[rush] Rush Reporter Overhaul

Some Issues w/ Rush Terminal Reporting today:

• We have no reporter system in place.
• AI models struggle to work with rush for a variety of reasons
  • Long running processes occupying the foreground
  • Terminal output is super verbose by default - eats up lots of the default context window
  • Error messages don't provide the best context or assistance (for both users and agents)

Plan:

• Most linting and coverage tools have a --reporter feature which customizes output based on where and how it is being run (ci, local machine, even OS specific). Leverage COPILOT_CLI env variable to auto trigger an AI reporter system --reporter=ai that will provide agent-optimized terminal feedback. Based on eval's we can tweak the format to be JSON, Plaintext, Markdown, etc. and determine the level of verbosity (or not) that works best for agents.
• Once we have a --reporter system, drastically reduce the default reporter output for all rush <command name> commands to minimal. P0 would be to get rid of the long diagnostic feedback of rush build and replace with 3 things consuming no more than a few lines:
  • Spinner/progress bar to indicate progress
  • One line dynamic activity marquee that reassures users that the command is still running. (What project currently getting built, etc)
  • One line result with standard exit code and output
• Errors get migrated to have a new hierarchy that both the AI and default reporters can respond/visualize in specific ways

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📦 Implementation status (updated 2026-07-15)

The RFC (specs/2026-07-12-rush-reporter-overhaul.md) and the standalone @rushstack/rush-reporter public-beta package (28/28 features) have landed as a 6-PR stack:

PR	Phase
#5865	1 · Contracts & baselines (package scaffold, event envelope, producer API, diagnostics, NDJSON protocol, ReporterManager, goldens)
#5866	2 · Bootstrap & compatibility adapters
#5867	3 · Shadow structured emission (session, lifecycle, telemetry, exit codes)
#5868	4 · Opt-in reporters (default/plaintext/json/ai/file/legacy, selection, StreamCollator replacement, problem matchers)
#5869	5 · Heft protocol track
#5870	6 · Performance budgets & daemon-aligned major default flip

⚠️ Not yet enabled in the live CLI. The package is standalone — nothing in rush-lib/apps/rush imports it yet, so rush build still renders through the legacy StreamCollator. The P0 3-line default (spinner + activity marquee + result) described above ships when the rollout steps below are complete.

✅ Remaining work to enable the new reporting system

Wire the package into the toolchain

• Add @rushstack/rush-reporter as a dependency of rush-lib and apps/rush (RFC §5.1)
• Generate the frozen bootstrap-envelope encoder + protocol-major constant into the zero-dependency install-run-rush build (RFC §5.1)

Bootstrap prelude — install-run-rush (Phase 2)

• Add the two-stage prelude: parse early controls and buffer Rush-owned startup events to the handoff file before rush-lib loads (RFC §5.5)
• Publish the handoff-file path via env var for the frontend to replay

Frontend host — apps/rush (Phase 2)

• Create the authoritative ReporterManager before version selection; replay then delete the bootstrap handoff (RFC §4.3)
• Install cross-version compatibility adapters (new-frontend/old-engine, old-frontend/new-engine) keeping legacy rendering visible

Engine integration — rush-lib (Phases 3–4)

• Expose the RushSession event sink + scoped producers to actions and plugins (RFC §5.3)
• Emit shadow structured lifecycle + diagnostic events with no output change; validate telemetry + exit-code parity (Phase 3)
• Replace StreamCollator in OperationExecutionManager with raw semantic operation events, gated on the new reporter path (RFC §5.13)
• Register CLI controls in ts-command-line: --reporter, --output, --log-level, and the --quiet/--verbose/--debug aliases (RFC §5.6–5.7)
• Read agentEnvironmentVariables + reporter config from rush.json (RFC §5.8)
• Wire the telemetry projection subscriber into Rush's telemetry path (RFC §5.17)
• Derive command exit codes via deriveExitCodeFromEvents (RFC §5.18)

Heft integration (Phase 5)

• Teach Heft to negotiate the child descriptor and emit NDJSON; retain raw-stream fallback for older Heft (RFC §5.19)
• Register problem matchers for external/child output recovery (RFC §5.16)

Compatibility & deprecations (Phase 6 — daemon-aligned major)

• Deprecate, then remove, ILogger.terminal and RushSession.terminalProvider (RFC §5.3)
• Gate incompatible plugins before apply() with the structured migration diagnostic (RFC §5.3)
• Bridge legacy AlreadyReportedError sentinels and prohibit new usage (RFC §5.15)
• Preserve the RUSH_REPORTER=legacy emergency fallback for ≥1 major (RFC §8.2)

Rollout controls & gates (RFC §8.2)

• Add the experimental repository setting (experiments.json) for pre-major opt-in
• Pass the deterministic AI-corpus gates before enabling agent auto-selection
• Flip defaults in the daemon-aligned major: automatic selection on, terminal APIs removed (Phase 6)

Docs & later cleanup (Phase 7)

• Document migration, verbosity aliases, RUSH_REPORTER, and --reporter/--output
• (Later major) Remove the legacy renderer after ≥1 major of default use with no blocking canary regressions
• (Later major) Remove the AlreadyReportedError bridge once ecosystem criteria are met