diff --git a/docs/eve-migration-roadmap.md b/docs/eve-migration-roadmap.md
index 5730747..889e4f7 100644
--- a/docs/eve-migration-roadmap.md
+++ b/docs/eve-migration-roadmap.md
@@ -280,6 +280,14 @@ Exit criteria:
 
 Recently cut:
 
+- Aetheria interactive world surfaces now carry a structured provider-owned
+  `worldInteraction` contract. The provider advertisement names projection
+  kind, provider state schemas, daemon command boundary, receipt schema,
+  lowering targets, and ownership rules for `aetheria.daemon.game` and
+  `aetheria.daemon.editor`. The provider scenario requires the daemon game
+  world-surface contract, parity validates it against the advertisement, the
+  conformance export carries `surfaceContracts`, and the Aetheria consumer
+  smoke asserts those fields without importing Aetheria or Eve internals.
 - EveUnity test lifecycle now carries a structured Unity EditMode runner
   contract. `packages/org.gamecult.eve.unity-uitoolkit/eve-runtime-capability.json`
   names the runner script, consumer Unity project, default Unity editor path,
diff --git a/docs/provider-advertisement-contract.md b/docs/provider-advertisement-contract.md
index b4a9233..d13a2b3 100644
--- a/docs/provider-advertisement-contract.md
+++ b/docs/provider-advertisement-contract.md
@@ -78,6 +78,12 @@ Required top-level meanings:
   the advertised surface, schemas, and command boundary.
 - `surfaces[].interactionModel`: short name for how interaction returns to the
   provider, such as `provider-command-receipts`.
+- `surfaces[].worldInteraction`: optional structured contract for
+  provider-authored world surfaces. It names the projection kind, provider-owned
+  state schemas, command boundary, receipt schema, expected lowering targets,
+  and ownership rule. Runtimes use it to decide how to lower the surface and
+  where command intents must return; they do not gain authority over world
+  state because they can render it.
 - `surfaces[].requiresPlugins`: sidecar plugin capabilities required to render
   or interact with that surface. Runtimes compare these requirements with their
   local projection support and report visible capability gaps; they must not
diff --git a/docs/world-state-lowering.md b/docs/world-state-lowering.md
index 1158222..8efd0fb 100644
--- a/docs/world-state-lowering.md
+++ b/docs/world-state-lowering.md
@@ -76,6 +76,23 @@ World surfaces should be able to describe:
 The renderer chooses the best native projection it can support. It must not
 invent provider semantics to compensate for missing contract information.
 
+Provider advertisements attach the reusable boundary to world surfaces through
+`surfaces[].worldInteraction`. That block names:
+
+- `projectionKind`: the generic world presentation role, not a game-specific
+  rule name;
+- `stateSchemas`: provider-owned state documents that describe the world;
+- `commandBoundary`: the provider command route that receives interaction
+  intents;
+- `receiptSchema`: the provider-owned receipt document schema;
+- `loweringTargets`: runtime families expected to consume the surface;
+- `ownership`: the plain-language authority rule for state, assets, command
+  acceptance, and receipts.
+
+Conformance scenarios can require `worldSurfaces[]` entries and the parity
+harness checks them against the advertisement. This makes an interactive world
+surface portable without giving Eve or a runtime private Aetheria knowledge.
+
 ## Quality Tiers
 
 A low-end or debugging renderer may lower a world surface into labels, simple
@@ -120,6 +137,13 @@ missing a generic scalar-field primitive or the provider surface is
 underspecified. If a renderer must know "Aetheria planet" to draw a body, the
 object row or asset contract is underspecified.
 
+The incubating Aetheria fixture advertises `aetheria.daemon.game` as
+`interactive-world` with `worldInteraction.projectionKind:
+provider-authored-world-surface`, `commandBoundary: aetheria.daemon.commands`,
+and `receiptSchema: aetheria.eve_command_acceptance_status.v1`. Web, Unity UI
+Toolkit, Unity scene, and TUI lowerers are lowering targets; Aetheria remains
+the owner of world state, assets, command acceptance, and receipts.
