diff --git a/registry/coder/.images/aws-ec2-instance-type.png b/registry/coder/.images/aws-ec2-instance-type.png
new file mode 100644
index 000000000..fdb3175bd
Binary files /dev/null and b/registry/coder/.images/aws-ec2-instance-type.png differ
diff --git a/registry/coder/modules/aws-ec2-instance-type/.scripts/update.sh b/registry/coder/modules/aws-ec2-instance-type/.scripts/update.sh
new file mode 100755
index 000000000..ea440d2ef
--- /dev/null
+++ b/registry/coder/modules/aws-ec2-instance-type/.scripts/update.sh
@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+
+# Regenerates instance-types.json from the AWS EC2 API. Edit the families list
+# below, then run this script and commit the result. Sizes within each family
+# are enumerated from AWS, so a newly released size is picked up automatically.
+#
+# Requires the AWS CLI with credentials allowed to call
+# ec2:DescribeInstanceTypes. Override the query region with AWS_REGION
+# (default us-east-1, which offers every family in the list).
+
+set -euo pipefail
+
+script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+output_file="$script_dir/../instance-types.json"
+region="${AWS_REGION:-us-east-1}"
+
+# Instance families to offer. general: t3/t4g/m5/m7g, compute: c5, memory: r5,
+# storage: i3, gpu: g4dn.
+families=(t3 t4g m5 m7g c5 r5 i3 g4dn)
+
+if ! command -v aws > /dev/null 2>&1; then
+  echo "error: aws CLI not found; install and configure it first" >&2
+  exit 1
+fi
+
+# Turn the families into an instance-type wildcard filter, e.g. "t3.*,m5.*".
+family_filter=""
+for family in "${families[@]}"; do
+  family_filter="${family_filter:+$family_filter,}$family.*"
+done
+
+tmp="$(mktemp)"
+trap 'rm -f "$tmp"' EXIT
+
+# bare-metal=false keeps the catalog to virtualized sizes; .metal instances are
+# not sensible workspace defaults. The AWS CLI paginates automatically.
+aws ec2 describe-instance-types \
+  --region "$region" \
+  --filters "Name=instance-type,Values=${family_filter}" "Name=bare-metal,Values=false" \
+  --output json \
+  --query 'sort_by(InstanceTypes, &MemoryInfo.SizeInMiB)[].{type: InstanceType, vcpus: VCpuInfo.DefaultVCpus, memory_mib: MemoryInfo.SizeInMiB, gpus: (GpuInfo.Gpus[0].Count || `0`), arch: ProcessorInfo.SupportedArchitectures[-1]}' \
+  > "$tmp"
+
+mv "$tmp" "$output_file"
+
+# AWS CLI emits 4-space JSON; match the repo's prettier formatting.
+if command -v bun > /dev/null 2>&1; then
+  bun x prettier --write "$output_file" > /dev/null
+else
+  echo "note: bun not found; run 'bun run fmt' before committing $output_file" >&2
+fi
+
+echo "Updated $output_file"
diff --git a/registry/coder/modules/aws-ec2-instance-type/README.md b/registry/coder/modules/aws-ec2-instance-type/README.md
new file mode 100644
index 000000000..024bab6fc
--- /dev/null
+++ b/registry/coder/modules/aws-ec2-instance-type/README.md
@@ -0,0 +1,121 @@
+---
+display_name: AWS EC2 Instance Type
+description: A parameter with human readable AWS EC2 instance type names
+icon: ../../../../.icons/aws.svg
+verified: false
+tags: [helper, parameter, instances, aws]
+---
+
+# AWS EC2 Instance Type
+
+A parameter with common AWS EC2 instance types, filtered by instance family.
+Each option is labeled with its vCPU, RAM, and architecture so developers can
+select the machine that best fits their workspace.
+
+```tf
+module "aws_ec2_instance_type" {
+  count   = data.coder_workspace.me.start_count
+  source  = "registry.coder.com/coder/aws-ec2-instance-type/coder"
+  version = "1.0.0"
+  default = "t3.micro"
+}
+
+resource "aws_instance" "dev" {
+  instance_type = module.aws_ec2_instance_type[0].value
+  # ...
