diff --git a/.changeset/activity-contributor-legacy-strings.md b/.changeset/activity-contributor-legacy-strings.md
new file mode 100644
index 0000000..64e05f9
--- /dev/null
+++ b/.changeset/activity-contributor-legacy-strings.md
@@ -0,0 +1,5 @@
+---
+'@hypercerts-org/hypercerts-api': patch
+---
+
+Activity responses now tolerate legacy contributor URI strings without failing hydration. The original activity record is preserved, while those strings are omitted from the hydrated `contributors` projection.
diff --git a/api/lexicons/org.hypercerts.claim.getActivity.json b/api/lexicons/org.hypercerts.claim.getActivity.json
index 96f08c2..a47a9b3 100644
--- a/api/lexicons/org.hypercerts.claim.getActivity.json
+++ b/api/lexicons/org.hypercerts.claim.getActivity.json
@@ -47,7 +47,7 @@
         "record": { "type": "ref", "ref": "org.hypercerts.claim.activity" },
         "contributors": {
           "type": "array",
-          "description": "Hydrated contributor projection in the same order and with the same multiplicity as record.contributors; omitted only when the source field is absent.",
+          "description": "Hydrated projection of object entries in record.contributors, preserving their relative order and multiplicity; legacy string entries are skipped and the original record remains unchanged. Omitted only when the source field is absent; if it contains no object entries, this is an empty array.",
           "items": { "type": "ref", "ref": "#activityContributorView" }
         }
       }
diff --git a/api/lua/endpoints/getActivity.lua b/api/lua/endpoints/getActivity.lua
index d06ab44..0841bac 100644
--- a/api/lua/endpoints/getActivity.lua
+++ b/api/lua/endpoints/getActivity.lua
@@ -129,26 +129,28 @@ local function activity_projection_hydrate_views(views)
         error("ActivityQueryFailed: activity contributors are not an array", 0)
       end
       local projections = {}
-      for contributor_index, source in ipairs(source_contributors) do
-        local projection = {}
-        for key, value in pairs(source) do projection[key] = value end
-        projection.contributorInformation = ACTIVITY_PROJECTION_NULL
-        projection.actor = ACTIVITY_PROJECTION_NULL
-        projections[contributor_index] = projection
-
-        local identity = source.contributorIdentity
-        local resolution = { projection = projection }
-        if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
-          local key = activity_projection_identity_key(identity.uri, identity.cid)
-          resolution.information_key = key
-          if not seen_references[key] then
-            seen_references[key] = true
-            references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+      for _, source in ipairs(source_contributors) do
+        if type(source) ~= "string" then
+          local projection = {}
+          for key, value in pairs(source) do projection[key] = value end
+          projection.contributorInformation = ACTIVITY_PROJECTION_NULL
+          projection.actor = ACTIVITY_PROJECTION_NULL
+          projections[#projections + 1] = projection
+
+          local identity = source.contributorIdentity
+          local resolution = { projection = projection }
+          if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
+            local key = activity_projection_identity_key(identity.uri, identity.cid)
+            resolution.information_key = key
+            if not seen_references[key] then
+              seen_references[key] = true
+              references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+            end
+          elseif type(identity) == "table" then
+            resolution.identifier = identity.identity
           end
-        elseif type(identity) == "table" then
-          resolution.identifier = identity.identity
+          contributor_resolutions[#contributor_resolutions + 1] = resolution
         end
-        contributor_resolutions[#contributor_resolutions + 1] = resolution
       end
       projected_contributors[view_index] = projections
     end
diff --git a/api/lua/endpoints/listActivities.lua b/api/lua/endpoints/listActivities.lua
index 0023c12..c43e79f 100644
--- a/api/lua/endpoints/listActivities.lua
+++ b/api/lua/endpoints/listActivities.lua
