Document the experimental Rush reporter demo

apps/rush/README.md

@@ -64,6 +64,10 @@ _(If you don't have a GitHub account set up, you can use `rush install --bypass-
 
 For more details and support resources, please visit: https://rushjs.io
 
+The repository also includes an
+[experimental Rush reporter opt-in and demo guide](../../docs/rush/reporter.md). Rush 5 retains legacy
+terminal output unless a reporter is explicitly enabled.
+
 ## Links
 
 - [CHANGELOG.md](

apps/rush/UPGRADING.md

@@ -1,5 +1,17 @@
 # Upgrade notes for @microsoft/rush
 
+### Experimental Rush reporter opt-in
+
+Rush 5 keeps the existing terminal output by default. Maintainers can evaluate the new reporter path for one
+invocation with `--reporter=<name>` or for a repository with `"useRushReporter": true` in
+`common/config/rush/experiments.json`.
+
+Use `RUSH_REPORTER=legacy` for an immediate reporter-only rollback. Environment-based automatic AI selection
+and the planned Rush 6 default change are not enabled yet.
+
+See the [experimental Rush reporter guide](../../docs/rush/reporter.md) for the control precedence, stdout and
+stderr contracts, full-log and privacy behavior, cross-version prerequisite, and reproducible demo.
+
 ### Rush 5.135.0
 
 This release of Rush deprecates the `rush-project.json`'s `operationSettings.sharding.shardOperationSettings`

apps/rush/src/test/sandbox/reporter-demo/README.md

@@ -1,27 +1,42 @@
 # Direct Rush reporter demo
 
-Build the three reporter projects, then run the self-checking direct invocation demo:
+For the complete control, compatibility, privacy, and troubleshooting reference, see the
+[experimental Rush reporter guide](../../../../../../docs/rush/reporter.md).
+
+From a clean checkout, install dependencies, build the reporter path, and run the self-checking direct
+invocation demo:
 
 ```sh
-rush build --to @microsoft/rush
+node common/scripts/install-run-rush.js install
+node common/scripts/install-run-rush.js build --to @microsoft/rush
 node apps/rush/src/test/sandbox/reporter-demo/run.mjs
 ```
 
 The script runs the same `rush build --only @rushstack/rush-reporter` operation stream through legacy,
 plaintext, JSON, AI, file, and quiet modes, plus parser failure, help, and command-specific JSON cases.
 It verifies payload-only machine stdout, one visible writer, ordered/lossless plaintext grouping from a
 same-invocation JSON sidecar, final artifact completeness, owner-only log permissions, failure flushing,
-AI parser-error context, command-JSON ownership, CI plaintext output, cache-path output, normalized
-`RUSH_TEMP_FOLDER` log placement, matching purge-path selection, and the `RUSH_REPORTER=legacy` rollback
-transcript. Captured stdout/stderr files are written to a temporary folder.
+AI parser-error context, command-JSON ownership, exclusive sidecar destinations, and the
+`RUSH_REPORTER=legacy` rollback transcript. Inherited `RUSH_REPORTER`, `RUSH_LOG_LEVEL`, and
+`RUSH_QUIET_MODE` values are removed from the self-check matrix. It also verifies CI plaintext output,
+cache-path output, a matching `RUSH_PREVIEW_VERSION`, normalized `RUSH_TEMP_FOLDER` log placement, and
+matching purge-path selection. Captured stdout/stderr files are written to a temporary folder.
+
+The final matrix case invokes `rush purge` with an isolated `RUSH_TEMP_FOLDER`. This also unlinks project
+dependencies, so run the install command again before continuing development in the checkout.
 
