diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4b9cb13ee..e2834f9df 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,7 +23,6 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Added `aggregations` to `/nodes/_usage/{metric}` requests and responses ([#615](https://github.com/opensearch-project/opensearch-api-specification/pull/615))
 - Added missing `status` to `/_search/template` response ([#702](https://github.com/opensearch-project/opensearch-api-specification/pull/702))
 - Added `_type` to `rank_eval` API specs ([#704](https://github.com/opensearch-project/opensearch-api-specification/pull/704))
-- Added request body to `_search_shards` API specs ([#709](https://github.com/opensearch-project/opensearch-api-specification/pull/709))
 - Added NodeAttributes as additional property in `shard_stores` API specs ([#715](https://github.com/opensearch-project/opensearch-api-specification/pull/715))
 - Added missing `repository` query parameter to `/_cat/snapshots` ([#700](https://github.com/opensearch-project/opensearch-api-specification/pull/700))
 - Added `sm` namespace API specifications ([#701](https://github.com/opensearch-project/opensearch-api-specification/pull/701))
@@ -96,6 +95,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Fixed nodes API schemas ([#761](https://github.com/opensearch-project/opensearch-api-specification/pull/761))
 - Fixed ingest API schemas ([#766](https://github.com/opensearch-project/opensearch-api-specification/pull/766))
 - Fixed CAT API schemas ([#769](https://github.com/opensearch-project/opensearch-api-specification/pull/769))
+- Fixed core API schemas ([#777](https://github.com/opensearch-project/opensearch-api-specification/pull/777))
 
 ### Changed
 - Changed `tasks._common:TaskInfo` and `tasks._common:TaskGroup` to be composed of a `tasks._common:TaskInfoBase` ([#683](https://github.com/opensearch-project/opensearch-api-specification/pull/683))
diff --git a/spec/namespaces/_core.yaml b/spec/namespaces/_core.yaml
index ee5ca443e..3d24fb9b2 100644
--- a/spec/namespaces/_core.yaml
+++ b/spec/namespaces/_core.yaml
@@ -455,6 +455,7 @@ paths:
         - $ref: '#/components/parameters/reindex::query.max_docs'
         - $ref: '#/components/parameters/reindex::query.refresh'
         - $ref: '#/components/parameters/reindex::query.requests_per_second'
+        - $ref: '#/components/parameters/reindex::query.require_alias'
         - $ref: '#/components/parameters/reindex::query.scroll'
         - $ref: '#/components/parameters/reindex::query.slices'
         - $ref: '#/components/parameters/reindex::query.timeout'
@@ -1028,8 +1029,6 @@ paths:
         - $ref: '#/components/parameters/search_shards::query.local'
         - $ref: '#/components/parameters/search_shards::query.preference'
         - $ref: '#/components/parameters/search_shards::query.routing'
-      requestBody:
-        $ref: '#/components/requestBodies/search_shards'
       responses:
         '200':
           $ref: '#/components/responses/search_shards@200'
@@ -1047,8 +1046,6 @@ paths:
         - $ref: '#/components/parameters/search_shards::query.local'
         - $ref: '#/components/parameters/search_shards::query.preference'
         - $ref: '#/components/parameters/search_shards::query.routing'
-      requestBody:
-        $ref: '#/components/requestBodies/search_shards'
       responses:
         '200':
           $ref: '#/components/responses/search_shards@200'
@@ -2011,8 +2008,6 @@ paths:
         - $ref: '#/components/parameters/search_shards::query.local'
         - $ref: '#/components/parameters/search_shards::query.preference'
         - $ref: '#/components/parameters/search_shards::query.routing'
-      requestBody:
-        $ref: '#/components/requestBodies/search_shards'
       responses:
         '200':
           $ref: '#/components/responses/search_shards@200'
@@ -2031,8 +2026,6 @@ paths:
         - $ref: '#/components/parameters/search_shards::query.local'
         - $ref: '#/components/parameters/search_shards::query.preference'
         - $ref: '#/components/parameters/search_shards::query.routing'
-      requestBody:
-        $ref: '#/components/requestBodies/search_shards'
       responses:
         '200':
           $ref: '#/components/responses/search_shards@200'
@@ -2703,46 +2696,6 @@ components:
                 type: string
             description: The search definition template and its parameters.
       required: true
-    search_shards:
-      content:
-        application/json:
-          schema:
-            type: object
-            properties:
-              query:
-                description: Defines the search query to filter shards. Supports any query that is valid for the `_search` endpoint.
-                type: object
-                additionalProperties:
-                  type: object
-              indices_boost:
-                description: Allows increasing the relevance of specific indexes in the search.
-                type: object
-                additionalProperties:
-                  type: number
-              allow_partial_search_results:
-                description: Indicates whether partial search results are allowed if some shards are unavailable.
-                type: boolean
-              _source:
-                description: Specifies which fields to include in the `_source` response or excludes specific fields.
-                oneOf:
-                  - type: boolean
-                  - type: array
-                    items:
-                      type: string
-              from:
-                description: The starting offset (default 0) for paginated results.
