chore: remove the opaque provider value and use vendor-neutral examples

.github/ISSUE_TEMPLATE/bug_report.md

@@ -25,7 +25,7 @@ assignees: ''
 
 - OS:
 - Python version:
-- TEE provider (`auto` / `tpm` / `sev-snp` / `tdx` / `opaque` / `software-only`):
+- TEE provider (`auto` / `tpm` / `sev-snp` / `tdx` / `software-only`):
 
 ## Security impact
 

CHANGELOG.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Removed
+
+- The `opaque` attestation provider value. It had no collector and was never
+  selectable at runtime; a config naming `provider: opaque` now fails at load
+  with `unknown attestation provider`, like any other unknown provider. Docs,
+  example configs and the issue template no longer list it.
+
 ## [0.4.0] - 2026-09-30
 
 ### Security

SECURITY.md

@@ -21,7 +21,7 @@ The following components are in scope:
 
 - **Delegation chain**: scope attenuation correctness (a child grant must be a provable subset of its parent), signature verification, depth limits, and cross-chain replay protection
 - **Sealed peer channel**: any path by which a task payload could be read outside the peer's attested measurement
-- **TEE attestation path**: peer measurement verification for TPM 2.0, AMD SEV-SNP, Intel TDX, and OPAQUE Managed Runtime providers, and binding of the channel key to that measurement
+- **TEE attestation path**: peer measurement verification for TPM 2.0, AMD SEV-SNP, and Intel TDX providers, and binding of the channel key to that measurement
 - **Signing key handling**: hardware-sealed key generation, storage, and use
 - **Provenance record**: integrity of the delegation DAG; any path by which a valid TRACE record could be forged, reparented, or suppressed
 