 For an individual invocation:
 
 ```sh
+# Interactive TTY only
+node apps/rush/bin/rush build --only @rushstack/rush-reporter --reporter=default
+
 node apps/rush/bin/rush build --only @rushstack/rush-reporter --reporter=plaintext
 node apps/rush/bin/rush build --only @rushstack/rush-reporter --reporter=json --log-level=debug
+RUSH_PREVIEW_VERSION=$(node -p "require('./apps/rush/package.json').version") node apps/rush/bin/rush build --only @rushstack/rush-reporter --reporter=json
 node apps/rush/bin/rush build --only @rushstack/rush-reporter --reporter=ai
 node apps/rush/bin/rush build --only @rushstack/rush-reporter --reporter=file
+RUSH_TEMP_FOLDER=./common/temp/reporter-demo-override node apps/rush/bin/rush build --only @rushstack/rush-reporter --reporter=file
 node apps/rush/bin/rush build --only @rushstack/rush-reporter --reporter=plaintext --log-level=quiet
 RUSH_REPORTER=legacy node apps/rush/bin/rush build --only @rushstack/rush-reporter --reporter=json
 node apps/rush/bin/rush list --json --reporter=file
@@ -30,3 +45,26 @@ node apps/rush/bin/rush list --json --reporter=file
 Repositories can opt in without a command-line flag by setting `"useRushReporter": true` in
 `common/config/rush/experiments.json`. Remove that setting or use `RUSH_REPORTER=legacy` for immediate
 rollback.
+
+The expected output is shape-based:
+
+- legacy keeps the existing Rush banner, operation blocks, and final status sections;
+- `default` uses a width-aware three-row live region and leaves a short final summary;
+- explicit `plaintext` groups ordered output under `project (phase)` and prints the absolute full-log path;
+- JSON stdout contains only NDJSON event envelopes;
+- a matching preview version keeps JSON stdout parseable and writes its warning to stderr;
+- AI stdout contains `ai.status` and bounded `ai.final` records;
+- file mode leaves stdout empty and writes the full-log path to stderr;
+- `RUSH_TEMP_FOLDER` moves the full log and the matching purge removes that override;
+- quiet mode retains only the final result and full-log path.
+
+The intentional missing-project AI failure preserves an actionable diagnostic and complete log reference.
+Structured remediation is included when the producing diagnostic supplies it; this parser failure does not
+currently provide a remediation action.
+
+After the demo exits, inspect the latest invocation log with:
+
+```sh
+ls -lt common/temp/rush-logs
+sed -n '1,120p' common/temp/rush-logs/latest.log
+```

apps/rush/src/test/sandbox/reporter-demo/run.mjs

@@ -7,13 +7,20 @@ import { fileURLToPath } from 'node:url';
 const scriptFolder = path.dirname(fileURLToPath(import.meta.url));
 const repoRoot = path.resolve(scriptFolder, '..', '..', '..', '..', '..', '..');
 const rushBin = path.join(repoRoot, 'apps', 'rush', 'bin', 'rush');
+const rushVersion = JSON.parse(
+  fs.readFileSync(path.join(repoRoot, 'apps', 'rush', 'package.json'), 'utf8')
+).version;
 const outputFolder = fs.mkdtempSync(path.join(os.tmpdir(), 'rush-reporter-demo-'));
 const commonArgs = ['build', '--only', '@rushstack/rush-reporter'];
+const baseEnv = { ...process.env };
+delete baseEnv.RUSH_REPORTER;
+delete baseEnv.RUSH_LOG_LEVEL;
+delete baseEnv.RUSH_QUIET_MODE;
 
 function run(name, args, env = {}, expectedStatus = 0) {
   const result = spawnSync(process.execPath, [rushBin, ...args], {
     cwd: repoRoot,
-    env: { ...process.env, ...env },
+    env: { ...baseEnv, ...env },
     encoding: 'utf8'
   });
   fs.writeFileSync(path.join(outputFolder, `${name}.stdout`), result.stdout);
