feat(#815): add /gsd-update --next to install the @next RC channel (#839)

Adds an opt-in --next (alias --rc) flag to /gsd-update targeting the @next RC dist-tag (ADR #660), with a {latest,next} allowlist enforced at three layers, channel-aware version check + banner, and byte-for-byte unchanged default @latest behavior.

Closes #815

.changeset/update-next-rc-channel.md

@@ -0,0 +1,5 @@
+---
+type: Added
+pr: 839
+---
+Added `/gsd-update --next` (alias `--rc`) to install or refresh from the `@next` RC dist-tag (ADR #660). A new `parse_update_channel` workflow step resolves the channel from `$ARGUMENTS`; the version check and all three npx install invocations thread `$TAG` instead of hardcoding `@latest`. When `--next` is used the version-comparison output gains a `Channel: next (RC)` banner so the user knows they are leaving the stable line; omitting the flag keeps `@latest` behavior byte-for-byte unchanged. `check-latest-version.cjs` gains `ALLOWED_TAGS`, `buildViewArgs`, and `resolveTag` exports, with an allowlist guard (enforced at both the CLI and function boundary) that rejects any dist-tag other than `latest`/`next`. (#815)

commands/gsd/update.md

@@ -1,7 +1,7 @@
 ---
 name: gsd:update
 description: Update GSD to latest version with changelog display
-argument-hint: "[--sync | --reapply]"
+argument-hint: "[--sync | --reapply | --next | --rc]"
 allowed-tools:
   - Read
   - Write
@@ -31,6 +31,7 @@ Routes to the update workflow which handles:
 <flags>
 - **--sync**: Sync managed GSD skills across runtime roots so multi-runtime users stay aligned after an update. Runs the sync-skills workflow (--from, --to, --dry-run, --apply flags supported).
 - **--reapply**: Reapply local modifications after a GSD update. Uses three-way comparison (pristine baseline, user-modified backup, newly installed version) to merge user customizations back. Runs the reapply-patches workflow.
+- **--next** (alias **--rc**): Target the `@next` RC dist-tag instead of `@latest` so you can install or refresh a release candidate (e.g. `1.4.0-rc.1`) through the normal update flow — scope/runtime detection, changelog preview, custom-file backup, and cache clearing all still apply. Omitting it keeps targeting `@latest` (no change). See ADR #660 for the RC channel.
 - **(no flag)**: Standard update — check for new version, show changelog, install.
 </flags>
 
@@ -38,7 +39,7 @@ Routes to the update workflow which handles:
 Parse the first token of $ARGUMENTS:
 - If it is `--sync`: strip the flag, execute the sync-skills workflow (passing remaining args for --from/--to/--dry-run/--apply).
 - If it is `--reapply`: strip the flag, execute the reapply-patches workflow.
-- Otherwise: execute the update workflow end-to-end.
+- Otherwise (including `--next` / `--rc`): execute the update workflow end-to-end, passing `$ARGUMENTS` through so the workflow's parse_update_channel step can select the release channel.
 
 </process>
 

docs/COMMANDS.md

@@ -1148,11 +1148,13 @@ Update GSD with changelog preview, and optionally sync skills or reapply local p
 |------|-------------|
 | `--sync` | Sync skills from the GSD registry after updating |
 | `--reapply` | Restore local modifications (patches) after updating |
+| `--next` / `--rc` | Target the `@next` RC dist-tag instead of `@latest` (installs or refreshes a release candidate, e.g. `1.4.0-rc.1`; see ADR #660) |
 
 ```bash
 /gsd-update                         # Check for updates and install
 /gsd-update --sync                  # Update and sync skills
 /gsd-update --reapply               # Update and reapply local patches
+/gsd-update --next                  # Install from the @next RC dist-tag
 ```
 
 ---

docs/FEATURES.md

@@ -904,6 +904,7 @@ continues. Drift detection cannot fail verification.
 - REQ-UPDATE-03: System MUST be runtime-aware and target the correct directory
 - REQ-UPDATE-04: System MUST back up locally modified files to `gsd-local-patches/`
 - REQ-UPDATE-05: `/gsd-update --reapply` MUST restore local modifications after update
+- REQ-UPDATE-06: `/gsd-update --next` (alias `--rc`) MUST target the `@next` RC dist-tag for version check and install; omitting the flag MUST keep `@latest` behavior unchanged (ADR #660)
 
 ---
 

docs/USER-GUIDE.md

@@ -830,6 +830,18 @@ Set `commit_docs: false` during `/gsd-new-project` or via `/gsd-settings`. Add `
 
 Since v1.17, the installer backs up locally modified files to `gsd-local-patches/`. Run `/gsd-update --reapply` to merge your changes back.
 