@@ -129,26 +129,28 @@ local function activity_projection_hydrate_views(views)
         error("ActivityQueryFailed: activity contributors are not an array", 0)
       end
       local projections = {}
-      for contributor_index, source in ipairs(source_contributors) do
-        local projection = {}
-        for key, value in pairs(source) do projection[key] = value end
-        projection.contributorInformation = ACTIVITY_PROJECTION_NULL
-        projection.actor = ACTIVITY_PROJECTION_NULL
-        projections[contributor_index] = projection
-
-        local identity = source.contributorIdentity
-        local resolution = { projection = projection }
-        if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
-          local key = activity_projection_identity_key(identity.uri, identity.cid)
-          resolution.information_key = key
-          if not seen_references[key] then
-            seen_references[key] = true
-            references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+      for _, source in ipairs(source_contributors) do
+        if type(source) ~= "string" then
+          local projection = {}
+          for key, value in pairs(source) do projection[key] = value end
+          projection.contributorInformation = ACTIVITY_PROJECTION_NULL
+          projection.actor = ACTIVITY_PROJECTION_NULL
+          projections[#projections + 1] = projection
+
+          local identity = source.contributorIdentity
+          local resolution = { projection = projection }
+          if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
+            local key = activity_projection_identity_key(identity.uri, identity.cid)
+            resolution.information_key = key
+            if not seen_references[key] then
+              seen_references[key] = true
+              references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+            end
+          elseif type(identity) == "table" then
+            resolution.identifier = identity.identity
           end
-        elseif type(identity) == "table" then
-          resolution.identifier = identity.identity
+          contributor_resolutions[#contributor_resolutions + 1] = resolution
         end
-        contributor_resolutions[#contributor_resolutions + 1] = resolution
       end
       projected_contributors[view_index] = projections
     end
diff --git a/api/lua/endpoints/listCollectionItems.lua b/api/lua/endpoints/listCollectionItems.lua
index 747b416..68d559f 100644
--- a/api/lua/endpoints/listCollectionItems.lua
+++ b/api/lua/endpoints/listCollectionItems.lua
@@ -150,26 +150,28 @@ local function activity_projection_hydrate_views(views)
         error("ActivityQueryFailed: activity contributors are not an array", 0)
       end
       local projections = {}
-      for contributor_index, source in ipairs(source_contributors) do
-        local projection = {}
-        for key, value in pairs(source) do projection[key] = value end
-        projection.contributorInformation = ACTIVITY_PROJECTION_NULL
-        projection.actor = ACTIVITY_PROJECTION_NULL
-        projections[contributor_index] = projection
-
-        local identity = source.contributorIdentity
-        local resolution = { projection = projection }
-        if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
-          local key = activity_projection_identity_key(identity.uri, identity.cid)
-          resolution.information_key = key
-          if not seen_references[key] then
-            seen_references[key] = true
-            references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+      for _, source in ipairs(source_contributors) do
+        if type(source) ~= "string" then
+          local projection = {}
+          for key, value in pairs(source) do projection[key] = value end
+          projection.contributorInformation = ACTIVITY_PROJECTION_NULL
+          projection.actor = ACTIVITY_PROJECTION_NULL
+          projections[#projections + 1] = projection
+
+          local identity = source.contributorIdentity
+          local resolution = { projection = projection }
+          if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
+            local key = activity_projection_identity_key(identity.uri, identity.cid)
+            resolution.information_key = key
