diff --git a/.github/workflows/wai-conformance.yml b/.github/workflows/wai-conformance.yml
index 4668fa7b9..c64f286f1 100644
--- a/.github/workflows/wai-conformance.yml
+++ b/.github/workflows/wai-conformance.yml
@@ -895,6 +895,10 @@ jobs:
     if: needs.relevant.outputs.run == 'true'
     name: independent verifiers · claims, JWP, key discovery and integer payloads (Python)
     runs-on: linux-arm64
+    env:
+      WAI_FEATURES: key_discovery,http,video_manifest,stage_measure,live_events,live_room,capture_take,live_compose,live_record,timed_text,access_services,live_metering,energy_steering,live_moderation,dred_exact,live_ads,live_provenance,synthesis,synthesis_mark,neural_int,exact_upscale,robustness,ai_usage,contribution,settlement,browser_sink,receipt_claims,takedown,influence,direction,co_performance,age_assurance,bearer_receipts,exploration,co_watch,telemetry_aggregate,exact_tonemap,splat_exact,live_watermark,derive_edge
+      WAI_PQ_FEATURES: synthesis,pq_signatures
+      WAI_RELEASE_FEATURES: dred_exact,synthesis_mark,robustness
     steps:
       - uses: actions/checkout@v5
 
@@ -924,12 +928,64 @@ jobs:
         shell: bash
         run: python -m pip install cryptography
 
-      # differential.py drives wai_claim_vectors' `verdicts` mode; the key-discovery
-      # verdicts are compared with wai_signer_vectors'.
-      - name: Build the corpus verifiers wai-rs ships
+      # Every wai-rs step below runs with one of the three feature lists this job declares,
+      # so cargo builds each target once and every later `cargo test` finds it fresh. A step
+      # selects its tests exactly as before (`--lib <module>::` or `--test <name>`, with its
+      # filters); only the feature list is shared. Each feature still compiles alone in the
+      # `features-alone` job.
+      #
+      #   WAI_FEATURES          the union of every step's features but the hybrid signatures'.
+      #   WAI_PQ_FEATURES       the hybrid signatures step. `pq_signatures` changes what a build
+      #                         without it refuses (pq-signatures §6.3: such a build reads a
+      #                         hybrid member as an unknown one), so it stays out of the union
+      #                         and every other step keeps testing a build without it.
+      #   WAI_RELEASE_FEATURES  the steps that run their tests optimised (`--release`).
+      #
+      # Builds of the library that differ in features, or in the dependencies' features,
+      # write the same file, so each switch between two of them rebuilds it. `cargo build`
+      # and `cargo test` are two such builds (the dev-dependencies turn on wai-ops' `oracle`
+      # and serde_json's `preserve_order`), and so are two feature lists. Hence the order:
+      # the corpus tools the steps run as programs first, as `cargo build` builds them,
+      # copied to $RUNNER_TEMP/wai-bins/union and $RUNNER_TEMP/wai-bins/pq (the steps run
+      # those copies); then the union's test build, last, which every step but the hybrid
+      # signatures' runs; the release build has a directory of its own. The hybrid
+      # signatures step builds its tests itself, the one other build of the test profile.
+      #
+      # The last step's differentials drive wai_claim_vectors' and wai_jwp_vectors'
+      # `verdicts` modes, and compare wai_signer_vectors' key-discovery verdicts with
+      # signer_verify.py's. Both builds of the three are copied and both are held to the
+      # Python verifiers: the union's, which has key_discovery and no pq_signatures, and the
+      # hybrid signatures', which reads the hybrid members the other refuses.
