2. <Second piece>
-
-...
-
-## Operations
-
-Out-of-repo steps (DNS, infra, external account changes). Omit if none.
-
-## Out of scope
+## Non-goals
 
-Already covered above under Non-goals if appropriate. Repeat-list of
-explicitly-excluded follow-ups belongs here when the list is long.
+What is deliberately out of scope and (when nontrivial) why. One line each.
 
 ## Testing
 
-How we know it landed correctly. New pytest? Smoke check on live URL?
-Lint pass? Be specific.
+How we know it landed correctly. Be specific: the command and the expected
+signal.
 
 ## Risk
 
 
@@ -0,0 +1,15 @@
+# Glossary
+
+The project's ubiquitous language — the domain terms that code, specs, and
+capability pages share. Living prose, no frontmatter, dated by git. Each entry is
+a term, what it *is* (not what it does), and the synonyms to avoid. No
+implementation detail; this is a glossary, not a spec.
+
+**Term**:
+A one-or-two-sentence definition of what it is.
+_Avoid_: rejected-synonym, another-one
+
+**Another term**:
+Define what it is, tightly. Group related terms under `##` subheadings when
+natural clusters emerge; a flat list is fine when they don't.
+_Avoid_: …