+
 ## Non-Goals
 
 Eve does not own provider gameplay rules.
diff --git a/schemas/gamecult.eve.provider_advertisement.v1.schema.json b/schemas/gamecult.eve.provider_advertisement.v1.schema.json
index e298d3a..aaedac1 100644
--- a/schemas/gamecult.eve.provider_advertisement.v1.schema.json
+++ b/schemas/gamecult.eve.provider_advertisement.v1.schema.json
@@ -144,6 +144,50 @@
             "type": "string",
             "minLength": 1
           },
+          "worldInteraction": {
+            "type": "object",
+            "required": [
+              "projectionKind",
+              "stateSchemas",
+              "commandBoundary",
+              "receiptSchema",
+              "loweringTargets",
+              "ownership"
+            ],
+            "properties": {
+              "projectionKind": {
+                "type": "string",
+                "minLength": 1
+              },
+              "stateSchemas": {
+                "type": "array",
+                "items": {
+                  "type": "string",
+                  "minLength": 1
+                }
+              },
+              "commandBoundary": {
+                "type": "string",
+                "minLength": 1
+              },
+              "receiptSchema": {
+                "type": "string",
+                "minLength": 1
+              },
+              "loweringTargets": {
+                "type": "array",
+                "items": {
+                  "type": "string",
+                  "minLength": 1
+                }
+              },
+              "ownership": {
+                "type": "string",
+                "minLength": 1
+              }
+            },
+            "additionalProperties": true
+          },
           "requiresPlugins": {
             "type": "array",
             "items": {
diff --git a/schemas/gamecult.eve.provider_scenario.v1.schema.json b/schemas/gamecult.eve.provider_scenario.v1.schema.json
index c7828ca..fe94df1 100644
--- a/schemas/gamecult.eve.provider_scenario.v1.schema.json
+++ b/schemas/gamecult.eve.provider_scenario.v1.schema.json
@@ -51,6 +51,42 @@
             "minLength": 1
           }
         },
+        "worldSurfaces": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "required": [
+              "surfaceId",
+              "surfaceKind",
+              "projectionKind",
+              "commandBoundary",
+              "receiptSchema"
+            ],
+            "properties": {
+              "surfaceId": {
+                "type": "string",
+                "minLength": 1
+              },
+              "surfaceKind": {
+                "type": "string",
+                "minLength": 1
+              },
+              "projectionKind": {
+                "type": "string",
+                "minLength": 1
+              },
+              "commandBoundary": {
+                "type": "string",
+                "minLength": 1
+              },
+              "receiptSchema": {
+                "type": "string",
+                "minLength": 1
+              }
+            },
+            "additionalProperties": true
+          }
+        },
         "commands": {
           "type": "array",
           "items": {
diff --git a/scripts/run-aetheria-conformance-consumer-smoke.ps1 b/scripts/run-aetheria-conformance-consumer-smoke.ps1
index f7f8c34..96b8b6b 100644
--- a/scripts/run-aetheria-conformance-consumer-smoke.ps1
+++ b/scripts/run-aetheria-conformance-consumer-smoke.ps1
@@ -45,6 +45,13 @@ try {
     --expect-provider-surface aetheria:aetheria.daemon.editor `
     --expect-provider-surface-kind aetheria:aetheria.daemon.game:interactive-world `
     --expect-provider-surface-kind aetheria:aetheria.daemon.editor:interactive-world-editor `