+            if not seen_references[key] then
+              seen_references[key] = true
+              references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+            end
+          elseif type(identity) == "table" then
+            resolution.identifier = identity.identity
           end
-        elseif type(identity) == "table" then
-          resolution.identifier = identity.identity
+          contributor_resolutions[#contributor_resolutions + 1] = resolution
         end
-        contributor_resolutions[#contributor_resolutions + 1] = resolution
       end
       projected_contributors[view_index] = projections
     end
diff --git a/api/lua/endpoints/listEntityFollowing.lua b/api/lua/endpoints/listEntityFollowing.lua
index 70f55be..7848983 100644
--- a/api/lua/endpoints/listEntityFollowing.lua
+++ b/api/lua/endpoints/listEntityFollowing.lua
@@ -192,26 +192,28 @@ local function activity_projection_hydrate_views(views)
         error("ActivityQueryFailed: activity contributors are not an array", 0)
       end
       local projections = {}
-      for contributor_index, source in ipairs(source_contributors) do
-        local projection = {}
-        for key, value in pairs(source) do projection[key] = value end
-        projection.contributorInformation = ACTIVITY_PROJECTION_NULL
-        projection.actor = ACTIVITY_PROJECTION_NULL
-        projections[contributor_index] = projection
-
-        local identity = source.contributorIdentity
-        local resolution = { projection = projection }
-        if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
-          local key = activity_projection_identity_key(identity.uri, identity.cid)
-          resolution.information_key = key
-          if not seen_references[key] then
-            seen_references[key] = true
-            references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+      for _, source in ipairs(source_contributors) do
+        if type(source) ~= "string" then
+          local projection = {}
+          for key, value in pairs(source) do projection[key] = value end
+          projection.contributorInformation = ACTIVITY_PROJECTION_NULL
+          projection.actor = ACTIVITY_PROJECTION_NULL
+          projections[#projections + 1] = projection
+
+          local identity = source.contributorIdentity
+          local resolution = { projection = projection }
+          if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
+            local key = activity_projection_identity_key(identity.uri, identity.cid)
+            resolution.information_key = key
+            if not seen_references[key] then
+              seen_references[key] = true
+              references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+            end
+          elseif type(identity) == "table" then
+            resolution.identifier = identity.identity
           end
-        elseif type(identity) == "table" then
-          resolution.identifier = identity.identity
+          contributor_resolutions[#contributor_resolutions + 1] = resolution
         end
-        contributor_resolutions[#contributor_resolutions + 1] = resolution
       end
       projected_contributors[view_index] = projections
     end
diff --git a/api/lua/endpoints/searchActivities.lua b/api/lua/endpoints/searchActivities.lua
index 58e4fcc..4040250 100644
--- a/api/lua/endpoints/searchActivities.lua
+++ b/api/lua/endpoints/searchActivities.lua
@@ -129,26 +129,28 @@ local function activity_projection_hydrate_views(views)
         error("ActivityQueryFailed: activity contributors are not an array", 0)
       end
       local projections = {}
-      for contributor_index, source in ipairs(source_contributors) do
-        local projection = {}
-        for key, value in pairs(source) do projection[key] = value end
-        projection.contributorInformation = ACTIVITY_PROJECTION_NULL
-        projection.actor = ACTIVITY_PROJECTION_NULL
-        projections[contributor_index] = projection
-
-        local identity = source.contributorIdentity
-        local resolution = { projection = projection }
-        if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
-          local key = activity_projection_identity_key(identity.uri, identity.cid)
-          resolution.information_key = key
