diff --git a/modules/meshstack/noop/buildingblock/README.md b/modules/meshstack/noop/buildingblock/README.md
index eb9e9c60..e8829278 100644
--- a/modules/meshstack/noop/buildingblock/README.md
+++ b/modules/meshstack/noop/buildingblock/README.md
@@ -26,6 +26,7 @@ Use it to:
 | `sensitive_yaml`        | `CODE`               | `STATIC` (sensitive) | Encrypted YAML/JSON value, decrypted at runtime                                                                    |
 | `static`                | `STRING`             | `STATIC`             | A platform-engineer-defined string constant                                                                        |
 | `static_code`           | `CODE`               | `STATIC`             | A platform-engineer-defined map                                                                                    |
+| `tag_value`             | `CODE`               | `TAG`                | Value of a meshStack tag, read from the target object rather than typed in by a user                               |
 | `flag`                  | `BOOLEAN`            | `USER_INPUT`         | Boolean flag chosen by the user                                                                                    |
 | `num`                   | `INTEGER`            | `USER_INPUT`         | Integer chosen by the user                                                                                         |
 | `text`                  | `STRING`             | `USER_INPUT`         | Free-text string from the user                                                                                     |
@@ -78,6 +79,7 @@ No modules.
 | <a name="input_single_select"></a> [single\_select](#input\_single\_select) | n/a | `string` | n/a | yes |
 | <a name="input_static"></a> [static](#input\_static) | n/a | `string` | n/a | yes |
 | <a name="input_static_code"></a> [static\_code](#input\_static\_code) | n/a | `map(string)` | n/a | yes |
+| <a name="input_tag_value"></a> [tag\_value](#input\_tag\_value) | n/a | `list(string)` | n/a | yes |
 | <a name="input_text"></a> [text](#input\_text) | n/a | `string` | n/a | yes |
 | <a name="input_user_permissions"></a> [user\_permissions](#input\_user\_permissions) | n/a | <pre>list(object({<br/>    meshIdentifier = string<br/>    username       = string<br/>    firstName      = string<br/>    lastName       = string<br/>    email          = string<br/>    euid           = string<br/>    roles          = list(string)<br/>  }))</pre> | n/a | yes |
 | <a name="input_user_permissions_json"></a> [user\_permissions\_json](#input\_user\_permissions\_json) | n/a | `string` | n/a | yes |
@@ -102,6 +104,7 @@ No modules.
 | <a name="output_static"></a> [static](#output\_static) | n/a |
 | <a name="output_static_code"></a> [static\_code](#output\_static\_code) | n/a |
 | <a name="output_summary"></a> [summary](#output\_summary) | n/a |
+| <a name="output_tag_value"></a> [tag\_value](#output\_tag\_value) | n/a |
 | <a name="output_text"></a> [text](#output\_text) | n/a |
 | <a name="output_user_permissions"></a> [user\_permissions](#output\_user\_permissions) | n/a |
 | <a name="output_user_permissions_json"></a> [user\_permissions\_json](#output\_user\_permissions\_json) | n/a |
diff --git a/modules/meshstack/noop/buildingblock/outputs.tf b/modules/meshstack/noop/buildingblock/outputs.tf
index e606ea2b..5a49de02 100644
--- a/modules/meshstack/noop/buildingblock/outputs.tf
+++ b/modules/meshstack/noop/buildingblock/outputs.tf
@@ -27,6 +27,10 @@ output "static_code" {
   value = var.static_code
 }
 
+output "tag_value" {
+  value = var.tag_value
+}
+
 output "flag" {
   value = var.flag
 }
@@ -113,6 +117,7 @@ output "debug_input_variables_json" {
     multi_select_json     = var.multi_select_json
     static                = var.static
     static_code           = var.static_code
+    tag_value             = var.tag_value
     user_permissions      = var.user_permissions
     user_permissions_json = var.user_permissions_json
   })
diff --git a/modules/meshstack/noop/buildingblock/variables.tf b/modules/meshstack/noop/buildingblock/variables.tf
index 5c562a81..d403ca46 100644
--- a/modules/meshstack/noop/buildingblock/variables.tf
+++ b/modules/meshstack/noop/buildingblock/variables.tf
@@ -27,6 +27,12 @@ variable "static_code" {
   type = map(string)
 }
 
+variable "tag_value" {
+  # meshStack sends a TAG input as a JSON array of strings; a tag with no value resolves to null.
+  type     = list(string)
+  nullable = true
+}
+
 variable "flag" {
   type = bool
 }
diff --git a/modules/meshstack/noop/e2e/main.tf b/modules/meshstack/noop/e2e/main.tf
index d27b1d0d..43ae66e1 100644
--- a/modules/meshstack/noop/e2e/main.tf
+++ b/modules/meshstack/noop/e2e/main.tf
@@ -8,6 +8,30 @@ variable "test_context" {
   nullable = false
 }
 
