diff --git a/implementations/gdi/README.md b/implementations/gdi/README.md
new file mode 100644
index 0000000..35a3fed
--- /dev/null
+++ b/implementations/gdi/README.md
@@ -0,0 +1,59 @@
+# GDI Driver
+
+**Governed Decision Intelligence** conformance driver for
+[`draft-farley-acta-signed-receipts`](https://datatracker.ietf.org/doc/draft-farley-acta-signed-receipts/).
+
+- **License:** Apache-2.0
+- **Spec:** https://github.com/mj3b/governed-decision-intelligence
+- **Contact:** @mj3b
+
+## What this driver adds
+
+Standard conformance drivers emit receipts that capture the policy outcome
+(allow/deny), the policy identifier, and chain integrity fields. This driver
+embeds a **Governed Decision Record (GDR)** in the receipt's `gdr` field,
+sealing the pre-decision reasoning state before the tool fires.
+
+The `result_hash` field is `sha256(JCS(GDR))`, binding:
+
+- `confidence_score` — numeric score against institutional thresholds
+- `gate_classification` — `routine | elevated_review | mandatory_escalation | blocked | deferred`
+- `reasoning_reconstruction` — plain-language explanation of the decision
+- `evidence_sources` — completeness classification per input source
+- `accountability_chain` — named roles and responsibilities
+
+Receipt integrity (attribution, ordering, tamper detection) is independent
+of payload semantics per the v1.1 spec. An auditor verifies the receipt
+offline with `@veritasacta/verify`, then reads GDR fields from the now-attested
+payload to assess decision quality.
+
+## Bilateral pattern
+
+For threat models requiring pre-execution intent binding, this driver supports
+the bilateral pattern described in the v1.1 spec discussion
+([VeritasActa/verify#1](https://github.com/VeritasActa/verify/issues/1)):
+
+- Receipt 1: sealed over the pre-execution GDR (intent)
+- Receipt 2: sealed over the post-execution result, chained via `previous_receipt_hash`
+
+This binds both sides independently. The current driver emits single receipts
+for v1.0 conformance; bilateral emission is in progress.
+
+## Requirements
+
+- Python 3.10+
+- `pip install cryptography`
+
+## Running
+
+```bash
+cd implementations/gdi
+chmod +x run.sh
+./run.sh
+```
+
+Receipts are written to `receipts/gdi/`. Run the conformance verifier:
+
+```bash
+./conformance/verify.sh receipts/gdi/
+```
diff --git a/implementations/gdi/gdi_driver.py b/implementations/gdi/gdi_driver.py
new file mode 100644
index 0000000..d7cee00
--- /dev/null
+++ b/implementations/gdi/gdi_driver.py
@@ -0,0 +1,171 @@
+#!/usr/bin/env python3
+"""
+GDI (Governed Decision Intelligence) driver for agent-governance-testvectors.
+
+Produces v2 structured-envelope receipts with a GDR payload embedded in
+`payload.gdr`. The GDR captures pre-decision reasoning state: confidence
+score, gate classification, evidence completeness, and accountability chain.
+
+Wire format: v2 envelope conforming to draft-farley-acta-signed-receipts.
+Verified by @veritasacta/verify.