+      - name: Build wai-rs once for every step below, and the corpus verifiers it ships
         working-directory: wai/wai-rs
         shell: bash
-        run: cargo build --no-default-features --features key_discovery --bin wai_claim_vectors --bin wai_jwp_vectors --bin wai_signer_vectors
+        run: |
+          set -euo pipefail
+          mkdir -p "$RUNNER_TEMP/wai-bins/union" "$RUNNER_TEMP/wai-bins/pq"
+          cargo build --no-default-features --features "$WAI_FEATURES" \
+            --bin wai_http_vectors --bin wai_stage_measure --bin wai_browser_sink_vectors \
+            --bin wai_claim_vectors --bin wai_jwp_vectors --bin wai_signer_vectors
+          for b in wai_http_vectors wai_stage_measure wai_browser_sink_vectors \
+              wai_claim_vectors wai_jwp_vectors wai_signer_vectors; do
+            cp "${CARGO_TARGET_DIR:-target}/debug/$b" "$RUNNER_TEMP/wai-bins/union/"
+          done
+          # Copied before this build replaces target/debug's copies of the three it shares.
+          cargo build --no-default-features --features "$WAI_PQ_FEATURES" \
+            --bin wai_pq_vectors --bin wai_claim_vectors --bin wai_jwp_vectors --bin wai_signer_vectors
+          for b in wai_pq_vectors wai_claim_vectors wai_jwp_vectors wai_signer_vectors; do
+            cp "${CARGO_TARGET_DIR:-target}/debug/$b" "$RUNNER_TEMP/wai-bins/pq/"
+          done
+          cargo test --no-run --no-default-features --features "$WAI_FEATURES" --lib \
+            --test live_events --test live_room --test capture_take --test live_compose --test live_record \
+            --test timed_text --test access_services --test live_metering --test energy_steering \
+            --test live_moderation --test live_ads --test ad_presentation --test live_provenance \
+            --test synthesis --test exact_upscale --test ai_usage --test contribution --test settlement \
+            --test browser_sink --test takedown --test influence --test direction --test co_performance \
+            --test age_assurance --test bearer_receipts --test exploration --test co_watch \
+            --test telemetry_aggregate --test exact_tonemap --test splat_exact --test live_watermark \
+            --test derive_edge
+          cargo test --release --no-run --no-default-features --features "$WAI_RELEASE_FEATURES" \
+            --test dred_exact --test dred_exact_measure --test synthesis_mark --test robustness
 
       # The integer payload corpus's second implementation (int-payload-conformance/README):
       # it parses every payload with the extension's rules and check order, converts every
@@ -979,9 +1035,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo build --no-default-features --features http,video_manifest,key_discovery --bin wai_http_vectors)
           for seed in 11 12; do
-            wai-rs/target/debug/wai_http_vectors fuzz http-conformance --seed "$seed" --count 400 --out "$RUNNER_TEMP/http-fuzz-$seed.json"
+            "$RUNNER_TEMP/wai-bins/union/wai_http_vectors" fuzz http-conformance --seed "$seed" --count 400 --out "$RUNNER_TEMP/http-fuzz-$seed.json"
             python3 http-conformance/http_verify.py cases "$RUNNER_TEMP/http-fuzz-$seed.json" http-conformance
           done
       # The staged-measurement corpus's second implementation (staged-measure-conformance/README):
@@ -1010,9 +1065,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo build --no-default-features --features stage_measure --bin wai_stage_measure)
           for seed in 1 2; do
-            python3 staged-measure-conformance/sim_diff.py wai-rs/target/debug/wai_stage_measure "$seed" 1500
+            python3 staged-measure-conformance/sim_diff.py "$RUNNER_TEMP/wai-bins/union/wai_stage_measure" "$seed" 1500
           done
       # wai.live.events (extensions/live-events.md): the reference module's unit tests and
       # tests/live_events.rs (the committed corpus regenerates byte for byte from its fixed
@@ -1027,8 +1081,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features live_events --lib live_events::)
-          (cd wai-rs && cargo test --no-default-features --features live_events --test live_events)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib live_events::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test live_events)
           python3 -I live-conformance/live_events_verify.py live-conformance/events
       # wai.live.room (extensions/live-rooms.md): the reference module's unit tests and
       # tests/live_room.rs (the committed corpus regenerates byte for byte from its fixed
@@ -1043,8 +1097,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features live_room --lib live_room::)
-          (cd wai-rs && cargo test --no-default-features --features live_room --test live_room)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib live_room::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test live_room)
           python3 -I live-conformance/live_rooms_verify.py live-conformance/rooms
       # wai.capture.take (extensions/capture-binding.md): the reference module's unit tests,