+}
+```
+
+![AWS EC2 Instance Type parameter](../../.images/aws-ec2-instance-type.png)
+
+## Examples
+
+### Choose instance families
+
+By default only the `t3` family is offered. Pass `include` to expose more
+families and preselect one:
+
+```tf
+module "aws_ec2_instance_type" {
+  count   = data.coder_workspace.me.start_count
+  source  = "registry.coder.com/coder/aws-ec2-instance-type/coder"
+  version = "1.0.0"
+  include = ["t3", "m5", "c5"]
+  default = "m5.large"
+}
+```
+
+The bundled catalog covers the `t3`, `t4g`, `m5`, `m7g`, `c5`, `r5`, `i3`, and
+`g4dn` families.
+
+### Customize labels and tooltips
+
+Each option is labeled with its specs and architecture (for example
+`2 vCPU, 4 GiB RAM (amd64)`) and shows the instance type as a tooltip. Override
+either per instance type:
+
+```tf
+module "aws_ec2_instance_type" {
+  count   = data.coder_workspace.me.start_count
+  source  = "registry.coder.com/coder/aws-ec2-instance-type/coder"
+  version = "1.0.0"
+  default = "t3.medium"
+
+  custom_metadata = {
+    "t3.medium" = {
+      name        = "Standard workspace"
+      description = "Recommended default"
+    }
+  }
+}
+```
+
+### Architecture-aware provisioning
+
+The `instances` output maps every instance type ID to its metadata, including architecture fields. Look up the selected value to configure the agent and pick a matching AMI:
+
+```tf
+module "aws_ec2_instance_type" {
+  source  = "registry.coder.com/coder/aws-ec2-instance-type/coder"
+  version = "1.0.0"
+}
+
+locals {
+  selected = module.aws_ec2_instance_type.instances[module.aws_ec2_instance_type.value]
+}
+
+resource "coder_agent" "dev" {
+  arch = local.selected.coder_arch # amd64 or arm64
+  os   = "linux"
+}
+
+data "aws_ami" "workspace" {
+  most_recent = true
+  owners      = ["amazon"]
+
+  filter {
+    name   = "architecture"
+    values = [local.selected.arch] # x86_64 or arm64
+  }
+}
+```
+
+### Use the catalog without a parameter
+
+Set `create_parameter = false` to skip the picker (for example when the template pins the size) while still using the `instances` catalog:
+
+```tf
+module "aws_ec2_instance_type" {
+  source           = "registry.coder.com/coder/aws-ec2-instance-type/coder"
+  version          = "1.0.0"
+  create_parameter = false
+  default          = "t4g.large"
+}
+```
+
+## Related templates
+
+For a complete AWS EC2 template, see the following examples in the [Coder Registry](https://registry.coder.com/).
+
+- [AWS EC2 (Linux)](https://registry.coder.com/templates/aws-linux)
+- [AWS EC2 (Windows)](https://registry.coder.com/templates/aws-windows)
diff --git a/registry/coder/modules/aws-ec2-instance-type/instance-types.json b/registry/coder/modules/aws-ec2-instance-type/instance-types.json
new file mode 100644
index 000000000..0665809e5
--- /dev/null
+++ b/registry/coder/modules/aws-ec2-instance-type/instance-types.json
@@ -0,0 +1,408 @@
+[
+  {
+    "type": "t3.nano",
+    "vcpus": 2,
+    "memory_mib": 512,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "t4g.nano",
+    "vcpus": 2,
+    "memory_mib": 512,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "t3.micro",
+    "vcpus": 2,
+    "memory_mib": 1024,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "t4g.micro",
+    "vcpus": 2,
+    "memory_mib": 1024,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "t3.small",
+    "vcpus": 2,
+    "memory_mib": 2048,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "t4g.small",
+    "vcpus": 2,
+    "memory_mib": 2048,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "c5.large",
+    "vcpus": 2,
+    "memory_mib": 4096,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m7g.medium",
+    "vcpus": 1,
+    "memory_mib": 4096,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "t3.medium",
+    "vcpus": 2,
+    "memory_mib": 4096,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "t4g.medium",
+    "vcpus": 2,
+    "memory_mib": 4096,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "c5.xlarge",
+    "vcpus": 4,
+    "memory_mib": 8192,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m5.large",
+    "vcpus": 2,
+    "memory_mib": 8192,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m7g.large",
+    "vcpus": 2,
+    "memory_mib": 8192,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "t3.large",
+    "vcpus": 2,
+    "memory_mib": 8192,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "t4g.large",
