diff --git a/.env.example b/.env.example
index b94479e..7ec20e7 100644
--- a/.env.example
+++ b/.env.example
@@ -8,7 +8,8 @@ MAPLE_PORT=8080
 # Maple Backend Configuration
 # Production: https://enclave.trymaple.ai
 # Development: https://enclave.secretgpt.ai  
-# Local: http://localhost:3000
+# Local: use `just run-local`; plain HTTP mock attestation is compile-time
+# gated and is never enabled in release, Docker, or embedded Maple builds.
 MAPLE_BACKEND_URL=https://enclave.trymaple.ai
 
 # Authentication
diff --git a/CLAUDE.md b/CLAUDE.md
index 4ea10ad..4d9acb3 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -55,11 +55,40 @@ Maple Proxy is a lightweight OpenAI-compatible proxy server that forwards reques
    - Handles streaming responses for chat completions
    - Transforms responses to OpenAI format
 
+### TEE attestation boundary
+
+TEE measurement authorization is owned by the OpenSecret SDK. Maple Proxy
+should only call `perform_attestation_handshake`; do not add a proxy-specific
+PCR allowlist or Sigstore/Rekor verifier.
+
+The intended SDK handshake authenticates the AWS Nitro attestation document,
+compares the complete PCR0/PCR1/PCR2 tuple with a release snapshot embedded in
+the SDK, and only then accepts the enclave public key and performs key exchange.
+There is no runtime Sigstore/Rekor or release-metadata network lookup. At SDK
+update time, the updater verifies the release manifest and Cosign bundle,
+including the expected signing identity and Rekor evidence, before generating
+the embedded snapshot.
+
+Mock attestation is available only through the explicitly named
+`insecure-local-mock-attestation` Cargo feature. Keep it disabled in release,
+Docker, and embedded Maple builds; only `just run-local` opts in.
+
+Rekor supplies tamper-evident transparency-log evidence for the signed release
+statement used to generate that snapshot. It does not itself prove Nix
+reproducibility, release freshness, rollback prevention, or revocation.
+
+This integration branch pins an exact reviewed SDK commit with default features
+disabled. That staging commit deliberately contains an empty release snapshot,
+so remote handshakes fail closed. Before release, replace the pin with a
+snapshot-bearing reviewed commit or published crate; do not invent an
+unpublished version or vendor the SDK here.
+
 ### Request Flow
 
 1. Client sends OpenAI-compatible request to proxy
 2. Proxy extracts API key (from header or default config)
-3. Creates OpenSecret client and performs TEE attestation
+3. Creates an OpenSecret client and delegates TEE authentication, release
+   authorization, and key exchange to the SDK
 4. Forwards request to Maple backend (enclave.trymaple.ai or configured URL)
 5. Streams response back to client in OpenAI format
 
diff --git a/Cargo.lock b/Cargo.lock
index 4eddf78..97ff71c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1638,8 +1638,7 @@ checksum = "c08d65885ee38876c4f86fa503fb49d7b507c2b62552df7c70b2fce627e06381"
 [[package]]
 name = "opensecret"
 version = "3.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a7652ddb1661444ea0cbacacbc62c13f5073f1687a2e765e0195ebf29d3e394d"
+source = "git+https://github.com/OpenSecretCloud/OpenSecret-SDK?rev=1bd7196043b26b3a2f8080534bd14031afcd5cc8#1bd7196043b26b3a2f8080534bd14031afcd5cc8"
 dependencies = [
  "aes-gcm",
  "anyhow",
diff --git a/Cargo.toml b/Cargo.toml
index b282dcd..008d40a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,9 +27,15 @@ path = "src/lib.rs"
 name = "maple-proxy"
 path = "src/main.rs"
 
+[features]
+default = []
+# Explicit development-only opt-in. Release, Docker, and embedded Maple builds
+# use default features and cannot accept mock attestation documents.
+insecure-local-mock-attestation = ["opensecret/mock-attestation"]
+
 [dependencies]
 # OpenSecret SDK
-opensecret = "3.4.0"
+opensecret = { git = "https://github.com/OpenSecretCloud/OpenSecret-SDK", rev = "1bd7196043b26b3a2f8080534bd14031afcd5cc8", default-features = false }
 
 # Web server
 axum = { version = "0.8.4", features = ["http2", "macros"] }
diff --git a/README.md b/README.md
index 3042a1c..c802a48 100644
--- a/README.md
+++ b/README.md
@@ -7,7 +7,8 @@ Environment (TEE) processing.
 ## 🚀 Features
 
