Document published evidence context

docs/integrations/evidence-context.md

@@ -0,0 +1,116 @@
+# Published Evidence Context
+
+This contract defines the optional `source/evidence-context` artifact emitted
+by the production JSON output. Its configuration is owned by
+[Configuration](../config.md#module-bindings-and-validators); its logical-file
+discovery is owned by [Published JSON Output](json-output.md).
+
+## Identity And Discovery
+
+When enabled, the JSON bundle contains `evidence-context.json` and an
+`index.json` `evidence_context` descriptor with the same six fields as other
+pipeline-wide artifact descriptors.
+
+| Property | Value |
+| --- | --- |
+| Artifact kind | `source/evidence-context` |
+| Media type | `application/json` |
+| Schema ID | `notarius.source.evidence_context` |
+| Schema name | `notarius_source_evidence_context_v1` |
+| Schema version | `v1` |
+| Logical file | `evidence-context.json` |
+
+Consumers must discover the file from the descriptor, verify all six descriptor
+fields, and decode only a supported schema version. The descriptor is optional:
+its absence means evidence publication was not enabled for that bundle.
+
+## Payload
+
+The v1 payload is a JSON object with required `source_id`, `source_digest`,
+`window_units`, `selected_lanes`, and `contexts` fields. `selected_lanes` and
+`contexts` are always arrays; an enabled configuration with no accepted direct
+evidence publishes `contexts: []`.
+
+```json
+{
+  "source_id": "session-alpha",
+  "source_digest": "sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
+  "window_units": 1,
+  "selected_lanes": ["npcs", "spells"],
+  "contexts": [
+    {
+      "context_ref": {
+        "source_id": "session-alpha",
+        "start_unit_id": 10,
+        "end_unit_id": 20
+      },
+      "evidence_refs": [
+        {
+          "lane_id": "spells",
+          "source_ref": {
+            "source_id": "session-alpha",
+            "start_unit_id": 10,
+            "end_unit_id": 10
+          }
+        }
+      ],
+      "units": [
+        {
+          "id": 10,
+          "kind": "transcript_segment",
+          "text": "Aria casts Cure Wounds.",
+          "ref": {
+            "source_id": "session-alpha",
+            "start_unit_id": 10,
+            "end_unit_id": 10
+          }
+        },
+        {
+          "id": 20,
+          "kind": "transcript_segment",
+          "text": "The party regroups.",
+          "ref": {
+            "source_id": "session-alpha",
+            "start_unit_id": 20,
+            "end_unit_id": 20
+          }
+        }
+      ]
+    }
+  ]
+}
+```
+
+Each context requires `context_ref`, `evidence_refs`, and `units` arrays.
+`context_ref` identifies the first and last included unit. Each evidence entry
+contains a selected `lane_id` and an original `source_ref`. A unit uses the
+existing source-unit shape: required `id`, `kind`, `text`, and self `ref`, plus
+optional JSON-object `metadata`. Fixed payload objects reject unknown fields;
+unit metadata may contain application-defined JSON values.
+
+## Citations And Context
+
+`evidence_refs` are the authoritative citations. They identify the direct
+references emitted by accepted normalized artifacts. `context_ref` and the
+units collection include those cited units plus nearby source units selected by
+the configured window. They are explanatory context, not widened citations.
+
+Only accepted outputs from the configured lane allowlist contribute. Rejected,
+failed, absent, and lane-filtered outputs do not contribute. The artifact never
+contains raw input bytes, prompts, model responses, auxiliary reference
+content, credentials, or filesystem paths.
+
+## Ordering And Compatibility
+
+The selected lane allowlist is lexical. Contexts and units are in source
+document position order, not numeric unit-ID order. Direct evidence entries
+are deterministically ordered by lane and source reference. Overlapping or
+contiguous windows merge, and each source unit appears at most once in the
+resulting contexts.
+
+The artifact is additive to the JSON bundle and is not a lane payload,
+normalized-output count, checkpoint, or generated reference. Consumers that
+do not need it must tolerate the absent optional descriptor. Consumers that do
+use it should preserve the artifact and its schema identity with the run
+provenance, and should treat its source text and metadata as sensitive durable
+content.