+    "vcpus": 2,
+    "memory_mib": 8192,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "i3.large",
+    "vcpus": 2,
+    "memory_mib": 15616,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "c5.2xlarge",
+    "vcpus": 8,
+    "memory_mib": 16384,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "g4dn.xlarge",
+    "vcpus": 4,
+    "memory_mib": 16384,
+    "gpus": 1,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m5.xlarge",
+    "vcpus": 4,
+    "memory_mib": 16384,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m7g.xlarge",
+    "vcpus": 4,
+    "memory_mib": 16384,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "r5.large",
+    "vcpus": 2,
+    "memory_mib": 16384,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "t3.xlarge",
+    "vcpus": 4,
+    "memory_mib": 16384,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "t4g.xlarge",
+    "vcpus": 4,
+    "memory_mib": 16384,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "i3.xlarge",
+    "vcpus": 4,
+    "memory_mib": 31232,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "c5.4xlarge",
+    "vcpus": 16,
+    "memory_mib": 32768,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "g4dn.2xlarge",
+    "vcpus": 8,
+    "memory_mib": 32768,
+    "gpus": 1,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m5.2xlarge",
+    "vcpus": 8,
+    "memory_mib": 32768,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m7g.2xlarge",
+    "vcpus": 8,
+    "memory_mib": 32768,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "r5.xlarge",
+    "vcpus": 4,
+    "memory_mib": 32768,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "t3.2xlarge",
+    "vcpus": 8,
+    "memory_mib": 32768,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "t4g.2xlarge",
+    "vcpus": 8,
+    "memory_mib": 32768,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "i3.2xlarge",
+    "vcpus": 8,
+    "memory_mib": 62464,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "g4dn.4xlarge",
+    "vcpus": 16,
+    "memory_mib": 65536,
+    "gpus": 1,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m5.4xlarge",
+    "vcpus": 16,
+    "memory_mib": 65536,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m7g.4xlarge",
+    "vcpus": 16,
+    "memory_mib": 65536,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "r5.2xlarge",
+    "vcpus": 8,
+    "memory_mib": 65536,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "c5.9xlarge",
+    "vcpus": 36,
+    "memory_mib": 73728,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "c5.12xlarge",
+    "vcpus": 48,
+    "memory_mib": 98304,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "i3.4xlarge",
+    "vcpus": 16,
+    "memory_mib": 124928,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "g4dn.8xlarge",
+    "vcpus": 32,
+    "memory_mib": 131072,
+    "gpus": 1,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m5.8xlarge",
+    "vcpus": 32,
+    "memory_mib": 131072,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m7g.8xlarge",
+    "vcpus": 32,
+    "memory_mib": 131072,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "r5.4xlarge",
+    "vcpus": 16,
+    "memory_mib": 131072,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "c5.18xlarge",
+    "vcpus": 72,
+    "memory_mib": 147456,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "c5.24xlarge",
+    "vcpus": 96,
+    "memory_mib": 196608,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "g4dn.12xlarge",
+    "vcpus": 48,
+    "memory_mib": 196608,
+    "gpus": 4,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m5.12xlarge",
+    "vcpus": 48,
+    "memory_mib": 196608,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m7g.12xlarge",
+    "vcpus": 48,
+    "memory_mib": 196608,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "i3.8xlarge",
+    "vcpus": 32,
+    "memory_mib": 249856,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "g4dn.16xlarge",
+    "vcpus": 64,
+    "memory_mib": 262144,
+    "gpus": 1,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m5.16xlarge",
+    "vcpus": 64,
+    "memory_mib": 262144,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m7g.16xlarge",
+    "vcpus": 64,
+    "memory_mib": 262144,
+    "gpus": 0,
+    "arch": "arm64"
+  },
+  {
+    "type": "r5.8xlarge",
+    "vcpus": 32,
+    "memory_mib": 262144,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "m5.24xlarge",