 - **OpenAI-Compatible Surface** - Models, chat completions, and embeddings endpoints
-- **Secure TEE Processing** - All requests processed in secure enclaves
+- **Attested TEE Transport** - The OpenSecret SDK establishes an attested,
+  encrypted channel before inference requests are forwarded
 - **Lossless Chat Parameters** - Provider-specific request fields pass through unchanged
 - **Streaming and Non-Streaming** - Supports both chat completion response modes
 - **Flexible Authentication** - Environment variables or per-request API keys
@@ -44,7 +45,7 @@ Set environment variables or use command-line arguments:
 # Environment Variables
 export MAPLE_HOST=127.0.0.1                    # Server host (default: 127.0.0.1)
 export MAPLE_PORT=8080                         # Server port (default: 8080)
-export MAPLE_BACKEND_URL=http://localhost:3000         # Maple backend URL (prod: https://enclave.trymaple.ai)
+export MAPLE_BACKEND_URL=https://enclave.trymaple.ai   # Maple backend URL
 export MAPLE_API_KEY=your-maple-api-key        # Default API key (optional)
 export MAPLE_DEBUG=true                        # Enable debug logging
 export MAPLE_ENABLE_CORS=true                  # Enable CORS
@@ -57,6 +58,10 @@ Or use CLI arguments:
 cargo run -- --host 0.0.0.0 --port 8080 --backend-url https://enclave.trymaple.ai
 ```
 
+For an unsigned local backend, use `just run-local`. That recipe alone enables
+the explicitly named `insecure-local-mock-attestation` Cargo feature. Generic,
+release, Docker, and embedded Maple builds leave the feature disabled.
+
 ## 🛠️ Usage
 
 ### Using as a Binary
@@ -453,9 +458,49 @@ cargo run
 ```
 
 1. **Client** makes standard OpenAI API calls to localhost
-2. **Maple Proxy** handles authentication and TEE handshake
-3. **Requests** are securely forwarded to Maple's TEE infrastructure
-4. **Responses** are streamed back to the client in OpenAI format
+2. **Maple Proxy** handles authentication and asks the OpenSecret SDK to
+   establish the TEE channel
+3. **OpenSecret SDK** authenticates and authorizes the enclave before accepting
+   its key and completing key exchange
+4. **Requests** are encrypted and forwarded to Maple's TEE infrastructure
+5. **Responses** are streamed back to the client in OpenAI format
+
+### TEE release authorization
+
+The Sigstore/Rekor release-authorization work belongs in the OpenSecret SDK,
+not in Maple Proxy. For each non-local backend, the SDK is expected to:
+
+1. verify the AWS Nitro attestation document, certificate chain, nonce, and
+   signature;
+2. extract and validate the complete PCR0/PCR1/PCR2 measurement tuple;
+3. compare that tuple with the release snapshot embedded in the SDK; and
+4. accept the enclave public key and perform key exchange only after the tuple
+   is present in that snapshot.
+
+Maple Proxy continues to call `perform_attestation_handshake`; it neither
+maintains a second PCR allowlist nor implements a separate Sigstore verifier.
+Keeping this policy in the SDK gives every Rust SDK consumer the same
+fail-closed authorization boundary before application data is sent.
+
+There is no Sigstore, Rekor, or other release-metadata network lookup during a
+runtime handshake. At SDK update time, the release-snapshot updater verifies
+the release manifest and Cosign bundle, including the expected signing identity
+and Rekor evidence, before generating the embedded snapshot. Consumers then
+review and pin the SDK release containing that generated snapshot.
+
+Sigstore makes a release statement and its signing identity tamper-evident in
+an append-only transparency log. It does **not** prove that an artifact was
+reproducibly built, and it does **not** make an old, previously authorized
+release fresh. Reproducibility remains a separate Nix rebuild/compare property;
+rollback prevention, revocation, or minimum-version policy must also be handled
+separately.
+
+> **Integration status:** this branch pins the exact reviewed SDK integration
+> commit with default features disabled. Its embedded release snapshot is
+> intentionally empty, so remote handshakes fail closed. Update the pin to a
+> reviewed snapshot-bearing commit or published crate after the first signed
+> backend release; do not merge or publish this staging state as a working
+> production proxy.
 
 ## 📝 License
 
diff --git a/justfile b/justfile
index 04251b8..b3e8888 100644
--- a/justfile
+++ b/justfile
@@ -61,7 +61,8 @@ run-with-backend url:
 
 # Run pointing to local backend
 run-local:
-    @just run-with-backend "http://localhost:3000"
+    @echo "🚧 Starting with development-only mock attestation enabled"
+    @bash -c 'set -a; source .env 2>/dev/null; set +a; MAPLE_BACKEND_URL=http://localhost:3000 cargo run --features insecure-local-mock-attestation'
 
 # Run pointing to production backend
 run-prod: