NK-WP-0056-T19 done: approval exercise receipt (16 checks against KeyCape 9e082dca, approval-engine f41a9ca)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 523928@bnt-lap001
Assistant-Session: 6c737afb-9c14-4152-9f02-477214b9c350

docs/evidence/2026-11-03-nk56-t19-approval-exercise/README.md

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+# NK-WP-0056-T19: executor approval exercise against the real services (2026-11-03)
+
+Agent-run, local only, synthetic keys, everything removed afterwards:
+`python3 bounded-executor/exercise_approval_identity.py --receipt FILE`. It follows secrets-engine's
+`tools/exercise_approval_identity.py`.
+
+**Setup:**
+
+- **KeyCape:** a disposable container on the pinned image `9e082dca` (`sso-mfa/k8s/keycape/deployment.yaml`). It is
+  configured with two clients:
+  - the `client-from-case` output for case `nk-bind-executor-approval`;
+  - key-cape's example `approval-engine-operator`, which acts as the revoker and as a service that tries to approve.
+- **approval-engine:** source `f41a9ca`, in-process, with its `JWTAuthenticator` against KeyCape's JWKS.
+- **Executor:** the real code. That covers `cli.run_request`, `KeyCapeClientCredentials`, `ApprovalEngine`, and
+  `executor.Run.preflight` and `consume`. Only the OpenBao lane is replaced: the generated client secret is handed to
+  the client directly. The T18 tests cover that lane.
+
+Receipt: [`receipt.json`](receipt.json). It is value-free; the harness asserts that no generated secret appears in it.
+It records the image, the source commits, the executed files' hashes and the case hash. The commits are
+`issuer_contract_commit` (key-cape), approval-engine, and net-kingdom `e1ef4bf` (executor code from `625ad65`).
+
+| Check | Result |
+| --- | --- |
+| The request phase creates the approval as `service:nk-bind-executor` through a verified KeyCape JWT | passed |
+| Create with another actor | 403 |
+| Preflight before approval | refused, `approval_status` |
+| A service (`approval-engine-operator`) approves a human-control approval | 403, no entry |
+| A human aal2 entry approves | `approved` |
+| The executor's preflight accepts KeyCape's aal2 entry | passed (after the fix below) |
+| Consume | `consumed`; the read-back shows the admission digest and this run's id |
+| Retry with the same digest | idempotent |
+| A second run on the consumed approval | refused before consume |
+| A different digest | 409; the consumption is unchanged |
+| A changed admission | refused, `approval_binding` |
+| Revoke before consume | refused by the executor and by approval-engine (409). The executor's own token cannot revoke (403) |
+| A human aal1 entry | accepted by approval-engine (no floor declared), refused by the executor (`approval_entry`) |
+| The executor client asks for `approval:approve` | KeyCape refuses with `invalid_profile_usage` |
+| A token for another scope | 403 on create and on consume |
+| A wrong client secret | refused at the token endpoint |
+
+**Limitations:**
+
+- approval-engine runs from source, not from the deployed image.
+- The founder's entry is seeded through approval-engine's store. It uses the exact assurance object KeyCape mints and
+  the API persists, but there is no human PKCE login.
+- There is no informed-decision presentation; the T21 tests cover it.
+- Plain HTTP on loopback.
+
+## Finding that changed the executor
+
+**Every real founder approval would have been refused.** approval-engine stores an entry's `assurance` as the
+verified token's claim, serialized as JSON: `{"at", "level", "methods", "mfa", "source"}`. KeyCape mints that object
+in `token.go` `assuranceClaim`, and approval-engine stores it in `api.py`. The executor compared it with the bare
+string `"aal2"`, which the fakes supplied. Against the real store, preflight refused with `approval_entry`.
+
+The fix (`625ad65`): `executor.entry_is_aal2` parses the object and requires level `aal2` or `aal3` with `mfa: true`.
+Anything else fails closed, including a bare `"aal2"`. The fakes use the real shape, and a unit test covers the
+refusals.
+
+## Consequences
+
+- **The pinned executor image needs rebuilding.** The image pinned in the rapp by T18 (`c67cb044`, `b90951a`) has the
+  defect. It must be rebuilt from `625ad65` or later and re-pinned before T06.
+- **Open for the founder.** approval-engine accepts an aal1 human entry unless the approval declares
+  `required_assurance` (APPROVAL-WP-0007-T01). Today the executor is the only aal2 guard. The request phase could
+  declare `required_assurance: {"level": "aal2"}` so approval-engine also enforces the floor at approve and consume
+  time. That needs the deployed approval-engine to be at schema v7 or later, and a check that informed-decision's
+  present_existing accepts the field.