       # the output tree's (whose RFC 6962 hash and RFC 9162 consistency proofs the take tree
@@ -1061,8 +1115,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features capture_take --lib -- capture_take:: output_tree::)
-          (cd wai-rs && cargo test --no-default-features --features capture_take --test capture_take)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib -- capture_take:: output_tree::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test capture_take)
           python3 -I live-conformance/capture_take_verify.py live-conformance/takes
       # wai.live.compose (extensions/live-compose.md): the reference module's unit tests (the
       # layout over every grid of 1 to 64 tiles stays on its canvas with no tile overlapping
@@ -1081,8 +1135,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features live_compose --lib live_compose::)
-          (cd wai-rs && cargo test --no-default-features --features live_compose --test live_compose)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib live_compose::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test live_compose)
           python3 -I live-conformance/live_compose_verify.py live-conformance/compose
       # wai.live.recording (extensions/live-recording.md): the reference module's unit tests,
       # the output tree's (whose range proofs it adds, tested against RFC 9162 §2.1.3.2's
@@ -1100,8 +1154,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features live_record --lib -- live_record:: output_tree::)
-          (cd wai-rs && cargo test --no-default-features --features live_record --test live_record)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib -- live_record:: output_tree::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test live_record)
           python3 -I live-conformance/live_record_verify.py live-conformance/recordings
       # wai.text.timed (extensions/timed-text.md): the reference module's unit tests (cue model,
       # annotation, WebVTT, IMSC1 and its render-model bound, timelines, disclosure, and the
@@ -1119,8 +1173,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features timed_text --lib timed_text::)
-          (cd wai-rs && cargo test --no-default-features --features timed_text --test timed_text)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib timed_text::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test timed_text)
           python3 -I live-conformance/timed_text_verify.py live-conformance/captions
       # wai.access.services (extensions/access-services.md): the reference module's unit tests
       # (words, full and prefix alignment with their walk back, signed integers, gains) and
@@ -1138,8 +1192,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features access_services --lib access_services::)
-          (cd wai-rs && cargo test --no-default-features --features access_services --test access_services)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib access_services::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test access_services)
           python3 -I live-conformance/access_services_verify.py live-conformance/access
       # wai.live.metering (extensions/live-metering.md): the reference module's unit tests
       # (records and ledgers round-trip, the energy rules, the size bound at its limit, a
@@ -1159,8 +1213,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features live_metering --lib live_metering::)
-          (cd wai-rs && cargo test --no-default-features --features live_metering --test live_metering)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib live_metering::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test live_metering)
           python3 -I live-conformance/live_metering_verify.py live-conformance/metering
       # wai.live.steering (extensions/energy-steering.md): the reference module's unit tests
       # (policies and decisions round-trip and their rules refuse, the window, the request
@@ -1180,8 +1234,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features energy_steering --lib energy_steering::)
-          (cd wai-rs && cargo test --no-default-features --features energy_steering --test energy_steering)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib energy_steering::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test energy_steering)
           python3 -I live-conformance/energy_steering_verify.py live-conformance/steering
       # wai.live.moderation (extensions/live-moderation.md): the reference module's unit tests
       # (policies, statements and notices round-trip and their rules refuse, the export's
@@ -1201,8 +1255,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features live_moderation --lib live_moderation::)
-          (cd wai-rs && cargo test --no-default-features --features live_moderation --test live_moderation)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib live_moderation::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test live_moderation)
           python3 -I live-conformance/live_moderation_verify.py live-conformance/moderation
       # wai.audio.opus.dred.int (extensions/opus-dred.md): first the draft's weights file and