+### Install or Refresh a Release Candidate
+
+To install or refresh GSD from the `@next` RC dist-tag (the pre-release channel established by ADR #660), run:
+
+```bash
+/gsd-update --next
+# or equivalently:
+/gsd-update --rc
+```
+
+The same scope/runtime detection, changelog preview, custom-file backup, and cache clearing apply. Omitting `--next`/`--rc` keeps targeting `@latest` (stable channel, no change). Only the `@latest` and `@next` channels are supported — no arbitrary dist-tag can be passed.
+
 ### Cannot Update via npm
 
 See [docs/manual-update.md](manual-update.md) for a step-by-step manual update procedure.

docs/how-to/update-gsd.md

@@ -35,14 +35,34 @@ Restart your runtime after the update to pick up new commands and agents.
 |------|--------------|
 | `--sync` | After updating, sync skills from the GSD registry |
 | `--reapply` | After updating, merge locally modified GSD files back in from `gsd-local-patches/` |
+| `--next` / `--rc` | Target the `@next` RC dist-tag instead of `@latest` (installs or refreshes a release candidate; see ADR #660) |
 
 ```bash
 /gsd-update --sync        # Update and sync skills
 /gsd-update --reapply     # Update and reapply local patches
+/gsd-update --next        # Install from the @next RC dist-tag
 ```
 
 ---
 
+## Install or refresh a release candidate
+
+GSD publishes release candidates on the `@next` npm dist-tag (established by ADR #660). To install or refresh from that channel:
+
+```bash
+/gsd-update --next
+# or equivalently:
+/gsd-update --rc
+```
+
+The full update flow applies — scope/runtime detection, changelog preview, custom-file backup, and cache clearing all run normally. The only difference is that `check-latest-version.cjs` resolves the `@next` tag and npx installs from `@opengsd/gsd-core@next`.
+
+Only `latest` and `next` are supported channels; no arbitrary dist-tag can be passed (the script enforces an allowlist and exits with code 2 on an invalid tag).
+
+Omitting `--next`/`--rc` keeps targeting `@latest` (stable channel, no change in behavior).
+
+---
+
 ## Reviewing the changelog before updating
 
 `/gsd-update` always shows the changelog diff between your installed version and the latest *before* it asks for confirmation. You do not need to visit GitHub separately. The output looks like:

gsd-core/bin/check-latest-version.cjs

@@ -37,18 +37,64 @@ const CHECK_REASON = Object.freeze({
 
 const SEMVER_RE = /^\d+\.\d+\.\d+(?:[-+][0-9A-Za-z.-]+)?$/;
 
+// #815: the one RC channel ADR #660 sanctions, plus the stable default.
+// An allowlist (not a free string) keeps a typo from silently resolving
+// `npm view` to an empty or foreign dist-tag.
+const ALLOWED_TAGS = Object.freeze(['latest', 'next']);
+
+/**
+ * Build the `npm view` args for a dist-tag. `latest` keeps the bare package
+ * spec so the default invocation is byte-for-byte identical to before tag
+ * support existed (#815); any other allowlisted tag appends `@<tag>` so
+ * `npm view @opengsd/gsd-core@next version` resolves the RC channel (#660).
+ */
+function buildViewArgs(tag = 'latest') {
+  if (!ALLOWED_TAGS.includes(tag)) {
+    throw new RangeError(`invalid dist-tag '${tag}'; allowed: ${ALLOWED_TAGS.join(', ')}`);
+  }
+  const spec = tag === 'latest' ? PACKAGE_NAME : `${PACKAGE_NAME}@${tag}`;
+  return ['view', spec, 'version'];
+}
+
+/**
+ * Resolve the requested dist-tag from argv. Defaults to `latest` (no flag =>
+ * no behavior change). Restricted to ALLOWED_TAGS so a typo can't silently
+ * resolve to an empty/foreign tag (#815 alternative 1).
+ */
+function resolveTag(argv) {
+  let val;
+  const eq = argv.find((a) => typeof a === 'string' && a.startsWith('--tag='));
+  if (eq !== undefined) {
+    val = eq.slice('--tag='.length);
+  } else {
+    const i = argv.indexOf('--tag');
+    if (i === -1) return 'latest';
+    val = argv[i + 1];
+  }
+  if (!val || !ALLOWED_TAGS.includes(val)) {
+    throw new RangeError(
+      `invalid --tag '${val || ''}'; allowed: ${ALLOWED_TAGS.join(', ')}`,
+    );
+  }
+  return val;
+}
+
 /**
  * Pure-ish: takes an injected spawn function so tests don't actually run npm.
  * In production, defaults to execNpm() from the shell-projection seam.
  */
 function checkLatestVersion(opts = {}) {
+  const tag = opts.tag || 'latest';
+  if (!ALLOWED_TAGS.includes(tag)) {
+    throw new RangeError(`invalid dist-tag '${tag}'; allowed: ${ALLOWED_TAGS.join(', ')}`);
+  }
   // Default path routes through the shell-projection seam (execNpm owns the
   // Windows shell-flag policy and timeout default). The injection point
   // remains spawnSync-shaped for test compatibility — the adapter below
   // translates { exitCode } → { status } so the consumer logic is unchanged.
   // Bounded at 15s so a hung registry doesn't block /gsd-update (#2993 CR).
   const defaultSpawn = () => {
-    const r = execNpm(['view', PACKAGE_NAME, 'version'], { timeout: 15_000 });
+    const r = execNpm(buildViewArgs(tag), { timeout: 15_000 });
     return {
       status: r.exitCode,
       stdout: r.stdout,
@@ -90,8 +136,16 @@ function checkLatestVersion(opts = {}) {
 }
 
 function main() {
-  const json = process.argv.includes('--json');
+  const argv = process.argv.slice(2);
-  const r = checkLatestVersion();
+  const json = argv.includes('--json');
+  let tag;
+  try {
+    tag = resolveTag(argv);
+  } catch (e) {
+    process.stderr.write(`check-latest-version: ${e.message}\n`);
+    return 2;
+  }
+  const r = checkLatestVersion({ tag });
   if (json) {
     process.stdout.write(JSON.stringify(r) + '\n');
   } else if (r.ok) {
@@ -104,4 +158,4 @@ function main() {
 
 if (require.main === module) runMain(main);
 
-module.exports = { checkLatestVersion, CHECK_REASON, PACKAGE_NAME };
+module.exports = { checkLatestVersion, CHECK_REASON, PACKAGE_NAME, ALLOWED_TAGS, buildViewArgs, resolveTag };

gsd-core/workflows/help/modes/full.md

@@ -550,11 +550,12 @@ Usage: `/gsd:help --full`
 Usage: `/gsd:help debug`
 Usage: `/gsd:help --brief debug`
 
-**`/gsd:update [--sync] [--reapply]`**
+**`/gsd:update [--sync] [--reapply] [--next | --rc]`**
 Update GSD to latest version with changelog preview.
 
 - `--sync` — sync managed GSD skills across runtime roots (replaces the former `gsd-sync-skills`)
 - `--reapply` — reapply local modifications after an update (replaces the former `gsd-reapply-patches`)
+- `--next` (alias `--rc`) — install/refresh from the `@next` RC dist-tag instead of `@latest` (ADR #660); omit for the stable channel
 
 - Shows installed vs latest version comparison
 - Displays changelog entries for versions you've missed

gsd-core/workflows/update.md

@@ -75,6 +75,25 @@ If multiple runtime installs are detected and the invoking runtime cannot be det
 **If VERSION file missing (version resolves to `0.0.0`):** report the installed version as Unknown and proceed to install (treated as `0.0.0` for comparison).
 </step>
 
