diff --git a/README.md b/README.md
index 655686e..e090d6b 100644
--- a/README.md
+++ b/README.md
@@ -58,6 +58,14 @@ The final AMI is tagged with:
 - `NixSnapshotId`
 - `NixosSystemClosure`
 
+The publisher also writes SSM parameters that point to the AMI ID:
+
+- `/quixos/amis/<name>/<architecture>/recommended`
+- `/quixos/amis/<name>/<architecture>/by-builder-rev/<rev>`
+- `/quixos/amis/<name>/<architecture>/by-input-hash/<hash>`
+
+Central services read the `recommended` parameter by default.
+
 Do not deregister the AMI or delete either snapshot while runtime deployments
 use it.
 
@@ -69,6 +77,13 @@ List published AMIs and cross-reference qx-deploy runtime registry records:
 nix run ./tofu/ami-builder#ami-artifacts -- list
 ```
 
+Publish SSM parameters for an existing AMI, useful for AMIs created before SSM
+publication was added:
+
+```bash
+nix run ./tofu/ami-builder#ami-artifacts -- publish-ssm --ami-id ami-...
+```
+
 Delete an unused AMI and its root and `/nix` snapshots:
 
 ```bash
diff --git a/manage-amis.ts b/manage-amis.ts
index 8fff874..5f363b6 100644
--- a/manage-amis.ts
+++ b/manage-amis.ts
@@ -10,14 +10,15 @@ const repoRoot = process.env.QUIXOS_REPO_ROOT ?? path.resolve(sourceScriptDir, "
 const amiBuilderDir = process.env.QUIXOS_AMI_BUILDER_DIR ?? path.resolve(repoRoot, "tofu/ami-builder");
 const centralDir = path.resolve(amiBuilderDir, "../central");
 
-const usage = `Usage: nix run ./tofu/ami-builder#ami-artifacts -- <list|delete> [options]
+const usage = `Usage: nix run ./tofu/ami-builder#ami-artifacts -- <list|delete|publish-ssm> [options]
 
 Commands:
-  list                    List published AMI artifacts and deployment references
-  delete --ami-id <ami>   Deregister an AMI and delete its root and /nix snapshots
+  list                         List published AMI artifacts and deployment references
+  delete --ami-id <ami>        Deregister an AMI and delete its root and /nix snapshots
+  publish-ssm --ami-id <ami>   Publish an existing AMI into the SSM artifact registry
 
 Options:
-  --ami-id <ami>                  AMI to delete
+  --ami-id <ami>                  AMI to operate on
   --aws-region <region>          AWS region (default: AWS_REGION or us-west-2)
   --name <name>                  AMI project tag (default: nixos-zfs-ec2)
   --architecture <arm64|x86_64>  Filter by architecture
@@ -62,7 +63,7 @@ const parseArgs = (argv) => {
     console.error(usage.trimEnd());
     process.exit(command ? 0 : 1);
   }
-  if (command !== "list" && command !== "delete") {
+  if (command !== "list" && command !== "delete" && command !== "publish-ssm") {
     throw new Error(`Unknown command: ${command}\n\n${usage}`);
   }
 
@@ -287,6 +288,72 @@ const deleteArtifact = (state) => {
   }
 };
 
+const getImage = (state) => {
+  const result = awsJson([
+    "ec2",
+    "describe-images",
+    "--region",
+    state.awsRegion,
+    "--owners",
+    "self",
+    "--image-ids",
+    state.amiId,
+  ]);
+  const image = result?.Images?.[0];
+  if (!image) {
+    throw new Error(`AMI not found: ${state.amiId}`);
+  }
+  return image;
+};
+
+const putSsmParameter = (state, name, value) => {
+  run("aws", [
+    "ssm",
+    "put-parameter",
+    "--region",
+    state.awsRegion,
+    "--name",
+    name,
+    "--type",
+    "String",
+    "--value",
+    value,
+    "--overwrite",
+  ]);
+};
+
+const publishSsmArtifact = (state) => {
+  if (!state.amiId) {
+    throw new Error("Missing --ami-id");
+  }
+
+  const image = getImage(state);
+  const tags = amiTags(image);
+  const architecture = tags.Architecture ?? image.Architecture ?? "";
+  const builderGitRev = tags.BuilderGitRev ?? "";
+  const inputHash = tags.InputHash ?? "";
+  if (!architecture) {
+    throw new Error(`AMI ${state.amiId} is missing Architecture metadata`);
+  }
+  if (!builderGitRev) {
+    throw new Error(`AMI ${state.amiId} is missing BuilderGitRev tag`);
+  }
+  if (!inputHash) {
+    throw new Error(`AMI ${state.amiId} is missing InputHash tag`);
+  }
+
+  const prefix = `/quixos/amis/${state.name}/${architecture}`;
+  const parameters = [
+    `${prefix}/recommended`,
+    `${prefix}/by-builder-rev/${builderGitRev}`,
+    `${prefix}/by-input-hash/${inputHash}`,
+  ];
+  for (const parameter of parameters) {
+    console.error(`Writing ${parameter} = ${state.amiId}`);
+    putSsmParameter(state, parameter, state.amiId);
+  }
+};
+
 const main = () => {
   const state = parseArgs(process.argv.slice(2));
   requireCommand("aws");
@@ -296,6 +363,10 @@ const main = () => {
     listArtifacts(state);
     return;
   }
+  if (state.command === "publish-ssm") {
+    publishSsmArtifact(state);
+    return;
+  }
   deleteArtifact(state);
 };
 
diff --git a/publish-ami.sh b/publish-ami.sh
index 098d0c7..61e57a7 100755
--- a/publish-ami.sh
+++ b/publish-ami.sh
@@ -271,6 +271,20 @@ aws ec2 create-tags \
     "Key=RootSnapshotId,Value=${root_snapshot_id}" \
     "Key=NixSnapshotId,Value=${nix_snapshot_id}"
 
+ssm_ami_prefix="/quixos/amis/${name}/${architecture}"
+for ssm_ami_parameter_name in \
+  "${ssm_ami_prefix}/recommended" \
+  "${ssm_ami_prefix}/by-builder-rev/${builder_git_rev}" \
+  "${ssm_ami_prefix}/by-input-hash/${input_hash}"
+do
+  aws ssm put-parameter \
+    --region "$aws_region" \
+    --name "$ssm_ami_parameter_name" \
+    --type String \
+    --value "$image_id" \
+    --overwrite >/dev/null
+done
+
 aws ec2 deregister-image --region "$aws_region" --image-id "$capture_image_id" >/dev/null
 
 jq -n \
@@ -285,6 +299,7 @@ jq -n \
   --arg rootDeviceName "$root_device_name" \
   --arg nixDeviceName "$nix_device_name" \
   --arg nixPool "$nix_pool" \
+  --arg ssmRecommendedParameter "${ssm_ami_prefix}/recommended" \
   '{
     architecture: $architecture,
     system: $system,
@@ -296,7 +311,8 @@ jq -n \
     nixSnapshotId: $nixSnapshotId,
     rootDeviceName: $rootDeviceName,
     nixDeviceName: $nixDeviceName,
-    nixPool: $nixPool
+    nixPool: $nixPool,
+    ssmRecommendedParameter: $ssmRecommendedParameter
   }' > artifact.json
 
 if [ "$keep_builder" = false ]; then
@@ -313,3 +329,4 @@ if [ "$keep_builder" = false ]; then
 fi
 
 echo "Published AMI: $image_id"
+echo "Published SSM parameter: ${ssm_ami_prefix}/recommended"