       # test vectors, which the corpus names by SHA-256 and does not hold, fetched from the
@@ -1227,9 +1281,9 @@ jobs:
           d="${RUNNER_TEMP:-/tmp}/dred"
           bash live-conformance/dred/fetch.sh "$d" vectors
           w="$d/dred_unquantized_weights.bin"
-          (cd wai-rs && cargo test --no-default-features --features dred_exact --lib dred_exact::)
-          (cd wai-rs && WAI_DRED_WEIGHTS="$w" cargo test --release --no-default-features --features dred_exact --test dred_exact)
-          (cd wai-rs && WAI_DRED_WEIGHTS="$w" WAI_DRED_VECTORS="$d" cargo test --release --no-default-features --features dred_exact --test dred_exact_measure)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib dred_exact::)
+          (cd wai-rs && WAI_DRED_WEIGHTS="$w" cargo test --release --no-default-features --features "$WAI_RELEASE_FEATURES" --test dred_exact)
+          (cd wai-rs && WAI_DRED_WEIGHTS="$w" WAI_DRED_VECTORS="$d" cargo test --release --no-default-features --features "$WAI_RELEASE_FEATURES" --test dred_exact_measure)
           python3 -I live-conformance/dred_verify.py live-conformance/dred "$w"
       # wai.live.ads (extensions/live-ads.md): the reference module's unit tests (policies and
       # annotations round-trip and their rules refuse, a break's identity, tags, events and
@@ -1250,9 +1304,9 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features live_ads --lib live_ads::)
-          (cd wai-rs && cargo test --no-default-features --features live_ads --lib wai_video_ssai::)
-          (cd wai-rs && cargo test --no-default-features --features live_ads --test live_ads)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib live_ads::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib wai_video_ssai::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test live_ads)
           python3 -I live-conformance/live_ads_verify.py live-conformance/ads
       # wai.live.ad_presentation (extensions/ad-presentation.md): the reference module's unit
       # tests (claims round-trip and their rules refuse, the quartile, the qualifying run, the
@@ -1272,8 +1326,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features live_ads --lib live_ads::presentation::)
-          (cd wai-rs && cargo test --no-default-features --features live_ads --test ad_presentation)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib live_ads::presentation::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test ad_presentation)
           python3 -I live-conformance/ad_presentation_verify.py live-conformance/presentation
           node --test ../joule-code/joule-code-rs/crates/joule-moq-web/web/ads/presentation.test.mjs
       # wai.live.provenance (extensions/live-provenance.md): the reference module's unit tests
@@ -1294,8 +1348,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features live_provenance --lib live_provenance::)
-          (cd wai-rs && cargo test --no-default-features --features live_provenance --test live_provenance)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib live_provenance::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test live_provenance)
           python3 -I live-conformance/c2pa_live_verify.py live-conformance/c2pa-live
       # wai.media.synthesis (extensions/synthesis.md): the reference module's unit tests (the
       # pinned derivations by their rules, the class lattice, a generator's envelope) and
@@ -1314,8 +1368,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features synthesis --lib synthesis::)
-          (cd wai-rs && cargo test --no-default-features --features synthesis --test synthesis)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib synthesis::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test synthesis)
           python3 -I live-conformance/synthesis_verify.py live-conformance/synthesis
       # The registered watermark schemes wai-mark:tent64 and wai-mark:tent64s
       # (extensions/synthesis.md §7.4 to §7.9): the reference's unit tests (the code corrects 29
@@ -1339,8 +1393,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features synthesis_mark --lib -- synthesis::mark synthesis_mark::)
-          (cd wai-rs && cargo test --release --no-default-features --features synthesis_mark --test synthesis_mark)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib -- synthesis::mark synthesis_mark::)
+          (cd wai-rs && cargo test --release --no-default-features --features "$WAI_RELEASE_FEATURES" --test synthesis_mark)
           python3 -I live-conformance/synthesis_mark_verify.py live-conformance/synthesis-mark
       # wai.media.upscale (extensions/exact-upscale.md): the integer super-resolution
       # derivations' unit tests (the wai-ops/1 graph against the arithmetic of §3.2 written out
@@ -1361,9 +1415,9 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features neural_int --lib int_sr::)
-          (cd wai-rs && cargo test --no-default-features --features exact_upscale --lib exact_upscale::)