-                type: integer
-              size:
-                description: The maximum number of results to return (default 10).
-                type: integer
-              sort:
-                description: A list of fields and directions for sorting the results.
-                type: array
-                items:
-                  type: object
-                  additionalProperties:
-                    type: string
-            description: Defines the parameters that can be used in the `search_shards` endpoint request. See documentation for supported query syntax.
     termvectors:
       content:
         application/json:
@@ -2921,7 +2874,7 @@ components:
               pit_id:
                 type: string
               _shards:
-                $ref: '../schemas/_core._common.yaml#/components/schemas/ShardStatistics'
+                $ref: '../schemas/_common.yaml#/components/schemas/ShardStatistics'
               creation_time:
                 type: integer
                 format: int64
@@ -2944,7 +2897,7 @@ components:
               pits:
                 type: array
                 items:
-                  $ref: '../schemas/_core._common.yaml#/components/schemas/PitsDetailsDeleteAll'
+                  $ref: '../schemas/_core.pit.yaml#/components/schemas/DeletedPit'
     delete_by_query@200:
       content:
         application/json:
@@ -2969,7 +2922,7 @@ components:
               pits:
                 type: array
                 items:
-                  $ref: '../schemas/_core._common.yaml#/components/schemas/DeletedPit'
+                  $ref: '../schemas/_core.pit.yaml#/components/schemas/DeletedPit'
     delete_script@200:
       content:
         application/json:
@@ -3045,7 +2998,7 @@ components:
               pits:
                 type: array
                 items:
-                  $ref: '../schemas/_core._common.yaml#/components/schemas/PitDetail'
+                  $ref: '../schemas/_core.pit.yaml#/components/schemas/PitDetail'
     get_script@200:
       content:
         application/json:
@@ -3191,8 +3144,7 @@ components:
                   $ref: '../schemas/_core.rank_eval.yaml#/components/schemas/RankEvalMetricDetail'
               failures:
                 type: object
-                additionalProperties:
-                  type: object
+                additionalProperties: true
             required:
               - details
               - failures
@@ -3227,8 +3179,7 @@ components:
             properties:
               template_output:
                 type: object
-                additionalProperties:
-                  type: object
+                additionalProperties: true
             required:
               - template_output
     scripts_painless_execute@200:
@@ -3953,10 +3904,7 @@ components:
       description: Set to `true` or `false` to return the `_source` field or not, or a list of fields to return.
       style: form
       schema:
-        type: array
-        items:
-          type: string
-        description: Set to `true` or `false` to return the `_source` field or not, or a list of fields to return.
+        $ref: '../schemas/_core.search.yaml#/components/schemas/SourceConfigParam'
       explode: true
     delete_by_query::query._source_excludes:
       name: _source_excludes
@@ -5341,6 +5289,11 @@ components:
         format: float
         default: 0
       style: form
+    reindex::query.require_alias:
+      in: query
+      name: require_alias
+      schema:
+        type: boolean
     reindex::query.scroll:
       in: query
       name: scroll
@@ -6295,10 +6248,7 @@ components:
       description: Set to `true` or `false` to return the `_source` field or not, or a list of fields to return.
       style: form
       schema:
-        type: array
-        items:
-          type: string
-        description: Set to `true` or `false` to return the `_source` field or not, or a list of fields to return.
+        $ref: '../schemas/_core.search.yaml#/components/schemas/SourceConfigParam'
       explode: true
     update_by_query::query._source_excludes:
       name: _source_excludes
diff --git a/spec/schemas/_common.yaml b/spec/schemas/_common.yaml
index 6491758db..9f9a838eb 100644
--- a/spec/schemas/_common.yaml
+++ b/spec/schemas/_common.yaml
@@ -444,10 +444,13 @@ components:
     VersionString:
       type: string
     SearchType:
-      type: string
-      enum:
-        - dfs_query_then_fetch
-        - query_then_fetch
+      oneOf:
+        - type: string
+          const: dfs_query_then_fetch
+          description: Documents are scored using global term and document frequencies across all shards. This is usually slower but more accurate.
+        - type: string
+          const: query_then_fetch
+          description: Documents are scored using local term and document frequencies for the shard. This is usually faster but less accurate.
     SuggestMode:
       type: string
       enum:
@@ -752,7 +755,8 @@ components:
         field:
           $ref: '#/components/schemas/Field'
         id:
-          $ref: '#/components/schemas/Id'
+          type: integer
+          format: int32
         max:
           type: integer
           format: int32
@@ -1573,8 +1577,11 @@ components:
     Slices:
       description: The slice configuration used to parallelize a process.