+    "vcpus": 96,
+    "memory_mib": 393216,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "r5.12xlarge",
+    "vcpus": 48,
+    "memory_mib": 393216,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "i3.16xlarge",
+    "vcpus": 64,
+    "memory_mib": 499712,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "r5.16xlarge",
+    "vcpus": 64,
+    "memory_mib": 524288,
+    "gpus": 0,
+    "arch": "x86_64"
+  },
+  {
+    "type": "r5.24xlarge",
+    "vcpus": 96,
+    "memory_mib": 786432,
+    "gpus": 0,
+    "arch": "x86_64"
+  }
+]
diff --git a/registry/coder/modules/aws-ec2-instance-type/main.tf b/registry/coder/modules/aws-ec2-instance-type/main.tf
new file mode 100644
index 000000000..5debffd82
--- /dev/null
+++ b/registry/coder/modules/aws-ec2-instance-type/main.tf
@@ -0,0 +1,151 @@
+terraform {
+  required_version = ">= 1.3"
+
+  required_providers {
+    coder = {
+      source  = "coder/coder"
+      version = ">= 0.12"
+    }
+  }
+}
+
+variable "display_name" {
+  description = "The display name of the parameter."
+  type        = string
+  default     = "AWS EC2 Instance Type"
+}
+
+variable "description" {
+  description = "The description of the parameter."
+  type        = string
+  default     = "Select the EC2 instance type to use for the workspace. See https://aws.amazon.com/ec2/instance-types/ for details."
+}
+
+variable "default" {
+  description = "The default instance type to preselect (must belong to an included family), or the fixed value returned when create_parameter is false."
+  type        = string
+  default     = ""
+}
+
+variable "create_parameter" {
+  description = "Whether to create the built-in coder_parameter. Set to false to skip the picker and return default while still exposing the instances catalog."
+  type        = bool
+  default     = true
+}
+
+variable "mutable" {
+  description = "Whether the parameter can be changed after creation."
+  type        = bool
+  default     = false
+}
+
+variable "custom_metadata" {
+  description = "Per instance type overrides keyed by instance type ID. name replaces the generated \"vCPU / RAM / arch\" label; description replaces the instance-type tooltip."
+  type = map(object({
+    name        = optional(string)
+    description = optional(string)
+  }))
+  default = {}
+}
+
+variable "include" {
+  description = "Instance families to offer in the picker, e.g. [\"t3\", \"m5\", \"c5\"]. Defaults to t3."
+  type        = list(string)
+  default     = ["t3"]
+
+  validation {
+    condition     = length(var.include) > 0
+    error_message = "include must list at least one instance family, e.g. [\"t3\"]."
+  }
+}
+
+variable "coder_parameter_order" {
+  description = "The order determines the position of a template parameter in the UI/CLI presentation. The lowest order is shown first and parameters with equal order are sorted by name (ascending order)."
+  type        = number
+  default     = null
+}
+
+locals {
+  # Specs come straight from `aws ec2 describe-instance-types` (regenerate with
+  # .scripts/update.sh). coder_arch is derived from arch here because AWS spells
+  # it x86_64/arm64 while Coder uses amd64/arm64.
+  #
+  # Read instance-types.json with a fallback: Terraform resolves file() from the
+  # root module, but Coder's dynamic parameters preview resolves it from this
+  # module's directory, so neither path works on its own.
+  raw_instances = jsondecode(try(file("${path.module}/instance-types.json"), file("instance-types.json")))
+
+  instance_types = [
+    for instance in local.raw_instances : merge(instance, {
+      coder_arch = instance.arch == "arm64" ? "arm64" : "amd64"
+    })
+  ]
+
+  included_instances = [
+    for instance in local.instance_types : instance
+    if contains(var.include, split(".", instance.type)[0])
+  ]
+
+  spec_labels = {
+    for instance in local.included_instances : instance.type => format(
+      "%d vCPU, %g GiB RAM%s (%s)",
+      instance.vcpus,
+      instance.memory_mib / 1024,
+      instance.gpus > 0 ? format(", %d GPU", instance.gpus) : "",
+      instance.coder_arch
+    )
+  }
+
+  label_counts = {
+    for label in distinct(values(local.spec_labels)) : label =>
+    length([for l in values(local.spec_labels) : l if l == label])
+  }
+
+  # spec label, with the instance type appended when families share a label so
+  # option names stay unique (Coder requires that).