+    --expect-provider-surface-field aetheria:aetheria.daemon.game:worldInteraction.projectionKind:provider-authored-world-surface `
+    --expect-provider-surface-field aetheria:aetheria.daemon.game:worldInteraction.commandBoundary:aetheria.daemon.commands `
+    --expect-provider-surface-field aetheria:aetheria.daemon.game:worldInteraction.receiptSchema:aetheria.eve_command_acceptance_status.v1 `
+    --expect-provider-surface-field aetheria:aetheria.daemon.game:worldInteraction.ownership:provider-owns-world-state-assets-command-acceptance-and-receipts `
+    --expect-provider-surface-field aetheria:aetheria.daemon.editor:worldInteraction.projectionKind:provider-authored-world-editor-surface `
+    --expect-provider-surface-field aetheria:aetheria.daemon.editor:worldInteraction.commandBoundary:aetheria.daemon.commands `
+    --expect-provider-surface-field aetheria:aetheria.daemon.editor:worldInteraction.receiptSchema:aetheria.eve_command_acceptance_status.v1 `
     --expect-provider-command aetheria:aetheria.daemon.commands `
     --expect-provider-receipt-state aetheria:accepted `
     --expect-provider-receipt-state aetheria:reconciled `
diff --git a/scripts/run-aetheria-provider-handoff-smoke.ps1 b/scripts/run-aetheria-provider-handoff-smoke.ps1
index 06098e3..c35da36 100644
--- a/scripts/run-aetheria-provider-handoff-smoke.ps1
+++ b/scripts/run-aetheria-provider-handoff-smoke.ps1
@@ -54,6 +54,30 @@ if ($scenario.ownerRepo -ne $handoff.ownerRepo) {
   throw "Aetheria scenario owner does not match handoff owner: $($scenario.ownerRepo)"
 }
 
+$worldSurfaces = @{}
+foreach ($surface in @($advertisement.surfaces)) {
+  if ($surface.surfaceId -and $surface.worldInteraction) {
+    $worldSurfaces[$surface.surfaceId] = $surface
+  }
+}
+foreach ($requirement in @($scenario.requires.worldSurfaces)) {
+  if (-not $worldSurfaces.ContainsKey($requirement.surfaceId)) {
+    throw "Aetheria scenario requires world surface not advertised with worldInteraction: $($requirement.surfaceId)"
+  }
+  $advertisedSurface = $worldSurfaces[$requirement.surfaceId]
+  if ($advertisedSurface.surfaceKind -ne $requirement.surfaceKind) {
+    throw "Aetheria world surface kind mismatch for $($requirement.surfaceId): $($advertisedSurface.surfaceKind)"
+  }
+  foreach ($property in @("projectionKind", "commandBoundary", "receiptSchema")) {
+    if ($advertisedSurface.worldInteraction.$property -ne $requirement.$property) {
+      throw "Aetheria world surface $($requirement.surfaceId) $property mismatch: $($advertisedSurface.worldInteraction.$property)"
+    }
+  }
+  if (-not $advertisedSurface.worldInteraction.ownership) {
+    throw "Aetheria world surface $($requirement.surfaceId) missing ownership rule"
+  }
+}
+
 foreach ($fixtureId in @($handoff.fixtureIds)) {
   if (-not (@($scenario.requires.fixtures) -contains $fixtureId)) {
     throw "Aetheria provider handoff fixture is not required by scenario: $fixtureId"
diff --git a/tools/conformance/consume-export.mjs b/tools/conformance/consume-export.mjs
index bd37067..be367d3 100644
--- a/tools/conformance/consume-export.mjs
+++ b/tools/conformance/consume-export.mjs
@@ -28,6 +28,7 @@ if (!exportDirectory) {
     "  --expect-plugin-handoff <pluginId>",
     "  --expect-provider-surface <providerId:surfaceId>",
     "  --expect-provider-surface-kind <providerId:surfaceId:surfaceKind>",
+    "  --expect-provider-surface-field <providerId:surfaceId:field.path:value>",
     "  --expect-provider-command <providerId:command>",
     "  --expect-provider-receipt-state <providerId:state>",
     "  --expect-provider-handoff <providerId>",
@@ -239,6 +240,23 @@ function validateIndex(index, directory, expectations, errors) {
