diff --git a/scripts/artifact-registry-ssh-timeout-contract-test.ts b/scripts/artifact-registry-ssh-timeout-contract-test.ts
index 640da462..e16301c2 100644
--- a/scripts/artifact-registry-ssh-timeout-contract-test.ts
+++ b/scripts/artifact-registry-ssh-timeout-contract-test.ts
@@ -16,7 +16,7 @@ assertCondition(source.includes("downloadRemoteFile(options, remoteArchive, loca
 assertCondition(source.includes("runRemoteScriptBackground(options, remoteScript"), "remote docker save must run as a background job");
 assertCondition(source.includes('runRemoteScriptBackground(options, deployScript, Math.max(options.timeoutMs, 420_000), "d601-k3s-deploy")'), "D601 k3s deploy must use background polling");
 assertCondition(source.includes('"ssh",\n    options.providerId,\n    "download"'), "download helper must route through UniDesk ssh download");
-assertCondition(downloadRemoteFileSource.includes('"--chunk-bytes",\n    "64000"'), "artifact ssh download must use a mid-size bounded chunk, not the largest chunk");
+assertCondition(downloadRemoteFileSource.includes('"--chunk-bytes",\n    "45000"'), "artifact ssh download chunk must keep base64 stdout below the provider bridge truncation boundary");
 assertCondition(downloadRemoteFileSource.includes("tee -a") && downloadRemoteFileSource.includes("UNIDESK_JOB_STDERR_FILE"), "artifact ssh download must stream progress stderr into async job logs");
 assertCondition(source.includes("UNIDESK_SSH_CLIENT_TOKEN") && source.includes("UNIDESK_SSH_CLIENT_ROUTE_ALLOWLIST"), "dev frontend artifact deploy must sync scoped ssh runtime keys");
 
@@ -27,7 +27,7 @@ console.log(JSON.stringify({
     "no docker-save stdout stream over ssh",
     "compose artifact uses verified ssh download",
     "remote docker save and k3s deploy use background polling",
-    "artifact downloads use a mid-size bounded ssh chunk",
+    "artifact downloads keep base64 stdout below the provider bridge truncation boundary",
     "artifact download progress is visible in async job stderr",
     "dev frontend artifact deploy syncs scoped ssh runtime keys"
   ]
diff --git a/scripts/src/artifact-registry.ts b/scripts/src/artifact-registry.ts
index ebcde892..8ec88179 100644
--- a/scripts/src/artifact-registry.ts
+++ b/scripts/src/artifact-registry.ts
@@ -1678,7 +1678,7 @@ function downloadRemoteFile(options: ArtifactRegistryOptions, remotePath: string
     options.providerId,
     "download",
     "--chunk-bytes",
-    "64000",
+    "45000",
     remotePath,
     localPath,
   ];