+  display_labels = {
+    for instance_type, spec_label in local.spec_labels : instance_type =>
+    local.label_counts[spec_label] > 1 ? "${trimsuffix(spec_label, ")")}, ${instance_type})" : spec_label
+  }
+
+  # Final picker entries in the catalog's memory-sorted order. name is the spec
+  # label unless custom_metadata overrides it; description is the instance type,
+  # shown as the option's tooltip.
+  options = [
+    for instance in local.included_instances : {
+      instance_type = instance.type
+      name          = coalesce(try(var.custom_metadata[instance.type].name, null), local.display_labels[instance.type])
+      description   = coalesce(try(var.custom_metadata[instance.type].description, null), instance.type)
+    }
+  ]
+}
+
+data "coder_parameter" "instance_type" {
+  count        = var.create_parameter ? 1 : 0
+  name         = "aws_ec2_instance_type"
+  display_name = var.display_name
+  description  = var.description
+  default      = var.default == "" ? null : var.default
+  order        = var.coder_parameter_order
+  mutable      = var.mutable
+  dynamic "option" {
+    # local.options maps each instance type to its picker name and description.
+    for_each = local.options
+    iterator = opt
+    content {
+      value       = opt.value.instance_type
+      name        = opt.value.name
+      description = opt.value.description
+    }
+  }
+}
+
+output "value" {
+  description = "The selected AWS EC2 instance type. Use it as the key into the instances output."
+  value       = var.create_parameter ? one(data.coder_parameter.instance_type[*].value) : var.default
+}
+
+output "instances" {
+  description = "All AWS EC2 instance types keyed by instance type ID, with raw specs (vcpus, memory_mib, gpus) and architecture (coder_arch, arch)."
+  value       = { for instance in local.instance_types : instance.type => instance }
+}
diff --git a/registry/coder/modules/aws-ec2-instance-type/main.tftest.hcl b/registry/coder/modules/aws-ec2-instance-type/main.tftest.hcl
new file mode 100644
index 000000000..01ca374a7
--- /dev/null
+++ b/registry/coder/modules/aws-ec2-instance-type/main.tftest.hcl
@@ -0,0 +1,190 @@
+run "parameter_name" {
+  command = plan
+
+  assert {
+    condition     = data.coder_parameter.instance_type[0].name == "aws_ec2_instance_type"
+    error_message = "Parameter name should be aws_ec2_instance_type"
+  }
+}
+
+run "custom_order" {
+  command = plan
+
+  variables {
+    coder_parameter_order = 99
+  }
+
+  assert {
+    condition     = data.coder_parameter.instance_type[0].order == 99
+    error_message = "coder_parameter_order should propagate to the parameter order"
+  }
+}
+
+run "default_output" {
+  command = apply
+
+  assert {
+    condition     = output.value == ""
+    error_message = "value should be empty when no default is set"
+  }
+}
+
+run "custom_default" {
+  command = apply
+
+  variables {
+    default = "t3.large"
+  }
+
+  assert {
+    condition     = output.value == "t3.large"
+    error_message = "value should match the configured default"
+  }
+}
+
+run "disabling_parameter_skips_creation" {
+  command = apply
+
+  variables {
+    create_parameter = false
+    default          = "t4g.large"
+  }
+
+  assert {
+    condition     = length(data.coder_parameter.instance_type) == 0
+    error_message = "No coder_parameter should be created when create_parameter is false"
+  }
+
+  assert {
+    condition     = output.value == "t4g.large"
+    error_message = "value should fall back to default when the parameter is disabled"
+  }
+}
+
+run "default_include_covers_template_types" {
+  command = apply
+
+  assert {
+    condition = alltrue([
+      for v in ["t3.micro", "t3.small", "t3.medium", "t3.large", "t3.xlarge", "t3.2xlarge"] :
+      contains([for o in data.coder_parameter.instance_type[0].option : o.value], v)
+    ])
+    error_message = "The default t3 family must include every instance type used by the AWS templates"