-          (cd wai-rs && cargo test --no-default-features --features exact_upscale --test exact_upscale)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib int_sr::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib exact_upscale::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test exact_upscale)
           python3 -I live-conformance/upscale_verify.py live-conformance/upscale
       # Robustness evidence for soft bindings (extensions/robustness-evidence.md): the
       # reference's unit tests (gamma is the rounded power, rates are exact and reduced, every
@@ -1385,8 +1439,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features robustness --lib robustness::)
-          (cd wai-rs && cargo test --release --no-default-features --features robustness --test robustness)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib robustness::)
+          (cd wai-rs && cargo test --release --no-default-features --features "$WAI_RELEASE_FEATURES" --test robustness)
           python3 -I live-conformance/robustness_verify.py live-conformance/robustness
       # wai.ai.usage (extensions/ai-usage.md): the reference module's unit tests (RFC 9651's
       # Dictionary parser against the vocabulary's examples and the RFC's edges, statements
@@ -1409,9 +1463,9 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features ai_usage --lib ai_usage::)
-          (cd wai-rs && cargo test --no-default-features --features ai_usage --lib claim_receipt::consumption::)
-          (cd wai-rs && cargo test --no-default-features --features ai_usage --test ai_usage)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib ai_usage::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib claim_receipt::consumption::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test ai_usage)
           python3 -I live-conformance/ai_usage_verify.py live-conformance/usage
           python3 -I claim-conformance/claim_verify.py consumption live-conformance/usage/vectors.json
       # wai.media.contribution (extensions/contribution.md): the reference module's unit tests
@@ -1433,8 +1487,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features contribution --lib contribution::)
-          (cd wai-rs && cargo test --no-default-features --features contribution --test contribution)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib contribution::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test contribution)
           python3 -I live-conformance/contribution_verify.py live-conformance/contribution
       # wai.delivery.settlement (extensions/settlement.md): the reference module's unit tests
       # (range proofs over every range around every chunk boundary of objects of many lengths
@@ -1456,8 +1510,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features settlement --lib settlement::)
-          (cd wai-rs && cargo test --no-default-features --features settlement --test settlement)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib settlement::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test settlement)
           python3 -I live-conformance/settlement_verify.py live-conformance/settlement
       # The browser sink (extensions/browser-sink.md): the reference module's unit tests (the
       # registry gate's rows, registered tiers, integers as §5 reads them, a binding's
@@ -1481,10 +1535,9 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features browser_sink --lib browser_sink::)
-          (cd wai-rs && cargo test --no-default-features --features browser_sink,receipt_claims --test browser_sink)
-          (cd wai-rs && cargo run -q --no-default-features --features browser_sink --bin wai_browser_sink_vectors -- verify ../live-conformance/browser)
-          (cd wai-live-web && cargo test --locked --lib browser_tests)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib browser_sink::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test browser_sink)
+          (cd wai-rs && "$RUNNER_TEMP/wai-bins/union/wai_browser_sink_vectors" verify ../live-conformance/browser)
           (cd wai-live-web && cargo test --locked --features int_video --lib browser_tests)
           python3 -I live-conformance/browser_sink_verify.py live-conformance/browser
       # wai.media.takedown (extensions/takedown.md): the reference module's unit tests (times,
@@ -1507,8 +1560,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features takedown --lib takedown::)
-          (cd wai-rs && cargo test --no-default-features --features takedown --test takedown)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib takedown::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test takedown)
           python3 -I live-conformance/takedown_verify.py live-conformance/takedown
       # wai.media.influence (extensions/influence.md): the reference module's unit tests (the
       # blend keeps its base and its references by weight, the makers' split is whole, an
@@ -1529,8 +1582,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features influence --lib influence::)
-          (cd wai-rs && cargo test --no-default-features --features influence --test influence)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib influence::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test influence)