-          if not seen_references[key] then
-            seen_references[key] = true
-            references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+      for _, source in ipairs(source_contributors) do
+        if type(source) ~= "string" then
+          local projection = {}
+          for key, value in pairs(source) do projection[key] = value end
+          projection.contributorInformation = ACTIVITY_PROJECTION_NULL
+          projection.actor = ACTIVITY_PROJECTION_NULL
+          projections[#projections + 1] = projection
+
+          local identity = source.contributorIdentity
+          local resolution = { projection = projection }
+          if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
+            local key = activity_projection_identity_key(identity.uri, identity.cid)
+            resolution.information_key = key
+            if not seen_references[key] then
+              seen_references[key] = true
+              references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+            end
+          elseif type(identity) == "table" then
+            resolution.identifier = identity.identity
           end
-        elseif type(identity) == "table" then
-          resolution.identifier = identity.identity
+          contributor_resolutions[#contributor_resolutions + 1] = resolution
         end
-        contributor_resolutions[#contributor_resolutions + 1] = resolution
       end
       projected_contributors[view_index] = projections
     end
diff --git a/api/lua/shared/activityProjection.lua b/api/lua/shared/activityProjection.lua
index 3f7870b..12ee77e 100644
--- a/api/lua/shared/activityProjection.lua
+++ b/api/lua/shared/activityProjection.lua
@@ -109,26 +109,28 @@ local function activity_projection_hydrate_views(views)
         error("ActivityQueryFailed: activity contributors are not an array", 0)
       end
       local projections = {}
-      for contributor_index, source in ipairs(source_contributors) do
-        local projection = {}
-        for key, value in pairs(source) do projection[key] = value end
-        projection.contributorInformation = ACTIVITY_PROJECTION_NULL
-        projection.actor = ACTIVITY_PROJECTION_NULL
-        projections[contributor_index] = projection
+      for _, source in ipairs(source_contributors) do
+        if type(source) ~= "string" then
+          local projection = {}
+          for key, value in pairs(source) do projection[key] = value end
+          projection.contributorInformation = ACTIVITY_PROJECTION_NULL
+          projection.actor = ACTIVITY_PROJECTION_NULL
+          projections[#projections + 1] = projection
 
-        local identity = source.contributorIdentity
-        local resolution = { projection = projection }
-        if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
-          local key = activity_projection_identity_key(identity.uri, identity.cid)
-          resolution.information_key = key
-          if not seen_references[key] then
-            seen_references[key] = true
-            references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+          local identity = source.contributorIdentity
+          local resolution = { projection = projection }
+          if type(identity) == "table" and type(identity.uri) == "string" and type(identity.cid) == "string" then
+            local key = activity_projection_identity_key(identity.uri, identity.cid)
+            resolution.information_key = key
+            if not seen_references[key] then
+              seen_references[key] = true
+              references[#references + 1] = { uri = identity.uri, cid = identity.cid }
+            end
+          elseif type(identity) == "table" then
+            resolution.identifier = identity.identity
           end
-        elseif type(identity) == "table" then
-          resolution.identifier = identity.identity
+          contributor_resolutions[#contributor_resolutions + 1] = resolution
         end
-        contributor_resolutions[#contributor_resolutions + 1] = resolution
       end
       projected_contributors[view_index] = projections
     end
diff --git a/api/tests/unit/tooling/activity.test.js b/api/tests/unit/tooling/activity.test.js
index fcdb083..340e987 100644
--- a/api/tests/unit/tooling/activity.test.js