docs/evidence/2026-11-03-nk56-t19-approval-exercise/receipt.json

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+{
+  "schema": "netkingdom.bounded-executor.approval-exercise/v1",
+  "task": "NK-WP-0056-T19",
+  "target": "disposable local processes; synthetic keys and credentials",
+  "started_at": "2026-11-03T22:15:58+00:00",
+  "keycape_image": "forgejo.coulomb.social/coulomb/key-cape@sha256:9e082dca78f65a4af3e92d3de3705b99e49ca9b298d9562ad0d37511c4306f8d",
+  "issuer_contract_commit": "82b471fc368a952fa4bbe83e8c8cfcfe56c443b9",
+  "approval_engine_commit": "f41a9ca82ce0e491e7846c5e2ae33fcbd3bde667",
+  "net_kingdom_commit": "e1ef4bf6b19b211c62f4ff1ff5c430af78d64250",
+  "executor_source_sha256": {
+    "cli.py": "b6cb53a7c71a06c61daf02ff1740d065cd754b1b5d2640571cce2b3f44ad8ff2",
+    "clients.py": "f0ce580f1beba91b7154051a35c088205de01f26d63a119a23bd926fe1c772cb",
+    "executor.py": "3da69db9cdd0ba7241246204dd92a57a84779f078ea3cd6d2705f3a8cc11b544"
+  },
+  "case_sha256": "32ba48b4131e22c993bbf8e705bd4f371a0e11222b069279cd196f2b880003c5",
+  "keycape_client": {
+    "clientId": "nk-bind-executor-approval",
+    "audience": "approval-engine",
+    "allowedScopes": [
+      "approval:create",
+      "approval:read",
+      "approval:consume"
+    ],
+    "grantTypes": [
+      "client_credentials"
+    ],
+    "serviceSubject": "service:nk-bind-executor",
+    "tenant": "tenant:platform",
+    "tokenLifetime": "15m"
+  },
+  "limitations": [
+    "approval-engine runs from source in-process, not the deployed image",
+    "the founder's aal2 entry is seeded through approval-engine's store; no human PKCE login",
+    "the client secret is handed to the client directly; the OpenBao lane is covered by the T18 tests",
+    "no informed-decision presentation (T21 tests cover the memo against its real validator)",
+    "plain HTTP on loopback; production uses KeyCape's public HTTPS issuer"
+  ],
+  "checks": {
+    "request_phase_creates_as_executor_via_verified_keycape_jwt": true,
+    "create_with_another_actor_refused": true,
+    "preflight_refuses_unapproved": true,
+    "service_approve_of_human_control_refused": true,
+    "human_aal2_entry_approves": true,
+    "executor_preflight_accepts_keycape_aal2_entry": true,
+    "executor_consumes_once_and_confirms_by_read_back": true,
+    "same_digest_retry_idempotent": true,
+    "second_run_on_consumed_approval_refused_before_consume": true,
+    "different_digest_refused": true,
+    "changed_admission_refused_by_binding_digest": true,
+    "revoke_before_consume_refused_by_executor_and_engine": true,
+    "aal1_human_entry_refused_by_executor": true,
+    "executor_client_refused_approve_scope_by_issuer": true,
+    "token_for_another_scope_refused_by_engine": true,
+    "wrong_client_secret_refused": true
+  },
+  "status": "passed",
+  "cleanup_complete": true,
+  "finished_at": "2026-11-03T22:16:00+00:00"
+}