diff --git a/.circleci/config.yml b/.circleci/config.yml
index 2e5d2c1460..f97654c2d0 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -420,11 +420,11 @@ jobs:
               client/java/opensysml-client/src/main/java/org/openmbee/opensysml/proto
 
   # The race-enabled suite. It is the longest single step in the pipeline, so
-  # it gets the larger class and four executors, one named package shard each.
+  # it gets the larger class and five executors, one named package shard each.
   go-race-test:
     executor: go-executor
     resource_class: large
-    parallelism: 4
+    parallelism: 5
     steps:
       - checkout
       - go/load-cache
@@ -444,7 +444,7 @@ jobs:
           name: Run Go race tests
           command: |
             set -o pipefail
-            shards=(runtime model export rest)
+            shards=(runtime model export rest migrate)
             if [ "$CIRCLE_NODE_TOTAL" != "${#shards[@]}" ]; then
               echo "error: parallelism is $CIRCLE_NODE_TOTAL, but scripts/race-shard.sh has ${#shards[@]} shards" >&2
               exit 1
@@ -459,7 +459,10 @@ jobs:
               go test -v -race -pgo=off -timeout 30m ./tests/wasm
               go test -C tools -v -race -pgo=off -timeout 30m ./...
             else
-              go test -v -race -pgo=off -timeout 30m $pkgs
+              # tests/migrate alone runs 23-32 minutes under -race on this class, so its
+              # shard gets the Makefile's per-package timeout (see make test-shard).
+              timeout=30m; [ "$shard" = migrate ] && timeout=55m
+              go test -v -race -pgo=off -timeout "$timeout" $pkgs
             fi
           no_output_timeout: 30m
           environment:
@@ -483,11 +486,11 @@ jobs:
   # A second, race-free pass, because the profile the scan reads is written
   # with -coverpkg, which is too slow to instrument under -race. Serially the
   # instrumented suite overran the 60-minute job limit even on large, so it runs
-  # as the race test's four package shards, and go-coverage-merge joins them.
+  # as the race test's five package shards, and go-coverage-merge joins them.
   go-coverage:
     executor: go-executor
     resource_class: large
-    parallelism: 4
+    parallelism: 5
     steps:
       - checkout
       - go/load-cache
@@ -501,7 +504,7 @@ jobs:
       - run:
           name: Write this shard's coverage profile
           command: |
-            shards=(runtime model export rest)
+            shards=(runtime model export rest migrate)
             if [ "$CIRCLE_NODE_TOTAL" != "${#shards[@]}" ]; then
               echo "error: parallelism is $CIRCLE_NODE_TOTAL, but scripts/race-shard.sh has ${#shards[@]} shards" >&2
               exit 1
diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 9006ca33ba..4fa12dfeb1 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -83,12 +83,12 @@ jobs:
     name: Go race tests (${{ matrix.shard }})
     needs: changes
     if: needs.changes.outputs.go == 'true'
-    # The shards split the suite's slowest packages across runners so each gets its own job cap (see scripts/race-shard.sh).
-    # internal/exec/runtime alone outruns a job under -race, so it is two shards split by test name (see make test-shard).
+    # The shards split the suite's slowest packages across runners so each gets its own job cap (see scripts/race-shard.sh);
+    # internal/exec/runtime is two shards split by test name (see make test-shard) and tests/migrate, the next-longest, is one of its own.
     strategy:
       fail-fast: false
       matrix:
-        shard: [runtime, runtime-corpus, model, export, rest]
+        shard: [runtime, runtime-corpus, model, export, rest, migrate]
     runs-on: ubuntu-latest
     permissions:
       contents: read
@@ -297,7 +297,7 @@ jobs:
           set -euo pipefail
           profiles=(shards/coverage-*/coverage.txt)
           # One per race-tests shard.
-          if [ "${#profiles[@]}" -ne 5 ]; then echo "error: expected 5 shard profiles, found ${#profiles[@]}" >&2; exit 1; fi
+          if [ "${#profiles[@]}" -ne 6 ]; then echo "error: expected 6 shard profiles, found ${#profiles[@]}" >&2; exit 1; fi
           for f in "${profiles[@]}"; do
             [ "$(head -n 1 "$f")" = "mode: atomic" ] || { echo "error: $f is not an atomic-mode profile" >&2; exit 1; }
           done
diff --git a/AGENTS.md b/AGENTS.md
index ba4f8c48be..6d6d88c14c 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -29,7 +29,7 @@ make build            # build bin/sysml and bin/sysml-lsp (with version ldflags)
 make build-sysml      # REPL binary only
 make build-lsp        # LSP binary only
 make test             # full suite: go test -race -coverprofile ... ./...