+++ b/api/tests/unit/tooling/activity.test.js
@@ -231,6 +231,38 @@ test('getActivity serializes a null activity indexed_at as explicit JSON null',
   assert.equal(body.activity.indexedAt, null);
 });
 
+test('getActivity skips legacy string contributors in a dense projection and preserves the source record', () => {
+  const legacyUris = [
+    'at://did:web:legacy-one.invalid/org.hypercerts.claim.contributorInformation/old',
+    'at://did:web:legacy-two.invalid/org.hypercerts.claim.contributorInformation/older',
+  ];
+  const mixedRecord = {
+    $type: ACTIVITY,
+    title: 'Legacy contributors',
+    createdAt: indexedAt,
+    contributors: [
+      legacyUris[0],
+      { contributorIdentity: { identity: contributorDid }, contributionWeight: 'first object' },
+      legacyUris[1],
+      { contributorIdentity: { identity: contributorDid }, contributionWeight: 'second object' },
+    ],
+  };
+  const mixed = runGetActivity({ recordJson: mixedRecord, serialize: true });
+  assert.equal(mixed.status, 0, `${mixed.stderr}${mixed.stdout}`);
+  const mixedActivity = JSON.parse(mixed.stdout).activity;
+  assert.deepEqual(mixedActivity.record, mixedRecord);
+  assert.deepEqual(mixedActivity.contributors.map(({ contributionWeight }) => contributionWeight), ['first object', 'second object']);
+  assert.deepEqual(mixedActivity.contributors.map(({ actor }) => actor.did), [contributorDid, contributorDid]);
+  assert.deepEqual(mixedActivity.contributors.map(({ actor }) => actor.profile.record.displayName), ['Inline contributor', 'Inline contributor']);
+
+  const allLegacyRecord = { ...mixedRecord, contributors: legacyUris };
+  const allLegacy = runGetActivity({ recordJson: allLegacyRecord, serialize: true });
+  assert.equal(allLegacy.status, 0, `${allLegacy.stderr}${allLegacy.stdout}`);
+  const allLegacyActivity = JSON.parse(allLegacy.stdout).activity;
+  assert.deepEqual(allLegacyActivity.record, allLegacyRecord);
+  assert.deepEqual(allLegacyActivity.contributors, [], 'a present source array with only legacy entries projects as an empty array');
+});
+
 test('getActivity serializes exact-version contributor indexed_at null and timestamp strings', () => {
   const exactInformation = {
     ...rows[2], cid: oldCid, record: 'exact-contributor-information',
@@ -370,6 +402,73 @@ function activityRow({ uri, did = authorDid, record, cid, sortTimestamp }) {
   };
 }
 
+test('listActivities continues cursor pages across mixed and all-legacy contributor records', () => {
+  const legacyUris = [
+    'at://did:web:legacy-one.invalid/org.hypercerts.claim.contributorInformation/old',
+    'at://did:web:legacy-two.invalid/org.hypercerts.claim.contributorInformation/older',
+  ];
+  const first = activityRow({
+    uri: `at://${authorDid}/${ACTIVITY}/cursor-first`,
+    cid: 'bafyreiggggggggggggggggggggggggggggggggggggggggggggggggggg',
+    sortTimestamp: '2025-01-01T00:00:00.000000Z',
+    record: { title: 'Cursor first', createdAt: '2025-01-01T00:00:00Z' },
+  });
+  const mixed = activityRow({
+    uri: `at://${authorDid}/${ACTIVITY}/cursor-mixed`,
+    cid: 'bafyreihhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh',
+    sortTimestamp: '2025-01-02T00:00:00.000000Z',
+    record: {
+      title: 'Cursor mixed', createdAt: '2025-01-02T00:00:00Z',
+      contributors: [
+        legacyUris[0],
+        { contributorIdentity: { identity: contributorDid }, contributionWeight: 'kept object' },
+        legacyUris[1],
+      ],
+    },
+  });
+  const allLegacy = activityRow({
+    uri: `at://${authorDid}/${ACTIVITY}/cursor-legacy`,
+    cid: 'bafyreijjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj',
+    sortTimestamp: '2025-01-03T00:00:00.000000Z',
+    record: { title: 'Cursor legacy', createdAt: '2025-01-03T00:00:00Z', contributors: legacyUris },
+  });
+  const profile = (did, displayName) => ({
+    uri: `at://${did}/${PROFILE}/self`, did, collection: PROFILE,
+    cid: 'bafyreikkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk',
+    indexed_at: indexedAt, record: `profile-${did}`,
+    record_json: { $type: PROFILE, displayName, createdAt: indexedAt },
+  });
+  const result = runLuaEndpoint({
+    endpoint: 'listActivities', params: { limit: '1' },
+    queryResults: [