       errors.push(`providers:${expectation.providerId}:surfaceKind:${expectation.surfaceId}:expected ${expectation.surfaceKind} got ${surface.surfaceKind || ""}`);
     }
   }
+  for (const expectation of expectations.providerSurfaceFields) {
+    const provider = providers.find(candidate => candidate.providerId === expectation.providerId);
+    if (!provider) {
+      errors.push(`providers:${expectation.providerId}:missing`);
+      continue;
+    }
+    const surfaceContracts = Array.isArray(provider.surfaceContracts) ? provider.surfaceContracts : [];
+    const surface = surfaceContracts.find(candidate => candidate.surfaceId === expectation.surfaceId);
+    if (!surface) {
+      errors.push(`providers:${expectation.providerId}:surfaceContract:${expectation.surfaceId}:missing`);
+      continue;
+    }
+    const actual = readNestedField(surface, expectation.fieldPath);
+    if (actual !== expectation.value) {
+      errors.push(`providers:${expectation.providerId}:surfaceContract:${expectation.surfaceId}.${expectation.fieldPath}:expected ${expectation.value} got ${actual || ""}`);
+    }
+  }
   for (const expectation of expectations.providerCommands) {
     const provider = providers.find(candidate => candidate.providerId === expectation.providerId);
     if (!provider) {
@@ -514,6 +532,7 @@ function parseArguments(args) {
     providers: [],
     providerSurfaces: [],
     providerSurfaceKinds: [],
+    providerSurfaceFields: [],
     providerCommands: [],
     providerReceiptStates: [],
     providerHandoffs: [],
@@ -552,6 +571,7 @@ function parseArguments(args) {
     ["--expect-plugin-handoff", expectations.pluginHandoffs],
     ["--expect-provider-surface", expectations.providerSurfaces],
     ["--expect-provider-surface-kind", expectations.providerSurfaceKinds],
+    ["--expect-provider-surface-field", expectations.providerSurfaceFields],
     ["--expect-provider-command", expectations.providerCommands],
     ["--expect-provider-receipt-state", expectations.providerReceiptStates],
     ["--expect-provider-handoff", expectations.providerHandoffs],
@@ -607,6 +627,8 @@ function parseArguments(args) {
       target.push(parseProviderExpectation(value, "surfaceId"));
     } else if (option === "--expect-provider-surface-kind") {
       target.push(parseProviderSurfaceKindExpectation(value));
+    } else if (option === "--expect-provider-surface-field") {
+      target.push(parseProviderSurfaceFieldExpectation(value));
     } else if (option === "--expect-provider-command") {
       target.push(parseProviderExpectation(value, "command"));
     } else if (option === "--expect-provider-receipt-state") {
@@ -669,6 +691,20 @@ function parsePluginRuntimeFieldExpectation(value) {
   };
 }
 
+function parseProviderSurfaceFieldExpectation(value) {
+  const parts = value.split(":");
+  if (parts.length < 4 || !parts[0] || !parts[1] || !parts[2] || !parts.slice(3).join(":")) {
+    console.error(`Expected provider surface field in <providerId:surfaceId:field.path:value> form, got: ${value}`);
+    process.exit(2);
+  }
+  return {
+    providerId: parts[0],
+    surfaceId: parts[1],
+    fieldPath: parts[2],
+    value: parts.slice(3).join(":"),
+  };
+}
+
 function parseProviderExpectation(value, field) {
   const separator = value.indexOf(":");
   if (separator <= 0 || separator === value.length - 1) {
diff --git a/tools/parity/run-parity.mjs b/tools/parity/run-parity.mjs
index 3317f6e..0c45811 100644
--- a/tools/parity/run-parity.mjs
+++ b/tools/parity/run-parity.mjs
@@ -629,6 +629,7 @@ async function evaluateProvider(provider, fixtureResults, pluginResults) {
   ])].sort() : [];
   const surfaceIds = advertisement ? (advertisement.surfaces || []).map(surface => surface.surfaceId).filter(Boolean).sort() : [];