+
+Apache-2.0. https://github.com/mj3b/governed-decision-intelligence
+"""
+
+from __future__ import annotations
+import base64, hashlib, json, sys, time
+from pathlib import Path
+from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
+
+# Conformance keypair -- testing only
+SEED = bytes.fromhex("0000000000000000000000000000000000000000000000000000000000000001")
+_PRIV = Ed25519PrivateKey.from_private_bytes(SEED)
+_PUB  = _PRIV.public_key().public_bytes_raw()
+PUBKEY_HEX = _PUB.hex()
+_KID = base64.urlsafe_b64encode(hashlib.sha256(_PUB).digest()[:16]).rstrip(b"=").decode()
+
+
+def evaluate_cedar(tool_name: str, context: dict) -> str:
+    destructive = {"rm -rf", "dd", "mkfs", "shred"}
+    safe_bash   = {"git", "npm", "ls", "cat", "pwd", "echo", "node", "python"}
+    if tool_name == "Bash":
+        cmd = context.get("command_pattern", "")
+        if cmd in destructive: return "deny"
+        if cmd in safe_bash:   return "allow"
+        return "deny"
+    if tool_name in {"Read", "Glob", "Grep", "WebSearch"}: return "allow"
+    if tool_name in {"Write", "Edit"}:
+        return "allow" if context.get("path_starts_with") == "./" else "deny"
+    return "deny"
+
+
+GATE_MAP = {
+    ("allow","Read"):      ("routine",              0.92),
+    ("allow","Glob"):      ("routine",              0.90),
+    ("allow","Grep"):      ("routine",              0.90),
+    ("allow","WebSearch"): ("routine",              0.88),
+    ("allow","Bash"):      ("elevated_review",      0.78),
+    ("allow","Write"):     ("elevated_review",      0.75),
+    ("allow","Edit"):      ("elevated_review",      0.75),
+    ("deny", "Bash"):      ("blocked",              0.15),
+    ("deny", "Write"):     ("mandatory_escalation", 0.22),
+    ("deny", "Edit"):      ("mandatory_escalation", 0.22),
+}
+
+def build_gdr(tool_name, tool_input, context, decision, policy_id,
+              session_id, sequence, timestamp):
+    gate_class, confidence = GATE_MAP.get((decision, tool_name), ("deferred", 0.50))
+    evidence_sources = []
+    if tool_input:
+        evidence_sources.append({"completeness":"complete",
+            "fields_present":sorted(tool_input.keys()), "source":"tool_input"})
+    if context:
+        evidence_sources.append({"completeness":"complete",
+            "fields_present":sorted(context.keys()), "source":"context"})
+    reasoning = (
+        f"{tool_name} evaluated against {policy_id}. Gate: {gate_class}. "
+        + (f"Confidence {confidence:.2f} meets threshold. Action approved."
+           if decision == "allow"
+           else f"Confidence {confidence:.2f} below threshold or forbid matched. Action blocked.")
+    )
+    return {
+        "accountability_chain": [
+            {"identity": f"session:{session_id}", "responsibility": "policy_evaluation", "role": "agent_runtime"},
+            {"identity": "human:operator",        "responsibility": "threshold_approval",  "role": "governance_owner"},
+        ],
+        "confidence_score":         confidence,
+        "decision":                 decision,
+        "evidence_sources":         evidence_sources,
+        "gate_classification":      gate_class,
+        "gdr_timestamp":            timestamp,
+        "gdr_version":              "2.0",
+        "policy_id":                policy_id,
+        "reasoning_reconstruction": reasoning,
+        "sequence":                 sequence,
+        "session_id":               session_id,
+        "tool_input":               tool_input,
+        "tool_name":                tool_name,
+    }
+
+def jcs(obj) -> bytes:
+    return json.dumps(obj, sort_keys=True, separators=(",",":"), ensure_ascii=False).encode()
+
+def sha256p(data) -> str:
+    return "sha256:" + hashlib.sha256(data).hexdigest()
+
+
+def build_receipt(fixture: dict, sequence: int, prev_canonical: bytes | None):
+    tool_name  = fixture["tool_name"]
+    tool_input = fixture.get("tool_input", {})
+    context    = fixture.get("context", {})
+    session_id = fixture.get("session_id", "testvectors-session-001")
+    policy_id  = "autoresearch-safe"