+<step name="parse_update_channel">
+Determine the release channel from `$ARGUMENTS`. This selects which npm dist-tag the entire update flow targets — `latest` (stable) by default, or `next` (the RC channel established by ADR #660) when the user opts in with `--next`/`--rc`:
+
+```bash
+case " $ARGUMENTS " in
+  *" --next "*|*" --rc "*)
+    TAG="next"
+    CHANNEL_LABEL="next (RC)"
+    ;;
+  *)
+    TAG="latest"
+    CHANNEL_LABEL="latest (stable)"
+    ;;
+esac
+```
+
+`TAG` is restricted to `latest`/`next` by `check-latest-version.cjs` (it rejects any other value with exit 2), so no arbitrary dist-tag can leak through. Omitting `--next`/`--rc` reproduces the prior behavior exactly: `TAG=latest`.
+</step>
+
 <step name="check_latest_version">
 Check npm for latest version via the deterministic script. **Do NOT run `npm view` or `npm search` directly** — the package name must come from the script, not from a free choice at execution time. (#2992: LLM-driven prescriptions of npm package names produced wrong-package queries; moving the package name into a script constant closes that gap.)
 
@@ -91,7 +110,7 @@ if [ -z "$GSD_DIR" ]; then
   LATEST_VERSION=""
   LATEST_REASON="no_install_detected"
 else
-  LATEST_RESULT="$(node "$GSD_DIR/gsd-core/bin/check-latest-version.cjs" --json 2>/dev/null)"
+  LATEST_RESULT="$(node "$GSD_DIR/gsd-core/bin/check-latest-version.cjs" --json --tag "$TAG" 2>/dev/null)"
   LATEST_STATUS=$?
   # #2993 CR: when node is missing or the script doesn't exist, LATEST_RESULT
   # is empty and piping it to `jq` produces a parse error on stderr while
@@ -114,7 +133,7 @@ fi
 ```text
 Couldn't check for updates (reason: {LATEST_REASON}, exit: {LATEST_STATUS}).
 
-To update manually: `npx -y --package=@opengsd/gsd-core@latest -- gsd-core --global`
+To update manually: `npx -y --package=@opengsd/gsd-core@{TAG} -- gsd-core --global`
 ```
 
 Exit.
@@ -123,6 +142,14 @@ Exit.
 <step name="compare_versions">
 Compare installed vs latest:
 