+      [first, mixed], [profile(authorDid, 'Page author')], [],
+      [mixed, allLegacy], [profile(authorDid, 'Page author'), profile(contributorDid, 'Inline contributor')], [],
+      [allLegacy], [profile(authorDid, 'Page author')], [],
+    ],
+    assertions: `
+assert(#result.activities == 1 and result.activities[1].uri == '${first.uri}')
+assert(result.cursor ~= nil, 'the first page must retain its next-page cursor')
+params.cursor = result.cursor
+local secondPage = handle()
+assert(#secondPage.activities == 1 and secondPage.activities[1].uri == '${mixed.uri}')
+assert(secondPage.cursor ~= nil, 'a mixed legacy page must retain its next-page cursor')
+local mixedActivity = secondPage.activities[1]
+assert(#mixedActivity.record.contributors == 3)
+assert(mixedActivity.record.contributors[1] == '${legacyUris[0]}' and mixedActivity.record.contributors[3] == '${legacyUris[1]}')
+assert(#mixedActivity.contributors == 1 and mixedActivity.contributors[1].contributionWeight == 'kept object')
+assert(mixedActivity.contributors[1].actor.did == '${contributorDid}')
+assert(mixedActivity.contributors[1].actor.profile.record.displayName == 'Inline contributor')
+params.cursor = secondPage.cursor
+local thirdPage = handle()
+assert(#thirdPage.activities == 1 and thirdPage.activities[1].uri == '${allLegacy.uri}')
+assert(#thirdPage.activities[1].contributors == 0, 'all-legacy contributors must project densely as empty')
+assert(thirdPage.activities[1].record.contributors[1] == '${legacyUris[0]}')
+assert(thirdPage.cursor == nil and #calls == 9)
+`,
+  });
+  assert.equal(result.status, 0, `${result.stderr}${result.stdout}`);
+});
+
 test('listActivities hydrates actor profiles across multiple bounded lookup batches', () => {
   const contributorDids = Array.from({ length: 501 }, (_, index) => `did:web:contributor-${index}.example`);
   const uri = `at://${authorDid}/${ACTIVITY}/many-contributors`;
@@ -518,6 +617,38 @@ assert(sql:find(' AND ', 1, true), 'search and authors must combine with AND')
   assert.equal(result.status, 0, `${result.stderr}${result.stdout}`);
 });
 
+test('searchActivities skips legacy contributor strings and keeps valid object projections', () => {
+  const legacyUri = 'at://did:web:legacy-search.invalid/org.hypercerts.claim.contributorInformation/old';
+  const row = activityRow({
+    uri: `at://${authorDid}/${ACTIVITY}/search-legacy`,
+    cid: 'bafyreimmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm',
+    record: {
+      title: 'Legacy contributor search', createdAt: indexedAt,
+      contributors: [legacyUri, { contributorIdentity: { identity: contributorDid }, contributionWeight: 'retained' }],
+    },
+  });
+  const authorProfile = {
+    uri: `at://${authorDid}/${PROFILE}/self`, did: authorDid, collection: PROFILE, cid: 'bafyreinnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn',
+    indexed_at: indexedAt, record: 'search-author-profile', record_json: { $type: PROFILE, displayName: 'Search author', createdAt: indexedAt },
+  };
+  const contributorProfile = {
+    uri: `at://${contributorDid}/${PROFILE}/self`, did: contributorDid, collection: PROFILE, cid: 'bafyreieeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee',
+    indexed_at: indexedAt, record: 'search-contributor-profile', record_json: { $type: PROFILE, displayName: 'Search contributor', createdAt: indexedAt },
+  };
+  const result = runLuaEndpoint({
+    endpoint: 'searchActivities', params: { search: 'legacy contributor' },
+    queryResults: [[row], [authorProfile, contributorProfile], []],
+    assertions: `
+local activity = result.activities[1]
+assert(#result.activities == 1 and activity.uri == '${row.uri}')
+assert(activity.record.contributors[1] == '${legacyUri}', 'the raw record must retain the legacy URI string')
+assert(#activity.contributors == 1 and activity.contributors[1].contributionWeight == 'retained')
+assert(activity.contributors[1].actor.profile.record.displayName == 'Search contributor')
+`,
+  });
+  assert.equal(result.status, 0, `${result.stderr}${result.stdout}`);
+});
+
 test('listActivities and searchActivities filter by self organization-record presence', () => {
   for (const { endpoint, params, predicate } of [
     { endpoint: 'listActivities', params: { hasOrganizationRecord: 'true' }, predicate: 'EXISTS' },