+    decision   = evaluate_cedar(tool_name, context)
+    timestamp  = time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime())
+
+    gdr = build_gdr(tool_name, tool_input, context, decision, policy_id,
+                    session_id, sequence, timestamp)
+
+    parent_receipt_hash = sha256p(prev_canonical) if prev_canonical else None
+
+    # Assemble complete receipt (all fields) BEFORE signing
+    # The verifier hashes the full object minus the signature field
+    receipt = {
+        "algorithm":           "ed25519",
+        "issued_at":           timestamp,
+        "issuer":              "gdi:governed-decision-intelligence",
+        "kid":                 _KID,
+        "parent_receipt_hash": parent_receipt_hash,
+        "payload": {
+            "action":        {"kind": tool_name, "target": session_id},
+            "decision":      decision,
+            "gdr":           gdr,
+            "params_hash":   sha256p(jcs(tool_input)) if tool_input else None,
+            "policy_digest": sha256p(jcs({"id": policy_id})),
+            "policy_id":     policy_id,
+            "prev_hash":     parent_receipt_hash,
+            "reason_code":   "policy_match" if decision == "allow" else "policy_deny",
+            "sequence":      sequence,
+            "session_id":    session_id,
+            "tier":          "evidenced",
+            "timestamp":     timestamp,
+            "tool":          tool_name,
+            "type":          "scopeblind.receipt.v2",
+        },
+        "pubkey":   PUBKEY_HEX,
+        "sequence": sequence,
+        "type":     "decision_receipt",
+        "v":        2,
+    }
+
+    # Sign JCS of receipt without the signature field
+    canonical_bytes = jcs(receipt)
+    receipt["signature"] = _PRIV.sign(canonical_bytes).hex()
+
+    return receipt, canonical_bytes
+
+
+def main():
+    repo_root    = Path(__file__).resolve().parents[2]
+    fixtures_dir = repo_root / "fixtures" / "inputs"
+    if not fixtures_dir.exists():
+        print(f"No fixture files found in {fixtures_dir}", file=sys.stderr)
+        sys.exit(1)
+
+    out_dir = repo_root / "receipts" / "gdi"
+    out_dir.mkdir(parents=True, exist_ok=True)
+
+    prev_canonical = None
+    count = 0
+    for f in sorted(fixtures_dir.glob("*.json")):
+        fixture  = json.loads(f.read_text())
+        sequence = fixture.get("sequence", count + 1)
+        receipt, canonical = build_receipt(fixture, sequence, prev_canonical)
+        (out_dir / f.name).write_text(json.dumps(receipt, indent=2))
+        prev_canonical = canonical
+        count += 1
+
+    print(f"gdi: {count} receipts in {out_dir}")
+
+if __name__ == "__main__":
+    main()
diff --git a/implementations/gdi/key.hex b/implementations/gdi/key.hex
new file mode 100644
index 0000000..0ef0526
--- /dev/null
+++ b/implementations/gdi/key.hex
@@ -0,0 +1 @@
+4cb5abf6ad79fbf5abbccafcc269d85cd2651ed4b885b5869f241aedf0a5ba29
diff --git a/implementations/gdi/run.sh b/implementations/gdi/run.sh
new file mode 100644
index 0000000..28683c2
--- /dev/null
+++ b/implementations/gdi/run.sh
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+# GDI (Governed Decision Intelligence) conformance driver.
+#
+# Reads fixtures from ../../fixtures/inputs/
+# Writes v2 envelope receipts (with embedded GDR payload) to ../../receipts/gdi/
+#
+# Signature verification requires --key because GDI uses the shared fixture
+# keypair directly rather than a hosted JWKS endpoint. Pass the fixture
+# public key to @veritasacta/verify:
+#
+#   npx @veritasacta/verify ../../receipts/gdi/*.json \
+#     --key 4cb5abf6ad79fbf5abbccafcc269d85cd2651ed4b885b5869f241aedf0a5ba29
+#
+# Apache-2.0. https://github.com/mj3b/governed-decision-intelligence
+
+set -uo pipefail
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+command -v python3 >/dev/null 2>&1 || { echo "skip: python3 not found"; exit 77; }
+python3 -c "from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey" \
+    2>/dev/null || { echo "skip: pip install cryptography"; exit 77; }
+
+python3 "$SCRIPT_DIR/gdi_driver.py"