Restore discovery validation

docs/source/reference/cli.md

@@ -51,9 +51,11 @@ supports that capability. Docker validation uses two containers concurrently
 during the fresh-container replay. Both use the same immutable image and are
 removed even if a check fails.
 
-The runtime level implements startup, reward, observation, state, network policy,
-seed forwarding, determinism and emitted trajectory record checks. Other applicable
-Level 2 checks appear as `SKIP`; they make
+The 12 implemented runtime checks cover startup, rewards, observation schemas,
+state continuity, network policy, seed forwarding, determinism, emitted trajectory
+records, tool and task discovery, rubric introspection and reward attribution.
+Four checks remain unimplemented: host containment, resource bounds, episode
+isolation and oracle containment. Applicable unimplemented checks appear as `SKIP`; they make
 the result `WARN`, which exits zero and does not mean Level 2 is complete.
 `FAIL` exits 1, unsupported package formats exit 2, and internal or policy errors
 exit 3. `--level semantic`
@@ -68,7 +70,9 @@ the subject's namespace and from a control container; a probe counts only when
 the control reaches the sink, and a denial that is not proven is a `SKIP`.
 `--local` explicitly selects this default package mode and rejects a remote URL.
 Explicitly unsupported session telemetry yields a `SKIP` naming `session_telemetry`;
-authorization refusals and malformed telemetry remain failures. Seed control
+authorization refusals and malformed telemetry remain failures. Explicitly unsupported
+`tools/list` similarly skips with `tool_discovery` named. Internal discovery errors
+and malformed responses remain failures, even for an empty declared tool set. Seed control
 reports observed forwarding to reset, separately from empirical determinism.
 The declared `episode_timeout_s` bounds each episode; a reset or judged step may use
 its remaining budget. Original and replay collection share a 300-second deadline

rfcs/008-environment-auto-validation.md

@@ -660,6 +660,11 @@ evaluation flags. Unevaluated gated children never reuse an earlier score.
 Stock container aggregation is named explicitly; custom rubrics may supply
 `validation_config()` to expose public JSON configuration. Arbitrary attributes
 and `state_dict()` are never serialized as configuration.
+Attribution compares each numeric step reward with its freshly evaluated root
+score. Null non-terminal rewards have no emitted score to compare; their records
+must still have the correct identity, unchanged configuration, and valid evaluated
+aggregation. An entirely unscored episode is incomplete rather than passing
+attribution. Terminal null rewards remain invalid.
 
 The subject server also emits a bounded record of the reset/step/state request
 and response envelopes it executed. The validator captures the wire separately
@@ -668,6 +673,27 @@ limited to 100 steps/202 operations and 8 MiB, and marks truncation explicitly.
 Missing configuration, attribution or records cannot be inferred from other
 successful operations. This transport introduces no new passing grader by itself.
 
+#### Declaration and rubric evidence (PR6)
+
+The validator discovers MCP tools over the authenticated replay connection before
+reset and compares their names with the declaration, including an explicitly empty
+set. Task discovery queries split names and authoritative per-split counts, then
+reads at most two individual tasks per split. Preview length is never treated as
+the dataset size. Requests share the collection deadline and bounded response
+budgets; unavailable or malformed discovery cannot become an empty passing set.
+The task namespace comes from the server's single `/list_environments` entry,
+independently of the package name. Omitted tool/count declarations stay unknown;
+explicit `[]`/`{}` declarations assert zero tools/splits. A declared task API
+without declared counts leaves count accuracy incomplete.
+
+Rubric checks require the declared tree and explicit public configuration, then
+compare every observed step reward with its fresh root score and named child
+attribution. Built-in weighted, sequential and gated aggregation is checked using
+its published configuration. Unknown custom aggregation remains incomplete.
+Optional task and rubric checks are selected only when declared. `discovery.json`
+retains raw discovery results, availability and sanitized errors alongside session
+telemetry; ordinary discovery responses never enter the episode trajectory.
+
 Applicability predicates must distinguish empty declared sets from absent
 capabilities. Missing subject features, missing provider support and checks whose
 implementation has not shipped are distinct outcomes. Independent graders must

src/openenv/core/env_server/http_server.py

@@ -1258,7 +1258,7 @@ async def call_mcp_style_step(action: Action) -> Observation:
                                 request_id=request_id,
                             )
                         return JsonRpcResponse.error_response(
-                            JsonRpcErrorCode.INTERNAL_ERROR,
+                            JsonRpcErrorCode.METHOD_NOT_FOUND,
                             "Environment does not support MCP",
                             request_id=request_id,
                         )