           python3 -I live-conformance/influence_verify.py live-conformance/influence
       # wai.media.direction (extensions/direction.md): the reference module's unit tests (the
       # interpolations reach both keys and stay between them, the framing measure at its bounds,
@@ -1552,8 +1605,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features direction --lib direction::)
-          (cd wai-rs && cargo test --no-default-features --features direction --test direction)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib direction::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test direction)
           python3 -I live-conformance/direction_verify.py live-conformance/direction
       # wai.live.coperformance (extensions/co-performance.md): the reference module's unit tests
       # (the policy and every statement round-trip and their rules refuse, the attributes'
@@ -1573,8 +1626,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features co_performance --lib co_performance::)
-          (cd wai-rs && cargo test --no-default-features --features co_performance --test co_performance)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib co_performance::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test co_performance)
           python3 -I live-conformance/co_performance_verify.py live-conformance/coperformance
       # wai.age.assurance (extensions/age-assurance.md): the reference module's unit tests (the
       # pinned AlgorithmIdentifier and RFC 9578's first vector through this module, the
@@ -1594,8 +1647,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features age_assurance --lib age_assurance::)
-          (cd wai-rs && cargo test --no-default-features --features age_assurance --test age_assurance)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib age_assurance::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test age_assurance)
           python3 -I live-conformance/age_assurance_verify.py live-conformance/age
       # wai.bearer.receipts (extensions/bearer-receipts.md): the reference module's unit tests
       # (the bound, the bitmap rules, the bearer classes, and the corpus reaching every stated
@@ -1619,8 +1672,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features bearer_receipts --lib bearer)
-          (cd wai-rs && cargo test --no-default-features --features bearer_receipts --test bearer_receipts)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib bearer)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test bearer_receipts)
           python3 -I live-conformance/bearer_verify.py live-conformance/bearers
           python3 -I claim-conformance/claim_verify.py bearer live-conformance/bearers/vectors.json
       # wai.media.exploration (extensions/exploration.md): the reference module's unit tests (the
@@ -1643,8 +1696,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features exploration --lib exploration::)
-          (cd wai-rs && cargo test --no-default-features --features exploration --test exploration)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib exploration::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test exploration)
           python3 -I live-conformance/exploration_verify.py live-conformance/exploration
       # wai.live.cowatch (extensions/co-watch.md): the reference module's unit tests (the policy
       # and its rules, statements read back and refused, the controlled position in the order of
@@ -1666,8 +1719,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features co_watch --lib co_watch::)
-          (cd wai-rs && cargo test --no-default-features --features co_watch --test co_watch)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib co_watch::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test co_watch)
           python3 -I live-conformance/co_watch_verify.py live-conformance/cowatch
           node --test ../joule-code/joule-code-rs/crates/joule-moq-web/web/room/cowatch.test.mjs
       # wai.telemetry.aggregate (extensions/telemetry-aggregation.md): the reference module's unit
@@ -1693,8 +1746,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features telemetry_aggregate --lib -- telemetry_aggregate:: telemetry::)
-          (cd wai-rs && cargo test --no-default-features --features telemetry_aggregate --test telemetry_aggregate)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib -- telemetry_aggregate:: telemetry::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test telemetry_aggregate)
           python3 -I live-conformance/telemetry_aggregate_verify.py live-conformance/aggregate
       # wai.media.tonemap, wai.meta.gainmap and wai.meta.st2094_50 (extensions/exact-tonemap.md):
       # the reference module's unit tests (the fixed-point log2 and exp2 at known points, the
@@ -1716,8 +1769,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features exact_tonemap --lib -- exact_tonemap:: png_still::)
