Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@tools/uat-broker/main.go`:
- Around line 128-130: After FlagSet.Parse in both subcommand handlers, check
fs.Args() and return ExitInvalidInput when any unexpected positional arguments
remain. Update the reservations and schedule command handlers in main.go so they
reject extra trailing args instead of silently succeeding, using the existing
flagParseErr/invalid-input path and the handler functions that call
fs.Parse(args).
- Around line 137-140: The stdout writes in the `reservations` flow are ignoring
`Fprintln`/`Fprintf` errors, so failures like broken pipes or an unwritable
`$GITHUB_OUTPUT` can still return success. Update the `reservations` handling in
`main` to check and propagate every write error from `stdout` instead of
discarding it, and return a non-zero failure when any output write fails. Keep
the fix localized around the `list` branch and the later output-emission path so
the tool fails fast with the underlying write error.
- Around line 193-200: The warning in uat-broker’s schedule expansion path is
too broad: when ExpandSchedule produces empty cell lists because
--include-main=false and there are no stable tags, it should not be reported as
“main-only.” Update the warning logic around scheduleHasNoReleases in main to
distinguish an empty schedule from a degraded main-only schedule, and only emit
the main-only message when the schedule actually contains main rows; otherwise
use a precise empty/none-available warning.

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@tools/uat-broker/main.go`:
- Around line 282-284: The stdin size-limit guard in readTags is untested, so
add a unit test in main_test.go that exercises the oversized-input path by
calling readTags with a reader larger than maxTagsBytes and asserting it returns
an error; use the readTags function and the maxTagsBytes limit so the OOM
safeguard branch is covered.
- Around line 146-165: The reservations command in main/runReservations
currently lets `--list` override `--name`, so the conflicting flags are silently
accepted. Update the flag handling in the `switch` around `list`, `name == ""`,
and `reg.Lookup` to explicitly reject the `--list` + `--name` combination with
an invalid request error before listing or looking up reservations. Make sure
the validation sits alongside the existing argument checks in the same function
so workflow templating mistakes are surfaced instead of masked.

In `@tools/uat-broker/README.md`:
- Around line 62-65: The Exit codes section in the uat-broker README is missing
codes returned by the implementation. Update the documentation for the
runSchedule and runReservations behavior to include ErrCodeInternal for stdout
write/JSON encoding failures and ErrCodeTimeout for ctx-canceled stdin reads,
alongside the existing 0, 2, and 3 entries. Keep the table/wording aligned with
the actual pkg/errors coded contract so callers can branch correctly.

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In @.github/CODEOWNERS:
- Around line 44-47: The CODEOWNERS entry only covers tools/uat-broker/**, so
the new UAT directories are still inheriting `@nvidia/aicr-write`. Add explicit
owner rules for pkg/uatbroker/** and infra/uat/** in CODEOWNERS, or replace with
broader pkg/** and infra/** rules if those areas should require
`@nvidia/aicr-maintainer` approval; keep the existing tools/uat-broker/** rule
unchanged.

In `@pkg/uatbroker/registry.go`:
- Around line 105-112: Lookup currently returns a pointer to an element inside
Registry.Reservations, which lets callers mutate the registry’s internal state.
Update Registry.Lookup to return a copy of the matching Reservation instead of
&r.Reservations[i], while keeping the not-found error behavior unchanged. Use
the Lookup method and Reservation type as the main touchpoints when making the
change.

In `@pkg/uatbroker/schedule.go`:
- Around line 63-86: The sortedStableDescending helper in schedule.go should
guard against normalized-semver duplicates, since semver.NewVersion can coerce
different raw tags into the same semantic version and let both consume previousN
slots. Update the stable tag collection logic in sortedStableDescending to
de-dup by the normalized version identity (for example, the parsed semver
value’s canonical string) before sorting and returning the list, and keep the
existing filtering for blanks, invalid tags, and prereleases.

---

Outside diff comments:
In @.github/labeler.yml:
- Around line 15-23: The area/ci label rule is too narrow and misses other UAT
Broker-related changes. Update the labeler configuration in the area/ci rule so
it also matches pkg/uatbroker/** and infra/uat/** alongside tools/uat-broker/**,
ensuring UAT broker business logic and registry data changes get labeled
consistently. Use the existing area/ci entry in the labeler config as the place
to expand the affected globs.

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@tools/uat-broker/main.go`:
- Around line 117-167: In runReservations, validate the flag combination before
calling uatbroker.LoadRegistryFile so usage errors are returned first; move the
--list/--name mutual-exclusion check and the required-name check ahead of the
registry load, then only load the registry in the branch that actually needs it
for lookup or listing. Keep the existing error handling paths in runReservations
and flag parsing unchanged, but ensure the filesystem is not touched for invalid
flag combinations.