+**Only when `TAG=next`** (the user passed `--next`/`--rc`), prepend a channel banner so they know they are leaving the stable line — add this line immediately after the `**Latest:**` line in whichever output block renders:
+
+**Channel:** {CHANNEL_LABEL}
+
+On the default stable channel (`TAG=latest`), do NOT add a channel line — the output must match the prior stable behavior exactly.
+
+When `TAG=next`, the "latest" value is the release candidate published under `@next` (e.g. `1.4.0-rc.1`). Apply standard semver precedence for prereleases (`1.4.0-rc.1` is newer than `1.3.1` but older than the final `1.4.0`). Do NOT treat an `-rc.N` suffix as a dev install or as "behind" — offer it as an available update.
+
 **If installed == latest:**
 ```
 ## GSD Update
@@ -327,17 +354,17 @@ RUNTIME_FLAG="--$TARGET_RUNTIME"
 
 **If LOCAL install:**
 ```bash
-npx -y --package=@opengsd/gsd-core@latest -- gsd-core "$RUNTIME_FLAG" --local
+npx -y --package=@opengsd/gsd-core@"$TAG" -- gsd-core "$RUNTIME_FLAG" --local
 ```
 
 **If GLOBAL install:**
 ```bash
-npx -y --package=@opengsd/gsd-core@latest -- gsd-core "$RUNTIME_FLAG" --global
+npx -y --package=@opengsd/gsd-core@"$TAG" -- gsd-core "$RUNTIME_FLAG" --global
 ```
 
 **If UNKNOWN install:**
 ```bash
-npx -y --package=@opengsd/gsd-core@latest -- gsd-core --claude --global
+npx -y --package=@opengsd/gsd-core@"$TAG" -- gsd-core --claude --global
 ```
 
 Capture output. If install fails, show error and exit.

tests/bug-2992-check-latest-version.test.cjs

@@ -93,3 +93,62 @@ describe('Bug #2992: error paths', () => {
     assert.deepEqual(r, { ok: true, version: '1.40.0-rc.1', reason: CHECK_REASON.OK });
   });
 });
+
+describe('Issue #815: --next dist-tag support', () => {
+  const { buildViewArgs, resolveTag, ALLOWED_TAGS } = require(
+    path.join(ROOT, 'gsd-core', 'bin', 'check-latest-version.cjs'),
+  );
+
+  test('ALLOWED_TAGS is the sanctioned channel allowlist (latest, next)', () => {
+    assert.deepEqual([...ALLOWED_TAGS].sort(), ['latest', 'next']);
+  });
+
+  test('buildViewArgs() defaults to the bare latest spec (byte-for-byte unchanged)', () => {
+    assert.deepEqual(buildViewArgs(), ['view', '@opengsd/gsd-core', 'version']);
+    assert.deepEqual(buildViewArgs('latest'), ['view', '@opengsd/gsd-core', 'version']);
+  });
+
+  test('buildViewArgs("next") targets the @next dist-tag', () => {
+    assert.deepEqual(buildViewArgs('next'), ['view', '@opengsd/gsd-core@next', 'version']);
+  });
+
+  test('resolveTag defaults to latest when no --tag flag', () => {
+    assert.equal(resolveTag(['--json']), 'latest');
+  });
+
+  test('resolveTag reads --tag next', () => {
+    assert.equal(resolveTag(['--json', '--tag', 'next']), 'next');
+  });
+
+  test('resolveTag rejects an unknown tag (typo guard)', () => {
+    assert.throws(() => resolveTag(['--tag', 'nightly']), /invalid --tag 'nightly'/);
+  });
+
+  test('resolveTag rejects --tag with no value', () => {
+    assert.throws(() => resolveTag(['--tag']), /invalid --tag ''/);
+  });
+
+  test('checkLatestVersion accepts an RC under the next tag', () => {
+    const r = checkLatestVersion({ tag: 'next', spawn: () => ({ status: 0, stdout: '1.4.0-rc.1\n', stderr: '' }) });
+    assert.deepEqual(r, { ok: true, version: '1.4.0-rc.1', reason: CHECK_REASON.OK });
+  });
+
+  test('buildViewArgs rejects a tag outside the allowlist (exported-API guard)', () => {
+    assert.throws(() => buildViewArgs('nightly'), /invalid dist-tag 'nightly'/);
+  });
+
+  test('checkLatestVersion rejects an out-of-allowlist tag even with an injected spawn', () => {
+    assert.throws(
+      () => checkLatestVersion({ tag: 'nightly', spawn: () => ({ status: 0, stdout: '9.9.9\n', stderr: '' }) }),
+      /invalid dist-tag 'nightly'/,
+    );
+  });
+
+  test('resolveTag handles the --tag=next equals form', () => {
+    assert.equal(resolveTag(['--json', '--tag=next']), 'next');
+  });
+
+  test('resolveTag rejects an unknown --tag=value equals form (no silent fallback)', () => {
+    assert.throws(() => resolveTag(['--tag=nightly']), /invalid --tag 'nightly'/);
+  });
+});

tests/bug-3130-update-npx-robust-invocation.test.cjs

@@ -4,18 +4,20 @@
 // Regression guard for bug #3130.
 //
 // Two failure modes were observed with the pre-fix npx invocation form:
-//   1. Cache-stale: bare `npx -y @opengsd/gsd-core@latest` hits npx's local
+//   1. Cache-stale: bare `npx -y @opengsd/gsd-core@<tag>` hits npx's local
