diff --git a/.gitignore b/.gitignore
index 23b879b..f053016 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,4 +9,7 @@ audit.json
 .DS_Store
 runner-data/
 .env.secrets
-terraform/bootstrap/.bootstrap_state.json
\ No newline at end of file
+terraform/bootstrap/.bootstrap_state.json
+terraform/spike/.terraform/
+terraform/spike/tfplan
+terraform/spike/*.tfstate*
\ No newline at end of file
diff --git a/adapters/terraform/adapter.py b/adapters/terraform/adapter.py
new file mode 100644
index 0000000..bf0a591
--- /dev/null
+++ b/adapters/terraform/adapter.py
@@ -0,0 +1,131 @@
+"""ACDL Terraform adapter — compile a Target Stack IR instance to Terraform.
+
+ARCHITECTURE.md §12.2: the adapter translates the IR-typed L1 interface
+to a Terraform variable/output block, the L2 thin-composition tree to a
+root module that calls the L1 modules, the IR-typed relationships to
+Terraform module references, and emits a Terraform plan from the IR.
+
+The adapter is a THIN LAYER; it does not own L1/L2 content — it only
+translates. Substrate-agnostic in, Terraform out.
+
+Spike scope (Phase 09): handles one L1 (l1-s3, IR type aws:s3:bucket).
+L2 thin-composition + relationships land in Phase 10.
+
+CLI: adapter.py <ir_instance.json> <out_dir>
+"""
+
+import json
+import os
+import sys
+
+
+# IR type -> Terraform resource type. The only substrate-specific table.
+# As more L1s land, this grows; the L1 content + IR do not change.
+TYPE_MAP = {
+    "aws:s3:bucket": "aws_s3_bucket",
+}
+
+
+def _tf_block(block_type, name, body_lines, indent=2):
+    head = f'{block_type} "{name}" {{'
+    body = "\n".join(f"  {l}" for l in body_lines)
+    return f"{head}\n{body}\n}}\n"
+
+
+def _emit_resource(resource):
+    rtype = resource["type"]
+    rid = resource["id"]
+    tf_type = TYPE_MAP.get(rtype)
+    if not tf_type:
+        raise ValueError(f"unknown IR type {rtype!r} (adapter spike handles aws:s3:bucket only)")
+    body = []
+    inputs = resource.get("inputs", {})
+    # S3 bucket: bucket_name -> bucket arg; region -> provider (handled separately)
+    if "bucket_name" in inputs:
+        body.append(f'bucket = "{inputs["bucket_name"]}"')
+    # NFR: versioning (default true)
+    nfrs = resource.get("nfrs", {})
+    versioning = nfrs.get("versioning", True) if isinstance(nfrs, dict) else True
+    body.append("versioning {")
+    body.append(f'  enabled = {"true" if versioning else "false"}')
+    body.append("}")
+    return _tf_block("resource", f'aws_s3_bucket.{rid}', body) if False else _resource_block(rid, tf_type, body)
+
+
+def _resource_block(rid, tf_type, body):
+    """Emit a top-level resource block."""
+    head = f'resource "{tf_type}" "{rid}" {{'
+    body_str = "\n".join(f"  {l}" for l in body)
+    return f"{head}\n{body_str}\n}}\n"
+
+
+def _emit_output(output_name, value_expr):
+    return f'output "{output_name}" {{\n  value = {value_expr}\n}}\n'
+
+
+def adapt(ir_instance, out_dir):
+    """Emit main.tf + terraform.tf + providers.tf to out_dir for the IR instance."""