diff --git a/api/tests/unit/tooling/collection.test.js b/api/tests/unit/tooling/collection.test.js
index addc194..96692a4 100644
--- a/api/tests/unit/tooling/collection.test.js
+++ b/api/tests/unit/tooling/collection.test.js
@@ -635,8 +635,9 @@ assert(second_page.items[1].record == NULL and second_page.cursor == nil)
 
 test('listCollectionItems preserves source order and weights and resolves only exact supported versions', () => {
   const itemCollectionUri = `at://${did}/${COLLECTION}/parent`;
-  const activityUri = `at://${did}/org.hypercerts.claim.activity/activity-one`;
   const featureDid = 'did:plc:eeeeeeeeeeeeeeeeeeeeeeee';
+  const activityUri = `at://${featureDid}/org.hypercerts.claim.activity/activity-one`;
+  const legacyContributorUri = `at://${did}/org.hypercerts.claim.contributorInformation/legacy`;
   const featureUri = `at://${featureDid}/org.hypercerts.entity.feature/feature-one`;
   const nestedUri = `at://${did}/${COLLECTION}/nested`;
   const activityCid = 'bafyreiaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa';
@@ -658,6 +659,10 @@ test('listCollectionItems preserves source order and weights and resolves only e
     'parent-record': parentRecord,
     'activity-record': {
       $type: 'org.hypercerts.claim.activity', title: 'Resolved activity', createdAt: '2025-01-01T00:00:00Z',
+      contributors: [
+        legacyContributorUri,
+        { contributorIdentity: { identity: featureDid }, contributionWeight: 'retained' },
+      ],
     },
     'feature-record': {
       $type: 'org.hypercerts.entity.feature', type: 'zone', title: 'Resolved feature', createdAt: '2025-01-01T00:00:00Z',
@@ -675,7 +680,7 @@ test('listCollectionItems preserves source order and weights and resolves only e
       indexed_at: '2025-01-02T03:04:05.000Z', record: 'parent-record',
     },
     {
-      uri: activityUri, did, collection: 'org.hypercerts.claim.activity', cid: activityCid,
+      uri: activityUri, did: featureDid, collection: 'org.hypercerts.claim.activity', cid: activityCid,
       indexed_at: '2025-01-02T03:04:05.000Z', record: 'activity-record',
     },
     {
@@ -741,6 +746,10 @@ assert(result.items[1].itemIdentifier.uri == ${JSON.stringify(activityUri)} and
 assert(result.items[1].record.uri == ${JSON.stringify(activityUri)})
 assert(result.items[1].record['$type'] == 'org.hypercerts.claim.getActivity#activityView')
 assert(result.items[1].record.record.title == 'Resolved activity')
+assert(result.items[1].record.record.contributors[1] == '${legacyContributorUri}', 'nested activity source record must retain the legacy URI')
+assert(#result.items[1].record.contributors == 1 and result.items[1].record.contributors[1].contributionWeight == 'retained')
+assert(result.items[1].record.contributors[1].actor.did == '${featureDid}')
+assert(result.items[1].record.contributors[1].actor.profile.record.displayName == 'Feature author')
 assert(result.items[2].record['$type'] == 'org.hypercerts.collection.listCollectionItems#collectionSummaryView')
 assert(result.items[2].record.title == 'Nested summary' and result.items[2].record.shortDescription == 'One level only')
 assert(result.items[3].itemWeight == '1.25')
diff --git a/api/tests/unit/tooling/entity-follow.test.js b/api/tests/unit/tooling/entity-follow.test.js
index 1cb9aeb..218e98f 100644
--- a/api/tests/unit/tooling/entity-follow.test.js
+++ b/api/tests/unit/tooling/entity-follow.test.js
@@ -494,6 +494,7 @@ test('listEntityFollowing returns hydrated ActivityView and CollectionView union
   const activityCollection = 'org.hypercerts.claim.activity';
   const collectionCollection = 'org.hypercerts.collection';
   const activityUri = `at://${activityDid}/${activityCollection}/activity-one`;
+  const legacyContributorUri = `at://${activityDid}/org.hypercerts.claim.contributorInformation/legacy`;
   const collectionUri = `at://${collectionDid}/${collectionCollection}/collection-one`;
   const rawCollection = {
     $type: collectionCollection, title: 'Root collection', createdAt: '2025-01-01T00:00:00Z',
@@ -503,7 +504,10 @@ test('listEntityFollowing returns hydrated ActivityView and CollectionView union