-//      cache and may pull an older version instead of @latest.
+//      cache and may pull an older version instead of the target tag.
 //   2. Token-routing: Bash-tool wrappers misroute the `@` token in
-//      `@opengsd/gsd-core@latest`, causing npm to error with
+//      `@opengsd/gsd-core@<tag>`, causing npm to error with
-//      "Unknown command: @opengsd/gsd-core@latest".
+//      "Unknown command: @opengsd/gsd-core@<tag>".
 //
 // The robust form is:
-//   npx -y --package=@opengsd/gsd-core@latest -- gsd-core $ARGS
+//   npx -y --package=@opengsd/gsd-core@"$TAG" -- gsd-core $ARGS
 //
 // `--package=` forces a fresh registry fetch, bypassing the npx cache.
 // `--` clearly delineates npx flags from the run-command, preventing
 // Bash-tool @-token misrouting.
+// `$TAG` is a shell variable (latest by default, next under --next/--rc),
+// set by the parse_update_channel step (#815).
 
 const { test } = require('node:test');
 const assert = require('node:assert/strict');
@@ -28,9 +30,9 @@ const UPDATE_WF = path.join(ROOT, 'gsd-core', 'workflows', 'update.md');
 const src = fs.readFileSync(UPDATE_WF, 'utf8');
 
 test('bug #3130: update.md contains no bare npx invocations (cache-stale form)', () => {
-  // Any occurrence of `npx -y @opengsd/gsd-core@latest` without `--package=`
+  // Any occurrence of `npx -y @opengsd/gsd-core@<something>` without `--package=`
   // is the stale form that triggers the two failure modes.
-  const stale = (src.match(/npx -y @opengsd\/gsd-core@latest[^\n]*/g) || []);
+  const stale = (src.match(/npx -y @opengsd\/gsd-core@\S+[^\n]*/g) || []);
   assert.deepEqual(
     stale,
     [],
@@ -40,7 +42,8 @@ test('bug #3130: update.md contains no bare npx invocations (cache-stale form)',
 
 test('bug #3130: update.md has >=3 robust npx invocations (--package= + -- separator)', () => {
   // Three sibling invocations: local, global, and unknown/fallback.
-  const robust = (src.match(/npx -y --package=@opengsd\/gsd-core@latest -- gsd-core/g) || []);
+  // The tag is now a $TAG variable (latest by default, next under --next/--rc).
+  const robust = (src.match(/npx -y --package=@opengsd\/gsd-core@\S+ -- gsd-core/g) || []);
   assert.ok(
     robust.length >= 3,
     `Expected >=3 robust npx invocations in update.md, found ${robust.length}`,

tests/issue-815-update-next-channel.test.cjs

@@ -0,0 +1,44 @@
+'use strict';
+// allow-test-rule: reads product workflow/command markdown to verify the --next RC channel contract — not a source-grep test
+
+// Issue #815: `/gsd-update --next` (alias `--rc`) must thread the @next dist-tag
+// through the whole update flow (version check + install) while leaving the
+// default @latest path unchanged.
+
+const { test } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const ROOT = path.join(__dirname, '..');
+const WF = fs.readFileSync(path.join(ROOT, 'gsd-core', 'workflows', 'update.md'), 'utf8');
+const CMD = fs.readFileSync(path.join(ROOT, 'commands', 'gsd', 'update.md'), 'utf8');
+
+test('issue #815: workflow parses --next/--rc into a TAG channel', () => {
+  assert.match(WF, /--next/);
+  assert.match(WF, /--rc/);
+  assert.match(WF, /TAG="next"/);
+  assert.match(WF, /TAG="latest"/);
+});
+
+test('issue #815: version check threads the tag through check-latest-version.cjs', () => {
+  // The script path is double-quoted in the shell command, so the line is:
+  //   node "$GSD_DIR/gsd-core/bin/check-latest-version.cjs" --json --tag "$TAG"
+  // The closing " on the script path sits between .cjs and --json.
+  assert.match(WF, /check-latest-version\.cjs"? --json --tag "\$TAG"/);
+});
+
+test('issue #815: install uses the selected tag, not a hardcoded @latest', () => {
+  const robust = WF.match(/npx -y --package=@opengsd\/gsd-core@"\$TAG" -- gsd-core/g) || [];
+  assert.ok(robust.length >= 3, `expected >=3 tag-parameterized npx invocations, found ${robust.length}`);
+  assert.doesNotMatch(WF, /--package=@opengsd\/gsd-core@latest -- gsd-core/,
+    'install lines must not hardcode @latest once --next exists');
+  assert.doesNotMatch(WF, /--package=@opengsd\/gsd-core@(?:latest|next|beta|canary|rc) -- gsd-core/,
+    'install lines must use the $TAG variable, never a hardcoded dist-tag literal');
+});
+
+test('issue #815: command documents --next/--rc and routes it to the update workflow', () => {
+  assert.match(CMD, /--next/);
+  assert.match(CMD, /--rc/);
+  assert.match(CMD, /argument-hint:.*--next/);
+});