-          (cd wai-rs && cargo test --no-default-features --features exact_tonemap --test exact_tonemap)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib -- exact_tonemap:: png_still::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test exact_tonemap)
           python3 -I live-conformance/tonemap_verify.py live-conformance/tonemap
       # wai.splat.exact (extensions/splat-exact.md): the reference module's unit tests
       # (exp_neg_q16 against the exponential, binary32 ranges rounded half up exactly, the
@@ -1739,8 +1792,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features splat_exact --lib splat_exact::)
-          (cd wai-rs && cargo test --no-default-features --features splat_exact --test splat_exact)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib splat_exact::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test splat_exact)
           python3 -I live-conformance/splat_exact_verify.py live-conformance/splat
       # wai.live.e2ee (extensions/confidentiality.md): the corpus's second implementation,
       # e2ee_verify.py, written from the extension's text and the documents it reads and
@@ -1773,8 +1826,8 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features live_watermark --lib live_watermark::)
-          (cd wai-rs && cargo test --no-default-features --features live_watermark --test live_watermark)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib live_watermark::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test live_watermark)
           python3 -I live-conformance/live_watermark_verify.py live-conformance/watermark
       # wai.edge.derivation (extensions/deriving-edge.md): the reference module's unit tests
       # (the operations pixel by pixel, which operations the registry's composition rule makes
@@ -1796,9 +1849,9 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features derive_edge --lib derive_edge::)
-          (cd wai-rs && cargo test --no-default-features --features derive_edge --lib png_still::)
-          (cd wai-rs && cargo test --no-default-features --features derive_edge --test derive_edge)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib derive_edge::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --lib png_still::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_FEATURES" --test derive_edge)
           python3 -I edge-conformance/edge_verify.py edge-conformance
       # The quantum corpus's second implementation (quantum-sim extension), integers only:
       # it derives the circuit/1 phase table by its recurrence and the circuit2 table by an
@@ -1836,12 +1889,12 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          (cd wai-rs && cargo test --no-default-features --features pq_signatures --lib pq_sig::)
-          (cd wai-rs && cargo test --no-default-features --features synthesis,pq_signatures --lib synthesis::pq_tests)
-          (cd wai-rs && cargo test --no-default-features --features pq_signatures --test pq_signatures)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_PQ_FEATURES" --lib pq_sig::)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_PQ_FEATURES" --lib synthesis::pq_tests)
+          (cd wai-rs && cargo test --no-default-features --features "$WAI_PQ_FEATURES" --test pq_signatures)
           python3 -I pq-conformance/pq_verify.py pq-conformance
           python3 -I pq-conformance/pq_verify.py verdicts pq-conformance/vectors.json > "$RUNNER_TEMP/pq-py.tsv"
-          (cd wai-rs && cargo run -q --no-default-features --features pq_signatures --bin wai_pq_vectors -- verdicts ../pq-conformance/vectors.json) > "$RUNNER_TEMP/pq-rs.tsv"
+          (cd wai-rs && "$RUNNER_TEMP/wai-bins/pq/wai_pq_vectors" verdicts ../pq-conformance/vectors.json) > "$RUNNER_TEMP/pq-rs.tsv"
           diff "$RUNNER_TEMP/pq-py.tsv" "$RUNNER_TEMP/pq-rs.tsv"
       - name: claim_verify.py, differential.py, jwp_verify.py, chain_differential.py, chain_gap_differential.py, signer_verify.py
         working-directory: wai
@@ -1849,16 +1902,72 @@ jobs:
         run: |
           set -euo pipefail
           python3 claim-conformance/claim_verify.py claim-conformance/vectors.json
-          python3 claim-conformance/differential.py "$GITHUB_WORKSPACE/wai/wai-rs/target/debug/wai_claim_vectors" --random 2000 --seed 1
           python3 jwp-conformance/jwp_verify.py jwp-conformance/vectors.json
-          for seed in 1 2; do
-            python3 jwp-conformance/chain_differential.py "$GITHUB_WORKSPACE/wai/wai-rs/target/debug/wai_jwp_vectors" --n 3000 --seed "$seed"
-            python3 jwp-conformance/chain_gap_differential.py "$GITHUB_WORKSPACE/wai/wai-rs/target/debug/wai_jwp_vectors" --n 400 --seed "$seed"
-          done
           python3 signer-conformance/signer_verify.py signer-conformance/vectors.json
           python3 signer-conformance/signer_verify.py verdicts signer-conformance/vectors.json > "$RUNNER_TEMP/signer-py.tsv"
-          "$GITHUB_WORKSPACE/wai/wai-rs/target/debug/wai_signer_vectors" verdicts signer-conformance/vectors.json > "$RUNNER_TEMP/signer-rs.tsv"
-          diff "$RUNNER_TEMP/signer-py.tsv" "$RUNNER_TEMP/signer-rs.tsv"
+          # Each differential against both builds the first step copied (see its comment).