-make test-shard SHARD=runtime   # one CI shard of the race suite (runtime|model|export|rest)
+make test-shard SHARD=runtime   # one CI shard of the race suite (runtime|runtime-corpus|model|export|rest|migrate)
 make test-short       # faster, no race detector
 make clean            # remove build artifacts
 ```
diff --git a/CHANGELOG.md b/CHANGELOG.md
index fcf9e37a6e..319b02354b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -444,6 +444,7 @@ release is described in [docs/project/releasing.md](docs/project/releasing.md).
 - The non-normative `OpenSysML Libraries/` extension libraries are now maintained upstream at [Open-MBEE/OpenSysML-Extensions-Library](https://github.com/Open-MBEE/OpenSysML-Extensions-Library); the bundled copy is pinned by `scripts/extension-libraries-pin.sh`, refreshed by `scripts/sync-extension-libraries.sh` (`make extension-libraries-sync`), checked for drift on every pull request (`make extension-libraries-check`), and carries `engine-contract.json` recording the qualified names the engine binds.
 
 - **Declare the bundled OpenSysML extension libraries as non-standard.** `DiagramLayout`, `IdentityMetadata`, `MigrationMetadata` and `SysMLValidation` were written `standard library package`, which both asserted membership of the normative Kernel/SysML libraries and drew a pilot warning (`User library packages should not be marked as standard`); they are project extensions and now read `library package`. RDF export no longer marks them `sysml:isStandard true`.
+- **`tests/migrate` is a race shard of its own.** The SysML v1 migrator's suite ran as part of the `rest` shard, where under `-race` it grew past 24 minutes on the pull-request runners and past the 30-minute package timeout on CircleCI's `develop` builds, failing every merge. `scripts/race-shard.sh migrate` names it, `make test-shard SHARD=migrate` and `make coverage-shard SHARD=migrate` run it, and both CI configurations run six race shards and five coverage shards.
 
 ### Deprecated
 
diff --git a/Makefile b/Makefile
index 528424f641..c6e1878859 100644
--- a/Makefile
+++ b/Makefile
@@ -73,7 +73,7 @@ TOOLS_DIR := tools
 COVERAGE_PACKAGES ?= ./...
 COVERAGE_TOOLS ?= ./...
 COVERAGE_PROFILE ?= coverage.txt
-COVERAGE_SHARDS := runtime model export rest
+COVERAGE_SHARDS := runtime model export rest migrate
 
 # The commands whose manual pages are generated and shipped, in section 1.
 COMMANDS := sysml sysml-lsp sysml-grpc sysml-jupyter-kernel
@@ -288,7 +288,7 @@ RACE_SHARD_SKIP := ^(TestTrainingExamplesSemanticErrors|TestCorpusGatesCacheStat
 RACE_RUNTIME_CORPUS := ^Test(ExploreWithIsExploreOverTheConformanceCorpus|CheckAgreesWithExploreOverTheConformanceCorpus|CheckWitnessesReplayOverTheConformanceCorpus|ExecutionConformance|ExecutionConformanceUnderPolicies)$$
 RACE_SHARD_TOOLS_SKIP := ^(TestSuiteRead|TestSuiteClassification|TestEmitSuite|TestSuiteClassificationReasons|TestSuiteLibraryCallsAreClassified|TestSuiteReadsControlAndObjectFlow|TestSuiteReadsClassifiers|TestSuiteReadsExceptionHandlers)$$
 
-test-shard: ## Run one CI shard of the race suite (SHARD=runtime|runtime-corpus|model|export|rest)
+test-shard: ## Run one CI shard of the race suite (SHARD=runtime|runtime-corpus|model|export|rest|migrate)
 	@echo "Running Go race tests, shard $(SHARD)..."