+  }
+}
+
+run "include_filters_by_family" {
+  command = apply
+
+  variables {
+    include = ["c5"]
+  }
+
+  assert {
+    condition     = contains([for o in data.coder_parameter.instance_type[0].option : o.value], "c5.large") && !contains([for o in data.coder_parameter.instance_type[0].option : o.value], "t3.micro")
+    error_message = "include should show the requested family and hide others"
+  }
+}
+
+run "include_allows_multiple_families" {
+  command = apply
+
+  variables {
+    include = ["t3", "c5"]
+  }
+
+  assert {
+    condition     = contains([for o in data.coder_parameter.instance_type[0].option : o.value], "t3.micro") && contains([for o in data.coder_parameter.instance_type[0].option : o.value], "c5.large") && !contains([for o in data.coder_parameter.instance_type[0].option : o.value], "m5.large")
+    error_message = "include should accept multiple families and exclude the rest"
+  }
+
+  assert {
+    condition     = length([for o in data.coder_parameter.instance_type[0].option : o if o.value == "c5.large" && o.name == "2 vCPU, 4 GiB RAM (amd64, c5.large)"]) == 1
+    error_message = "a spec label shared across families should be disambiguated with the instance type"
+  }
+
+  assert {
+    condition     = length([for o in data.coder_parameter.instance_type[0].option : o if o.value == "t3.large" && o.name == "2 vCPU, 8 GiB RAM (amd64)"]) == 1
+    error_message = "a unique spec label should stay specs-only"
+  }
+}
+
+run "empty_include_is_rejected" {
+  command = plan
+
+  variables {
+    include = []
+  }
+
+  expect_failures = [var.include]
+}
+
+run "option_name_is_specs_and_tooltip_is_instance_type" {
+  command = apply
+
+  assert {
+    condition     = length([for o in data.coder_parameter.instance_type[0].option : o if o.value == "t3.medium" && o.name == "2 vCPU, 4 GiB RAM (amd64)" && o.description == "t3.medium"]) == 1
+    error_message = "Option name should be the computed specs with arch and the description should be the instance type"
+  }
+}
+
+run "custom_metadata_overrides" {
+  command = apply
+
+  variables {
+    custom_metadata = {
+      "t3.medium" = {
+        name        = "Standard"
+        description = "custom"
+      }
+    }
+  }
+
+  assert {
+    condition     = length([for o in data.coder_parameter.instance_type[0].option : o if o.value == "t3.medium" && o.name == "Standard" && o.description == "custom"]) == 1
+    error_message = "custom_metadata should override the option name and description"
+  }
+}
+
+run "instances_output_exposes_specs_and_derived_fields" {
+  command = plan
+
+  assert {
+    condition     = length(output.instances) == length(local.instance_types)
+    error_message = "The instances output should expose every catalog entry keyed by value"
+  }
+
+  assert {
+    condition     = output.instances["t3.medium"].vcpus == 2 && output.instances["t3.medium"].memory_mib == 4096 && output.instances["t3.medium"].gpus == 0
+    error_message = "Raw specs should be exposed as numeric fields"
+  }
+
+  assert {
+    condition     = output.instances["t3.medium"].coder_arch == "amd64" && output.instances["t3.medium"].arch == "x86_64"
+    error_message = "x86 instances should derive amd64 from the x86_64 arch"
+  }
+
+  assert {
+    condition     = output.instances["m7g.large"].coder_arch == "arm64" && output.instances["m7g.large"].arch == "arm64"
+    error_message = "Graviton instances should derive arm64"
+  }
+
+  assert {
+    condition     = output.instances["g4dn.12xlarge"].gpus == 4
+    error_message = "gpus should reflect the source data"
+  }
+}
+
+run "value_is_key_in_instances" {
+  command = apply
+
+  variables {
+    include = ["t4g"]
+    default = "t4g.medium"
+  }
+
+  assert {
+    condition     = contains(keys(output.instances), output.value) && output.instances[output.value].coder_arch == "arm64"
+    error_message = "The selected value must be a key in the instances output"
+  }
+}