+    os.makedirs(out_dir, exist_ok=True)
+    stack = ir_instance["stack"]
+    resources = ir_instance["resources"]
+
+    # --- providers.tf: aws provider, region from the first resource's inputs.region ---
+    region = "us-east-1"
+    for r in resources:
+        if "region" in r.get("inputs", {}):
+            region = r["inputs"]["region"]
+            break
+    providers_tf = (
+        f'provider "aws" {{\n'
+        f'  region = "{region}"\n'
+        f'}}\n'
+    )
+
+    # --- terraform.tf: required_version + required_providers + S3 backend (no DynamoDB lock per D-P09-1) ---
+    terraform_tf = (
+        'terraform {\n'
+        '  required_version = ">= 1.9, < 1.10"\n'
+        '  required_providers {\n'
+        '    aws = {\n'
+        '      source  = "hashicorp/aws"\n'
+        '      version = "~> 5.0"\n'
+        '    }\n'
+        '  }\n'
+        '  backend "s3" {\n'
+        '    bucket = "acdl-tfstate-581513795199-us-east-1"\n'
+        '    key    = "spike/l1-s3/terraform.tfstate"\n'
+        '    region = "us-east-1"\n'
+        '  }\n'
+        '}\n'
+    )
+
+    # --- main.tf: resources + outputs ---
+    main_tf_parts = []
+    for r in resources:
+        main_tf_parts.append(_emit_resource(r))
+        rid = r["id"]
+        outputs = r.get("outputs", {})
+        for out_name in outputs:
+            if out_name == "bucket_arn":
+                main_tf_parts.append(_emit_output("bucket_arn", f"aws_s3_bucket.{rid}.arn"))
+            elif out_name == "bucket_name":
+                main_tf_parts.append(_emit_output("bucket_name", f"aws_s3_bucket.{rid}.id"))
+    main_tf = "\n".join(main_tf_parts)
+
+    with open(os.path.join(out_dir, "main.tf"), "w") as fh:
+        fh.write(main_tf)
+    with open(os.path.join(out_dir, "terraform.tf"), "w") as fh:
+        fh.write(terraform_tf)
+    with open(os.path.join(out_dir, "providers.tf"), "w") as fh:
+        fh.write(providers_tf)
+    return out_dir
+
+
+if __name__ == "__main__":
+    if len(sys.argv) != 3:
+        print("usage: adapter.py <ir_instance.json> <out_dir>", file=sys.stderr)
+        sys.exit(2)
+    with open(sys.argv[1], "r") as fh:
+        ir = json.load(fh)
+    adapt(ir, sys.argv[2])
+    print(f"adapter: emitted terraform to {sys.argv[2]}", file=sys.stderr)
\ No newline at end of file
diff --git a/scripts/run_spike_plan.sh b/scripts/run_spike_plan.sh
new file mode 100755
index 0000000..7fc38a5
--- /dev/null
+++ b/scripts/run_spike_plan.sh
@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+# scripts/run_spike_plan.sh - run the v1.1 spike's real terraform plan against AWS.
+#
+# Uses the rotated spike key (D-039) from gitignored .env.secrets.
+# Plan-only (no apply); -lock=false per D-P09-1 (the spike's DynamoDB
+# outbox table PK is contractId, not Terraform's expected LockID; plan
+# does not write state so locking is unnecessary; v1.2 creates a proper
+# LockID-keyed acdl-tflock table).
+set -u
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$ROOT"
+
+ENV_FILE="$ROOT/.env.secrets"
+[ -f "$ENV_FILE" ] || { echo "FAIL: .env.secrets missing (run scripts/rotate_spike_key.sh)" >&2; exit 1; }
+set -a
+. "$ENV_FILE"
+set +a
+export AWS_ACCESS_KEY_ID="$ACDL_AWS_ACCESS_KEY_ID"
+export AWS_SECRET_ACCESS_KEY="$ACDL_AWS_SECRET_ACCESS_KEY"
+export AWS_DEFAULT_REGION="$AWS_DEFAULT_REGION"
+
+cd terraform/spike
+echo "=== terraform init -lock=false -input=false ==="
+terraform init -lock=false -input=false
+echo "=== terraform validate ==="
+terraform validate
+echo "=== terraform plan -lock=false -input=false -out=tfplan ==="
+terraform plan -lock=false -input=false -out=tfplan
+echo "spike plan OK"
\ No newline at end of file
diff --git a/terraform/spike/main.tf b/terraform/spike/main.tf
new file mode 100644
index 0000000..d750400
--- /dev/null
+++ b/terraform/spike/main.tf
@@ -0,0 +1,14 @@
+resource "aws_s3_bucket" "s3" {
+  bucket = "acdl-spike-bucket"
+  versioning {
+    enabled = true
+  }
+}
+
+output "bucket_arn" {
+  value = aws_s3_bucket.s3.arn
+}
+
+output "bucket_name" {
+  value = aws_s3_bucket.s3.id
+}
diff --git a/terraform/spike/providers.tf b/terraform/spike/providers.tf
new file mode 100644
index 0000000..c125940
--- /dev/null
+++ b/terraform/spike/providers.tf
@@ -0,0 +1,3 @@
+provider "aws" {
+  region = "us-east-1"
+}
diff --git a/terraform/spike/terraform.tf b/terraform/spike/terraform.tf
new file mode 100644
index 0000000..c1d14ab
--- /dev/null
+++ b/terraform/spike/terraform.tf
@@ -0,0 +1,14 @@
+terraform {
+  required_version = ">= 1.9, < 1.10"
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = "~> 5.0"
+    }
+  }
+  backend "s3" {
+    bucket = "acdl-tfstate-581513795199-us-east-1"
+    key    = "spike/l1-s3/terraform.tfstate"
+    region = "us-east-1"
+  }
+}