 	@# 55m per package; its job's ceiling is 60. Whole, internal/exec/runtime took 31-57 minutes
 	@# under -race on the CI runners, so it runs as two shards of about half that each.
@@ -324,14 +324,14 @@ coverage: ## Write the coverage profile the SonarCloud scan reads
 	python3 scripts/dedupe-coverage.py $(COVERAGE_PROFILE)
 	@go tool cover -func=$(COVERAGE_PROFILE) | tail -n 1
 
-coverage-shard: ## Write one CI shard's coverage profile, coverage-$(SHARD).txt (SHARD=runtime|model|export|rest)
+coverage-shard: ## Write one CI shard's coverage profile, coverage-$(SHARD).txt (SHARD=runtime|model|export|rest|migrate)
 	@# The race shards' packages; tests/wasm and the tools, which no race shard runs, go with runtime.
 	pkgs=$$(scripts/race-shard.sh $(SHARD)) && \
 	$(MAKE) --no-print-directory coverage COVERAGE_PROFILE=coverage-$(SHARD).txt \
 		COVERAGE_PACKAGES="$$(echo $$pkgs) $(if $(filter runtime,$(SHARD)),./tests/wasm)" \
 		COVERAGE_TOOLS="$(if $(filter runtime,$(SHARD)),./...)"
 
-coverage-merge: ## Merge the shard profiles coverage-runtime/model/export/rest.txt into coverage.txt
+coverage-merge: ## Merge the shard profiles coverage-runtime/model/export/rest/migrate.txt into coverage.txt
 	{ echo "mode: atomic"; for shard in $(COVERAGE_SHARDS); do tail -n +2 coverage-$$shard.txt || exit 1; done; } > coverage.txt
 	python3 scripts/dedupe-coverage.py coverage.txt
 	@go tool cover -func=coverage.txt | tail -n 1
diff --git a/scripts/race-shard.sh b/scripts/race-shard.sh
index 390424faf8..61c2d3e2a5 100755
--- a/scripts/race-shard.sh
+++ b/scripts/race-shard.sh
@@ -1,13 +1,13 @@
 #!/usr/bin/env bash
 # Prints the root-module package paths assigned to one race-test shard.
-# Usage: scripts/race-shard.sh runtime|runtime-corpus|model|export|rest
+# Usage: scripts/race-shard.sh runtime|runtime-corpus|model|export|rest|migrate
 # runtime and runtime-corpus are one package, split by test name in make test-shard.
 set -euo pipefail
 
 cd "$(dirname "$0")/.."
 
 if [[ $# -ne 1 ]]; then
-  echo "usage: scripts/race-shard.sh runtime|runtime-corpus|model|export|rest" >&2
+  echo "usage: scripts/race-shard.sh runtime|runtime-corpus|model|export|rest|migrate" >&2
   exit 2
 fi
 
@@ -20,14 +20,17 @@ smt="$module/internal/exec/smt"
 export="$module/tests/export"
 model="$module/tests/model"
 passes="$module/internal/check/passes"
+# tests/migrate runs the SysML v1 migrator over whole models and is the next-longest
+# package under -race after the runtime, so it is a shard of its own.
+migrate="$module/tests/migrate"
 # tests/wasm runs in the WebAssembly gate job, not a race shard.
 wasm="$module/tests/wasm"
-named_packages=("$runtime" "$workspace_model" "$corpus" "$smt" "$export" "$model" "$passes" "$wasm")
+named_packages=("$runtime" "$workspace_model" "$corpus" "$smt" "$export" "$model" "$passes" "$wasm" "$migrate")
 
 case "$shard" in
-  runtime|runtime-corpus|model|export|rest) ;;
+  runtime|runtime-corpus|model|export|rest|migrate) ;;
   *)
-    echo "usage: scripts/race-shard.sh runtime|runtime-corpus|model|export|rest" >&2
+    echo "usage: scripts/race-shard.sh runtime|runtime-corpus|model|export|rest|migrate" >&2
     exit 2
     ;;
 esac
@@ -50,6 +53,9 @@ case "$shard" in
   export)
     printf '%s\n' "$export" "$model" "$passes"
     ;;
+  migrate)
+    printf '%s\n' "$migrate"
+    ;;
   rest)
     while IFS= read -r package; do
       case " ${named_packages[*]} " in