+          for build in union pq; do
+            bins="$RUNNER_TEMP/wai-bins/$build"
+            if [ "$build" = pq ]; then features=$WAI_PQ_FEATURES; else features=$WAI_FEATURES; fi
+            echo "::group::the differentials against the $build build (features $features)"
+            python3 claim-conformance/differential.py "$bins/wai_claim_vectors" --random 2000 --seed 1
+            for seed in 1 2; do
+              python3 jwp-conformance/chain_differential.py "$bins/wai_jwp_vectors" --n 3000 --seed "$seed"
+              python3 jwp-conformance/chain_gap_differential.py "$bins/wai_jwp_vectors" --n 400 --seed "$seed"
+            done
+            "$bins/wai_signer_vectors" verdicts signer-conformance/vectors.json > "$RUNNER_TEMP/signer-rs-$build.tsv"
+            diff "$RUNNER_TEMP/signer-py.tsv" "$RUNNER_TEMP/signer-rs-$build.tsv"
+            echo "the $build build: every differential agrees"
+            echo "::endgroup::"
+          done
+
+  # Each feature list a step of the independent verifiers built alone, before those steps
+  # shared one build of the union, still compiles alone: a feature that compiles only beside
+  # another passes there and would fail a consumer that asks for it alone. A check, with no
+  # code generation, of every target the list enables (`--tests`: the library, as itself and
+  # as its unit tests see it, its binaries and its integration tests), for each list in turn;
+  # the tests themselves run in that job, under the union.
+  features-alone:
+    needs: relevant
+    if: needs.relevant.outputs.run == 'true'
+    name: each feature of the independent verifiers' steps compiles alone
+    # A check, so any architecture serves; linux-arm64 has the free slots.
+    runs-on: linux-arm64
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Install Rust 1.98.0
+        shell: bash
+        run: |
+          export PATH="$HOME/.cargo/bin:$PATH"
+          command -v rustup >/dev/null 2>&1 || \
+            curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --profile minimal --default-toolchain 1.98.0
+          rustup toolchain install 1.98.0 --profile minimal
+          rustup default 1.98.0
+          echo "$HOME/.cargo/bin" >> "$GITHUB_PATH"
+
+      - name: wai-rs, each feature list alone
+        working-directory: wai/wai-rs
+        shell: bash
+        run: |
+          set -euo pipefail
+          for f in key_discovery http,video_manifest,key_discovery stage_measure live_events live_room \
+              capture_take live_compose live_record timed_text access_services live_metering energy_steering \
+              live_moderation dred_exact live_ads live_provenance synthesis synthesis_mark neural_int \
+              exact_upscale robustness ai_usage contribution settlement browser_sink browser_sink,receipt_claims \
+              takedown influence direction co_performance age_assurance bearer_receipts exploration co_watch \
+              telemetry_aggregate exact_tonemap splat_exact live_watermark derive_edge pq_signatures \
+              synthesis,pq_signatures; do
+            echo "::group::$f"
+            cargo check --no-default-features --features "$f" --tests
+            echo "::endgroup::"
+          done
+
+      # The browser sink step runs wai-live-web's tests with `int_video` only: they are a
+      # superset of the default build's, and the feature gates nothing off.
+      - name: wai-live-web without int_video
+        working-directory: wai/wai-live-web
+        run: cargo check --locked --tests
 
   # Delivery telemetry's second implementation is an independent open-source CMCD and CMSD
   # library at locked versions (telemetry-conformance/cml/package-lock.json). The