   const surfaceKinds = advertisement ? collectProviderSurfaceKinds(advertisement) : [];
+  const surfaceContracts = advertisement ? collectProviderSurfaceContracts(advertisement) : [];
   const commandIds = advertisement ? (advertisement.commands || []).map(command => command.command).filter(Boolean).sort() : [];
   const witnessKinds = advertisement ? (advertisement.witnesses || []).map(witness => witness.kind).filter(Boolean).sort() : [];
   const pluginRequirements = advertisement ? collectProviderPluginRequirements(advertisement) : [];
@@ -679,6 +680,7 @@ async function evaluateProvider(provider, fixtureResults, pluginResults) {
     advertisedSchemaIds,
     surfaceIds,
     surfaceKinds,
+    surfaceContracts,
     commandIds,
     witnessKinds,
     pluginRequirements,
@@ -720,6 +722,18 @@ function collectProviderSurfaceKinds(advertisement) {
     .sort((left, right) => left.surfaceId.localeCompare(right.surfaceId));
 }
 
+function collectProviderSurfaceContracts(advertisement) {
+  return (advertisement.surfaces || [])
+    .filter(surface => surface.surfaceId && surface.worldInteraction)
+    .map(surface => ({
+      surfaceId: surface.surfaceId,
+      surfaceKind: surface.surfaceKind || "",
+      interactionModel: surface.interactionModel || "",
+      worldInteraction: surface.worldInteraction || {},
+    }))
+    .sort((left, right) => left.surfaceId.localeCompare(right.surfaceId));
+}
+
 function validateProviderSurfaceKinds(provider, surfaceKinds) {
   const errors = [];
   const kindsBySurface = new Map(surfaceKinds.map(surface => [surface.surfaceId, surface.surfaceKind]));
@@ -797,6 +811,25 @@ async function validateProviderScenario(provider, advertisement, fixtureResults,
     errors.push(...missingMembers(scenario.requires?.surfaces || [], surfaceIds, `${provider.scenarioPath}:requires.surfaces`));
     errors.push(...missingMembers(scenario.requires?.commands || [], commandIds, `${provider.scenarioPath}:requires.commands`));
     errors.push(...missingMembers(scenario.requires?.schemas || [], advertisedSchemaIds, `${provider.scenarioPath}:requires.schemas`));
+    const advertisedWorldSurfaces = new Map((advertisement.surfaces || [])
+      .filter(surface => surface.surfaceId && surface.worldInteraction)
+      .map(surface => [surface.surfaceId, surface]));
+    for (const requirement of scenario.requires?.worldSurfaces || []) {
+      const advertisedSurface = advertisedWorldSurfaces.get(requirement.surfaceId);
+      if (!advertisedSurface) {
+        errors.push(`${provider.scenarioPath}:requires.worldSurfaces:${requirement.surfaceId}:missing`);
+        continue;
+      }
+      if (advertisedSurface.surfaceKind !== requirement.surfaceKind) {
+        errors.push(`${provider.scenarioPath}:requires.worldSurfaces:${requirement.surfaceId}:surfaceKind:expected ${requirement.surfaceKind} got ${advertisedSurface.surfaceKind || ""}`);
+      }
+      for (const key of ["projectionKind", "commandBoundary", "receiptSchema"]) {
+        const actual = advertisedSurface.worldInteraction?.[key] || "";
+        if (actual !== requirement[key]) {
+          errors.push(`${provider.scenarioPath}:requires.worldSurfaces:${requirement.surfaceId}:${key}:expected ${requirement[key]} got ${actual}`);
+        }
+      }
+    }
 
     const receipts = scenario.expectedReceipts || [];
     const receiptKeys = new Set(receipts.map(receipt => `${receipt.command}:${receipt.commandId}`));
@@ -1548,6 +1581,7 @@ function buildConformanceExport(report) {
       receiptStates: provider.scenarioReceiptStates || [],
       surfaces: provider.surfaceIds,
       surfaceKinds: provider.surfaceKinds,
+      surfaceContracts: provider.surfaceContracts,
       commands: provider.commandIds,
       pluginRequirements: provider.pluginRequirements,