@@ -40,6 +47,9 @@ const plaintext = run('plaintext', [
   `--output=json://${plaintextEventsPath}?logLevel=debug`
 ]).stdout;
 const json = run('json', [...commonArgs, '--reporter=json', '--log-level=debug']).stdout;
+const previewJson = run('preview-json', [...commonArgs, '--reporter=json'], {
+  RUSH_PREVIEW_VERSION: rushVersion
+});
 const ai = run('ai', [...commonArgs, '--reporter=ai']).stdout;
 const file = run('file', [...commonArgs, '--reporter=file']);
 const quiet = run('quiet', [...commonArgs, '--reporter=plaintext', '--log-level=quiet']).stdout;
@@ -62,6 +72,18 @@ const flagOffHelp = run('help-flag-off', ['--help']).stdout;
 const help = run('help', ['--help', '--reporter=json'], { RUSH_REPORTER: 'legacy' }).stdout;
 const commandJson = run('command-json', ['list', '--json', '--reporter=file']);
 const commandJsonConflict = run('command-json-conflict', ['list', '--json', '--reporter=json'], {}, 1);
+const duplicateOutputPath = path.join(outputFolder, 'duplicate-output.jsonl');
+const outputConflict = run(
+  'output-conflict',
+  [
+    ...commonArgs,
+    '--reporter=plaintext',
+    `--output=json://${duplicateOutputPath}`,
+    `--output=file://${duplicateOutputPath}`
+  ],
+  {},
+  1
+);
 const tempOverride = path.join(outputFolder, 'rush-temp-override');
 const tempOverrideFile = run('temp-override', [...commonArgs, '--reporter=file'], {
   RUSH_TEMP_FOLDER: tempOverride
@@ -94,6 +116,7 @@ function parseNdjson(text, name) {
 }
 
 const jsonEvents = parseNdjson(json, 'json');
+const previewJsonEvents = parseNdjson(previewJson.stdout, 'preview-json');
 const aiRecords = parseNdjson(ai, 'ai');
 const failureJsonEvents = parseNdjson(failureJson, 'failure-json');
 const failureAiRecords = parseNdjson(failureAi, 'failure-ai');
@@ -169,6 +192,12 @@ const aiFinal = aiRecords.at(-1);
 if (aiFinal?.kind !== 'ai.final' || aiFinal.log?.complete !== true) {
   throw new Error('AI output did not include a complete full-log reference.');
 }
+if (
+  !previewJson.stderr.includes('RUSH_PREVIEW_VERSION') ||
+  !previewJsonEvents.some((event) => event.type === 'sessionCompleted')
+) {
+  throw new Error('The matching preview version did not preserve payload-only reporter stdout.');
+}
 const failureAiFinal = failureAiRecords.at(-1);
 if (
   failureAiFinal?.result !== 'failed' ||
@@ -216,6 +245,9 @@ if (
 ) {
   throw new Error('Command-specific JSON ownership arbitration failed.');
 }
+if (outputConflict.stdout !== '' || !outputConflict.stderr.includes('is already owned by another reporter')) {
+  throw new Error('Duplicate reporter output destinations were not rejected.');
+}
 
 console.log(`Reporter demo outputs: ${outputFolder}`);
 console.log(`Full detail log: ${logMatch[1]}`);

common/changes/@microsoft/rush/copilot-reporter-r10a-demo-docs_2026-08-28-09-20.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "@microsoft/rush",
+      "comment": "Document the experimental reporter opt-in, rollback, output contracts, compatibility boundary, and reproducible demo.",
+      "type": "patch"
+    }
+  ],
+  "packageName": "@microsoft/rush",
+  "email": "TheLarkInn@users.noreply.github.com"
+}

common/changes/@rushstack/rush-reporter/copilot-reporter-r10a-demo-docs_2026-08-28-09-20.json

@@ -0,0 +1,11 @@
+{
+  "changes": [
+    {
+      "packageName": "@rushstack/rush-reporter",
+      "comment": "Add the opt-in reporter guide covering built-in renderers, full logs, privacy, and rollout safety.",
+      "type": "patch"
+    }
+  ],
+  "packageName": "@rushstack/rush-reporter",
+  "email": "TheLarkInn@users.noreply.github.com"
+}