diff --git a/packages/conformance/README.md b/packages/conformance/README.md
index 8ebb94b997..aa0d652eb1 100644
--- a/packages/conformance/README.md
+++ b/packages/conformance/README.md
@@ -49,3 +49,21 @@ To run the full Solidity -> SolDB resources path, set `ETHDEBUG_CONFORMANCE_SOLC
 and `ETHDEBUG_CONFORMANCE_SOLDB`. If `anvil` and `cast` are on `PATH`, the
 SolDB breakpoint test runs as well; the executable paths can be overridden with
 `ETHDEBUG_CONFORMANCE_ANVIL` and `ETHDEBUG_CONFORMANCE_CAST`.
+
+## Expected failures
+
+When the format and a tool disagree, the tests do not wait for the tool. This
+applies whichever side moved: a format change that a tool does not follow yet,
+or a tool that does not follow the format. Each such divergence, per tool, goes
+through these steps:
+
+1. Open one tracking issue on ethdebug/format. It says what the tool does and
+   where in the tool's code.
+2. Add a shim and a tripwire to the test. The shim makes the test pass now. The
+   tripwire fails once the tool conforms, and its message names the shim and
+   the issue. When the format change causes the divergence, the shim lands in
+   the same PR as the format change, so main stays green.
+3. When the tripwire fires, one PR removes the shim and the tripwire and closes
+   the issue.
+
+Prefer a shim in the test to a pinned tool version.
diff --git a/packages/conformance/test/conformance.test.ts b/packages/conformance/test/conformance.test.ts
index 07484902c6..b4805902c8 100644
--- a/packages/conformance/test/conformance.test.ts
+++ b/packages/conformance/test/conformance.test.ts
@@ -198,6 +198,24 @@ function withSolcTildeVocabulary(artifact: EthdebugArtifact): EthdebugArtifact {
   };
 }
 
+// Expected failure (#406): SolDB drops the `ethdebug` stamp from the
+// resources object it reads. Until SolDB keeps it, the SolDB tests compare
+// its resources with a copy of solc's resources without the stamp, so the
+// rest of resources is still checked. The check below fails once SolDB
+// keeps the stamp; then remove this function and compare the resources as
+// they are.
+function withoutResourcesStamp(
+  resources: EthdebugArtifact["resources"],
+  soldbResources: { ethdebug?: unknown },
+) {
+  expect(
+    soldbResources.ethdebug,
+    "SolDB now keeps the resources stamp; remove withoutResourcesStamp (#406)",
+  ).toBeUndefined();
+  const { ethdebug: _, ...rest } = resources ?? {};
+  return rest;
+}
+
 function validArtifact(
   overrides: Partial<EthdebugArtifact> = {},
 ): EthdebugArtifact {
@@ -276,7 +294,9 @@ describe("@ethdebug/conformance", () => {
       expect(result.exitCode).toBe(0);
       const json = result.json as any;
       expect(json.contracts[0].name).toBe("Counter");
-      expect(json.contracts[0].resources).toEqual(artifact.resources);
+      expect(json.contracts[0].resources).toEqual(
+        withoutResourcesStamp(artifact.resources, json.contracts[0].resources),
+      );
       expect(
         json.contracts[0].resources.compilation.sources[0].contents,
       ).toContain("contract Counter");