     { uri: `at://${actor}/${entityFollow}/activity-follow`, did: actor, cid: 'bafy-fa', indexed_at: null, record: 'follow-activity', sort_timestamp: '2025-01-03T00:00:00.000000Z', follow_record: { $type: entityFollow, subject: { uri: activityUri }, createdAt: '2025-01-03T00:00:00Z' } },
     { uri: `at://${actor}/${entityFollow}/collection-follow`, did: actor, cid: 'bafy-fc', indexed_at: null, record: 'follow-collection', sort_timestamp: '2025-01-02T00:00:00.000000Z', follow_record: { $type: entityFollow, subject: { uri: collectionUri }, createdAt: '2025-01-02T00:00:00Z' } },
   ];
-  const activity = { uri: activityUri, did: activityDid, cid: 'bafy-activity-latest', indexed_at: null, record: 'activity-record', target_record: { $type: activityCollection, title: 'Resolved activity', createdAt: '2025-01-01T00:00:00Z' } };
+  const activity = { uri: activityUri, did: activityDid, cid: 'bafy-activity-latest', indexed_at: null, record: 'activity-record', target_record: {
+    $type: activityCollection, title: 'Resolved activity', createdAt: '2025-01-01T00:00:00Z',
+    contributors: [legacyContributorUri, { contributorIdentity: { identity: activityDid }, contributionWeight: 'retained' }],
+  } };
   const collection = { uri: collectionUri, did: collectionDid, cid: 'bafy-collection-latest', indexed_at: null, record: 'collection-record', target_record: rawCollection };
   const records = Object.fromEntries([
     ...follows.map(({ record, follow_record }) => [record, follow_record]),
@@ -544,6 +548,9 @@ assert(activity_item.entity['$type'] == 'org.hypercerts.claim.getActivity#activi
 assert(activity_item.uri == FIXTURE.activityUri and activity_item.entity.uri == FIXTURE.activityUri)
 assert(activity_item.entity.cid == 'bafy-activity-latest' and activity_item.entity.indexedAt == NULL_VALUE)
 assert(activity_item.entity.record.title == 'Resolved activity' and activity_item.entity.author.did == FIXTURE.activity.did)
+assert(activity_item.entity.record.contributors[1] == '${legacyContributorUri}', 'followed activity source record must retain the legacy URI')
+assert(#activity_item.entity.contributors == 1 and activity_item.entity.contributors[1].contributionWeight == 'retained')
+assert(activity_item.entity.contributors[1].actor.did == FIXTURE.activity.did)
 assert(activity_item.follow.uri == FIXTURE.follows[1].uri)
 assert(collection_item['$type'] == 'app.certified.graph.listEntityFollowing#entityFollowingItem')
 assert(collection_item.entity['$type'] == 'org.hypercerts.collection.getCollection#collectionView')
diff --git a/docs/openapi.json b/docs/openapi.json
index 54d2e4c..edbb074 100644
--- a/docs/openapi.json
+++ b/docs/openapi.json
@@ -5770,7 +5770,7 @@
           },
           "contributors": {
             "type": "array",
-            "description": "Hydrated contributor projection in the same order and with the same multiplicity as record.contributors; omitted only when the source field is absent.",
+            "description": "Hydrated projection of object entries in record.contributors, preserving their relative order and multiplicity; legacy string entries are skipped and the original record remains unchanged. Omitted only when the source field is absent; if it contains no object entries, this is an empty array.",
             "items": {
               "$ref": "#/components/schemas/org.hypercerts.claim.getActivity.activityContributorView"
             }
diff --git a/docs/sources/lexicons/org.hypercerts.claim.getActivity.json b/docs/sources/lexicons/org.hypercerts.claim.getActivity.json
index d4a6659..59e77b3 100644
--- a/docs/sources/lexicons/org.hypercerts.claim.getActivity.json
+++ b/docs/sources/lexicons/org.hypercerts.claim.getActivity.json
@@ -93,7 +93,7 @@
         },
         "contributors": {
           "type": "array",
-          "description": "Hydrated contributor projection in the same order and with the same multiplicity as record.contributors; omitted only when the source field is absent.",
+          "description": "Hydrated projection of object entries in record.contributors, preserving their relative order and multiplicity; legacy string entries are skipped and the original record remains unchanged. Omitted only when the source field is absent; if it contains no object entries, this is an empty array.",
           "items": {
             "type": "ref",
             "ref": "#activityContributorView"