+# A tag input reads its value from an existing meshStack tag, so the e2e test provisions its own
+# tag definition and sets it on the test workspace to exercise the input end-to-end. It cannot be
+# destroyed while the building block definition below reads it, so referencing its `spec.key` from
+# the module's `tag_key` input (and the workspace tag depending on the definition) gets destroy
+# order right on its own.
+resource "meshstack_tag_definition" "noop_e2e" {
+  spec = {
+    target_kind  = "meshWorkspace"
+    key          = "noop-e2e-tag-${var.test_context.name_suffix}"
+    display_name = "NoOp E2E Tag"
+    value_type   = { string = {} }
+  }
+}
+
+resource "meshstack_workspace_tag" "noop_e2e" {
+  metadata = {
+    workspace_identifier = var.test_context.workspace
+    key                  = meshstack_tag_definition.noop_e2e.spec.key
+  }
+  spec = {
+    values = ["e2e-tag-value"]
+  }
+}
+
 module "noop" {
   source = "../"
   meshstack = {
@@ -18,9 +42,14 @@ module "noop" {
     git_ref   = var.test_context.hub_git_ref
     bbd_draft = true
   }
+  tag_object = "WORKSPACE"
+  tag_key    = meshstack_tag_definition.noop_e2e.spec.key
 }
 
 resource "meshstack_building_block" "this" {
+  # ensures the tag has a value before the building block run reads it
+  depends_on = [meshstack_workspace_tag.noop_e2e]
+
   wait_for_completion = true
   spec = {
     building_block_definition_version_ref = module.noop.building_block_definition.version_ref
@@ -40,6 +69,7 @@ resource "meshstack_building_block" "this" {
       single_select     = { value = jsonencode("single1") }
       multi_select      = { value = jsonencode(["multi1", "multi2"]) }
       multi_select_json = { value = jsonencode(["multi2", "multi1"]) }
+      # tag_value       = <nothing>  -> TAG-assigned inputs are read by meshStack from the workspace tag, not supplied here.
     }
   }
 }
diff --git a/modules/meshstack/noop/e2e/tests/building_block_noop_hub.debug_input_variables_json.expected.json b/modules/meshstack/noop/e2e/tests/building_block_noop_hub.debug_input_variables_json.expected.json
index 444d5eb3..28028f6d 100644
--- a/modules/meshstack/noop/e2e/tests/building_block_noop_hub.debug_input_variables_json.expected.json
+++ b/modules/meshstack/noop/e2e/tests/building_block_noop_hub.debug_input_variables_json.expected.json
@@ -14,5 +14,6 @@
     "static_code": {
         "some":"code"
     },
+    "tag_value": ["e2e-tag-value"],
     "text":"Hello, World!"
 }
diff --git a/modules/meshstack/noop/e2e/tests/building_block_noop_hub.tftest.hcl b/modules/meshstack/noop/e2e/tests/building_block_noop_hub.tftest.hcl
index d18e657c..2cae4246 100644
--- a/modules/meshstack/noop/e2e/tests/building_block_noop_hub.tftest.hcl
+++ b/modules/meshstack/noop/e2e/tests/building_block_noop_hub.tftest.hcl
@@ -31,6 +31,13 @@ run "building_block_noop_hub" {
     error_message = "noop hub building block expected output resource_url to be 'https://hub.meshcloud.io/modules/meshstack/noop', got ${jsondecode(meshstack_building_block.this.status.outputs["resource_url"].value)}"
   }
 
+  assert {
+    # tag_value is sourced from the meshstack_workspace_tag set up in e2e/main.tf, not from the
+    # building block's own inputs.
+    condition     = jsondecode(meshstack_building_block.this.status.outputs["tag_value"].value) == ["e2e-tag-value"]
+    error_message = "noop hub building block expected output tag_value to be [\"e2e-tag-value\"], got ${jsondecode(meshstack_building_block.this.status.outputs["tag_value"].value)}"
+  }
+
   assert {
     condition = (
       jsondecode(meshstack_building_block.this.status.outputs["summary"].value)
diff --git a/modules/meshstack/noop/meshstack_integration.tf b/modules/meshstack/noop/meshstack_integration.tf
index eeb7dd7f..f4b73292 100644
--- a/modules/meshstack/noop/meshstack_integration.tf
+++ b/modules/meshstack/noop/meshstack_integration.tf
@@ -7,6 +7,18 @@ variable "runner_ref" {
   description = "Optional reference to a meshStack building block runner. When set, building block runs are dispatched to this custom runner. Obtain the value from the backplane module's `runner_ref` output."
 }
 
+variable "tag_object" {
+  type        = string
+  default     = "WORKSPACE"
+  description = "The meshStack object kind the `tag_value` input reads its value from. A WORKSPACE_LEVEL building block definition (like this one) can only read WORKSPACE tags; TENANT_LEVEL definitions can also read PROJECT, PAYMENT_METHOD, or LANDING_ZONE."
+}
+
+variable "tag_key" {
+  type        = string
+  default     = "business-unit"
+  description = "Key of an existing meshStack tag definition (target_kind meshWorkspace) that the `tag_value` input reads its value from. The tag definition must already exist on the target meshStack instance."
+}
+
 variable "meshstack" {
   type = object({
     owning_workspace_identifier = string
@@ -177,6 +189,12 @@ resource "meshstack_building_block_definition" "this" {
         display_name    = "Static Code"
         type            = "CODE"
       }
+      tag_value = {
+        assignment_type = "TAG"
+        argument        = jsonencode("${var.tag_object}.${var.tag_key}")
+        display_name    = "Tag Value"
+        type            = "CODE"
+      }
       text = {
         assignment_type = "USER_INPUT"
         default_value   = jsonencode("")
@@ -220,6 +238,17 @@ resource "meshstack_building_block_definition" "this" {
         display_name    = "Static Code"
         type            = "CODE"
       }
+      # We need to wait for TF provider release to make this work
+      # tag_value = {
+      #   assignment_type = "NONE"
+      #   display_name    = "Tag Value"
+      #   type            = "CODE"
+      # }
+      tag_value = {
+        assignment_type = "NONE"
+        display_name    = "Tag Value"
+        type            = "CODE"
+      }
       resource_url = {
         assignment_type = "RESOURCE_URL"
         display_name    = "Resource URL"
@@ -250,7 +279,7 @@ terraform {
   required_providers {
     meshstack = {
       source  = "meshcloud/meshstack"
-      version = ">= 0.21.0"
+      version = ">= 0.25.2"
     }
   }
 }