docs/configuration.md

@@ -14,7 +14,7 @@ the reference HTTP transport.
 
 ```yaml
 attestation:
-  provider: auto            # auto | tpm | sev-snp | tdx | opaque | software-only
+  provider: auto            # auto | tpm | sev-snp | tdx | software-only
   enforcement_mode: enforcing  # enforcing | advisory | silent
   require_caller_attestation: none   # none | any | hardware
   # caller_verifier:                 # required for `hardware`, optional for `any`
@@ -46,7 +46,7 @@ proof).
 
 | Field | Default | Description |
 |---|---|---|
-| `attestation.provider` | `auto` | TEE provider for peer attestation. `auto` selects a detected hardware provider and fails if there is none; it never falls back to `software-only`, which has to be named explicitly. `opaque` is not implemented. |
+| `attestation.provider` | `auto` | TEE provider for peer attestation. `auto` selects a detected hardware provider and fails if there is none; it never falls back to `software-only`, which has to be named explicitly. Any other value is rejected as an unknown provider. |
 | `attestation.enforcement_mode` | `enforcing` | Intended mode. The peer path always fails closed on cA2A denials today; advisory and silent are accepted in config but not applied on the wire. |
 | `attestation.require_caller_attestation` | `none` | What the callee demands of a caller's own attestation, per [mutual-attestation.md](spec/mutual-attestation.md). `none` records the outcome and demands nothing; `any` requires an offer that appraises, software assurance included; `hardware` requires hardware assurance. At every rung an offer that is present and does not appraise is refused. |
 | `attestation.caller_verifier` | none | How to appraise a hardware report a caller offers. `platform` plus `trusted_roots_path` (a PEM bundle, resolved relative to the config file). Required when the rung is `hardware`; without it, a hardware offer at `none` or `any` is refused as unappraisable rather than accepted. Only `tpm` can be built today, via `ca2a_verify.tpm.tpm_verifier`. `sev-snp` and `tdx` are accepted by the vocabulary and refused at startup with the reason: their verifiers take raw evidence and a certificate chain, and no report-level wrapper exists yet. |

docs/hardware-validation.md

@@ -202,7 +202,7 @@ Trusted Launch VMs actually present, not a discrete TPM chip.
 
 ## Collection on real silicon: SEV-SNP and TDX, GCP, 2026-08-24
 
-Both collectors were run on genuine confidential VMs in GCP `opaque-dev`,
+Both collectors were run on genuine confidential VMs in a GCP project in
 `us-central1-a`, and the evidence each produced was appraised by this codebase's
 own verifiers to the vendor roots. The VMs were ephemeral and deleted after the
 capture.

docs/spec/attestation.md

@@ -63,7 +63,6 @@ All four are absent on `software-only`, which has no evidence by construction. A
 | `sev-snp` | AMD SEV-SNP | Verifier and collector both implemented (see below). `attest` produces a real report on a non-paravisor SNP guest through configfs-TSM. |
 | `tdx` | Intel TDX | Verifier and collector both implemented (see below). `attest` produces a real DCAP quote on a TDX guest through configfs-TSM. |
 | `tpm` | TPM 2.0 / vTPM | Verifier and collector both implemented (see below). `attest` produces a real quote on a Linux host with a TPM and tpm2-pytss. |
-| `opaque` | OPAQUE Confidential Runtime | Tier 3, explicit opt-in, not auto-selected |
 
 ## SEV-SNP verification
 

docs/spec/component-model.md

@@ -14,7 +14,7 @@ cA2A composes delegation verification, local policy, caller authentication, atte
 | Inbound handler | `ca2a_runtime.peer` | Verify, authenticate, appraise, authorize, and open the payload |
 | Channel | `ca2a_runtime.channel` | X25519 key agreement and authenticated encryption; reject wrong keys and altered ciphertext |
 | Attestation | `ca2a_runtime.attestation` | Challenge-bound channel offers and peer appraisal |
-| Providers | `ca2a_runtime.tee` | Software evidence or hardware collection for TPM, SEV-SNP, and TDX; OPAQUE has no collector |
+| Providers | `ca2a_runtime.tee` | Software evidence or hardware collection for TPM, SEV-SNP, and TDX |
 | Provenance | `ca2a_runtime.provenance` | Hash-linked decision records and consistency checks |
 | TRACE binding | `ca2a_runtime.trace_binding` | Signed TRACE records carrying delegation links |
 | Offline verification | `ca2a_verify.verify`, `ca2a_verify.dag` | Verify credentials and signed TRACE record paths against caller-supplied trust anchors |

examples/cross-operator-delegation/ca2a-config.yaml

@@ -5,7 +5,7 @@
 # validates with `ca2a validate-config`. See README.md for what is real vs
 # software-asserted in this example.
 attestation:
-  provider: software-only     # auto | tpm | sev-snp | tdx | opaque | software-only
+  provider: software-only     # auto | tpm | sev-snp | tdx | software-only
   enforcement_mode: advisory  # enforcing | advisory | silent
 
 max_delegation_depth: 8

examples/minimal/ca2a-config.yaml

@@ -1,5 +1,5 @@
 attestation:
-  provider: software-only   # auto | tpm | sev-snp | tdx | opaque | software-only
+  provider: software-only   # auto | tpm | sev-snp | tdx | software-only
   enforcement_mode: enforcing  # the peer path always fails closed today
   require_caller_attestation: none   # none | any | hardware; see docs/configuration.md
   # caller_verifier:                 # needed for `hardware`; TPM roots only today

examples/trace-dag/demo.py

@@ -73,8 +73,8 @@ def main() -> None:
             subject=SUBJECTS[i],
             signing_key=keys[i],
             context=HopContext.software(
-                model_provider="anthropic",
-                model_id="claude-opus-4-8",
+                model_provider="example-provider",
+                model_id="example-model",
                 image_label=f"ca2a-peer:{SUBJECTS[i].rsplit('/', 1)[-1]}",
                 policy_bundle_hash=digest(b"demo-policy-bundle"),
             ),

src/ca2a_runtime/config.py

@@ -16,7 +16,7 @@
 from ca2a_runtime.errors import ConfigError
 from ca2a_runtime.peer import REQUIRE_HARDWARE, REQUIRE_NONE, REQUIREMENT_VALUES
 
-VALID_PROVIDERS = frozenset({"auto", "tpm", "sev-snp", "tdx", "opaque", "software-only"})
+VALID_PROVIDERS = frozenset({"auto", "tpm", "sev-snp", "tdx", "software-only"})
 VALID_ENFORCEMENT = frozenset({"enforcing", "advisory", "silent"})
 
 # Platforms a config can name under ``attestation.caller_verifier.platform``. This

src/ca2a_runtime/policy.py

@@ -5,9 +5,9 @@
 intersected with this allow set, so a peer can never exercise more than both
 its grant and the callee's local policy permit.
 
-The intersection semantics here are policy-language-agnostic. Binding a full
-Cedar policy engine (as cMCP does) is tracked separately; this allow-set model
-is the enforcement primitive the peer path uses today.
+The intersection semantics here are policy-language-agnostic. ``LocalPolicy``
+below is the allow-set model; ``ca2a_runtime.cedar.CedarPolicy`` evaluates a
+Cedar policy bundle behind the same ``Policy`` protocol.
 """
 
 from __future__ import annotations

tests/unit/test_bootstrap.py

@@ -90,7 +90,12 @@ def test_auto_selects_a_detected_hardware_provider(monkeypatch: pytest.MonkeyPat
 
 def test_unimplemented_provider_rejected() -> None:
     with pytest.raises(ConfigError, match="not implemented"):
-        select_provider(Ca2aConfig(provider="opaque"))
+        select_provider(Ca2aConfig(provider="example-unknown"))
+
+
+def test_opaque_provider_rejected_as_unknown() -> None:
+    with pytest.raises(ConfigError, match="unknown attestation provider"):
+        Ca2aConfig.from_dict({"attestation": {"provider": "opaque"}})
 
 
 def test_no_caller_verifier_unless_configured() -> None:

tests/unit/test_trace_binding.py

@@ -41,8 +41,8 @@
 
 def _software_context(label: str = "ca2a-peer") -> HopContext:
     return HopContext.software(
-        model_provider="anthropic",
-        model_id="claude-opus-4-8",
+        model_provider="example-provider",
+        model_id="example-model",
         image_label=label,
         policy_bundle_hash=digest(b"policy-bundle"),
     )