     })),
@@ -1599,6 +1633,7 @@ function buildCapabilityMatrix(report) {
     status: provider.status,
     surfaces: provider.surfaceIds || [],
     surfaceKinds: provider.surfaceKinds || [],
+    surfaceContracts: provider.surfaceContracts || [],
     commands: provider.commandIds || [],
     receiptStates: provider.scenarioReceiptStates || [],
     handoffExportPath: makeHandoffExportPath("provider", provider.providerId, provider.handoffPath),
diff --git a/web/fixtures/aetheria-world-scenario.json b/web/fixtures/aetheria-world-scenario.json
index cc92b93..cb7bf4d 100644
--- a/web/fixtures/aetheria-world-scenario.json
+++ b/web/fixtures/aetheria-world-scenario.json
@@ -9,6 +9,15 @@
   "requires": {
     "fixtures": ["aetheria-world"],
     "surfaces": ["aetheria.daemon.game"],
+    "worldSurfaces": [
+      {
+        "surfaceId": "aetheria.daemon.game",
+        "surfaceKind": "interactive-world",
+        "projectionKind": "provider-authored-world-surface",
+        "commandBoundary": "aetheria.daemon.commands",
+        "receiptSchema": "aetheria.eve_command_acceptance_status.v1"
+      }
+    ],
     "commands": ["aetheria.daemon.commands"],
     "schemas": ["gamecult.eve.surface.v1", "gamecult.eve.command.v1", "aetheria.eve_command_acceptance_status.v1"]
   },
diff --git a/web/fixtures/aetheria-world-surface.conformance.json b/web/fixtures/aetheria-world-surface.conformance.json
index 575725a..4b4d2b4 100644
--- a/web/fixtures/aetheria-world-surface.conformance.json
+++ b/web/fixtures/aetheria-world-surface.conformance.json
@@ -14,6 +14,7 @@
     "field.surface2d world projection",
     "daemon command boundary",
     "provider-owned bindings",
+    "provider-advertised world interaction contract",
     "Aetheria style tokens"
   ],
   "splitTarget": "Aetheria"
diff --git a/web/fixtures/aetheria.provider-advertisement.json b/web/fixtures/aetheria.provider-advertisement.json
index 0bc5abe..59bf2cb 100644
--- a/web/fixtures/aetheria.provider-advertisement.json
+++ b/web/fixtures/aetheria.provider-advertisement.json
@@ -96,6 +96,18 @@
       "mode": "interactive",
       "surfaceKind": "interactive-world",
       "interactionModel": "provider-command-receipts",
+      "worldInteraction": {
+        "projectionKind": "provider-authored-world-surface",
+        "stateSchemas": [
+          "aetheria.world_state.v1",
+          "aetheria.runtime.daemon.frame.v1",
+          "aetheria.runtime.daemon.soa_view.v1"
+        ],
+        "commandBoundary": "aetheria.daemon.commands",
+        "receiptSchema": "aetheria.eve_command_acceptance_status.v1",
+        "loweringTargets": ["web-reference", "unity-uitoolkit", "unity-scene", "tui"],
+        "ownership": "provider-owns-world-state-assets-command-acceptance-and-receipts"
+      },
       "summary": "Authoritative daemon game surface consumed by Unity and web lowerers."
     },
     {
@@ -116,7 +128,19 @@
       "audience": "operator",
       "mode": "interactive",
       "surfaceKind": "interactive-world-editor",
-      "interactionModel": "provider-command-receipts"
+      "interactionModel": "provider-command-receipts",
+      "worldInteraction": {
+        "projectionKind": "provider-authored-world-editor-surface",
+        "stateSchemas": [
+          "aetheria.world_state.v1",
+          "aetheria.runtime.daemon.editor_surface.v1",
+          "aetheria.runtime.daemon.command_boundary.v1"
+        ],
+        "commandBoundary": "aetheria.daemon.commands",
+        "receiptSchema": "aetheria.eve_command_acceptance_status.v1",
+        "loweringTargets": ["web-reference", "unity-uitoolkit", "tui"],
+        "ownership": "provider-owns-editor-state-assets-command-acceptance-and-receipts"
+      }
     }
   ],
   "commands": [