       oneOf:
-        - type: number
-        - $ref: '#/components/schemas/SlicesCalculation'
+        - title: count
+          type: integer
+          format: int32
+        - title: calculation
+          $ref: '#/components/schemas/SlicesCalculation'
     SlicesCalculation:
       type: string
       enum:
@@ -2218,7 +2225,8 @@ components:
         node:
           $ref: '#/components/schemas/NodeName'
         shard:
-          type: number
+          type: integer
+          format: int32
         index:
           $ref: '#/components/schemas/IndexName'
         allocation_id:
@@ -2235,20 +2243,11 @@ components:
           oneOf:
             - $ref: '#/components/schemas/NodeId'
             - type: 'null'
-        relocation_failure_info:
-          $ref: '#/components/schemas/RelocationFailureInfo'
       required:
         - index
         - primary
         - shard
         - state
-    RelocationFailureInfo:
-      type: object
-      properties:
-        failed_attempts:
-          type: number
-      required:
-        - failed_attempts
     OpenSearchVersionInfo:
       type: object
       properties:
diff --git a/spec/schemas/_core._common.yaml b/spec/schemas/_core._common.yaml
deleted file mode 100644
index 4b1690c7e..000000000
--- a/spec/schemas/_core._common.yaml
+++ /dev/null
@@ -1,48 +0,0 @@
-openapi: 3.1.0
-info:
-  title: Schemas of `_core._common` Category
-  description: Schemas of `_core._common` category.
-  version: 1.0.0
-paths: {}
-components:
-  schemas:
-    DeletedPit:
-      type: object
-      properties:
-        successful:
-          type: boolean
-        pit_id:
-          type: string
-    PitsDetailsDeleteAll:
-      type: object
-      properties:
-        successful:
-          type: boolean
-        pit_id:
-          type: string
-    PitDetail:
-      type: object
-      properties:
-        pit_id:
-          type: string
-        creation_time:
-          type: integer
-          format: int64
-        keep_alive:
-          type: integer
-          format: int64
-    ShardStatistics:
-      type: object
-      properties:
-        total:
-          type: integer
-          format: int32
-        successful:
-          type: integer
-          format: int32
-        skipped:
-          type: integer
-          format: int32
-        failed:
-          type: integer
-          format: int32
diff --git a/spec/schemas/_core.field_caps.yaml b/spec/schemas/_core.field_caps.yaml
index 3a0d4a589..c046654e5 100644
--- a/spec/schemas/_core.field_caps.yaml
+++ b/spec/schemas/_core.field_caps.yaml
@@ -15,7 +15,11 @@ components:
         indices:
           $ref: '_common.yaml#/components/schemas/Indices'
         meta:
-          $ref: '_common.yaml#/components/schemas/Metadata'
+          type: object
+          additionalProperties:
+            type: array
+            items:
+              type: string
         non_aggregatable_indices:
           $ref: '_common.yaml#/components/schemas/Indices'
         non_searchable_indices:
diff --git a/spec/schemas/_core.mtermvectors.yaml b/spec/schemas/_core.mtermvectors.yaml
index 503dccafb..7b8e36a65 100644
--- a/spec/schemas/_core.mtermvectors.yaml
+++ b/spec/schemas/_core.mtermvectors.yaml
@@ -15,7 +15,6 @@ components:
           $ref: '_common.yaml#/components/schemas/IndexName'
         doc:
           description: An artificial document for which you want to retrieve term vectors.
-          type: object
         fields:
           $ref: '_common.yaml#/components/schemas/Fields'
         field_statistics:
@@ -53,7 +52,8 @@ components:
         _version:
           $ref: '_common.yaml#/components/schemas/VersionNumber'
         took:
-          type: number
+          type: integer
+          format: int64
         found:
           type: boolean
         term_vectors:
diff --git a/spec/schemas/_core.pit.yaml b/spec/schemas/_core.pit.yaml
new file mode 100644
index 000000000..883ecb0d8
--- /dev/null
+++ b/spec/schemas/_core.pit.yaml
@@ -0,0 +1,26 @@
+openapi: 3.1.0
+info:
+  title: Schemas of `_core.pit` Category
+  description: Schemas of `_core.pit` category.
+  version: 1.0.0
+paths: {}
+components:
+  schemas:
+    DeletedPit:
+      type: object
+      properties:
+        successful:
+          type: boolean
+        pit_id:
+          type: string
+    PitDetail:
+      type: object
+      properties:
+        pit_id:
+          type: string
+        creation_time:
+          type: integer
+          format: int64
+        keep_alive:
+          type: integer
+          format: int64
diff --git a/spec/schemas/_core.rank_eval.yaml b/spec/schemas/_core.rank_eval.yaml
index 436d271ea..3628482da 100644
--- a/spec/schemas/_core.rank_eval.yaml
+++ b/spec/schemas/_core.rank_eval.yaml
@@ -23,8 +23,7 @@ components:
         params:
           description: The search template parameters. 
           type: object
-          additionalProperties:
-            type: object
+          additionalProperties: true
       required:
         - id
         - ratings
@@ -34,7 +33,8 @@ components:
         query:
           $ref: '_common.query_dsl.yaml#/components/schemas/QueryContainer'
         size:
-          type: number
+          type: integer
+          format: int32
       required:
         - query
     DocumentRating:
@@ -46,7 +46,8 @@ components:
           $ref: '_common.yaml#/components/schemas/IndexName'
         rating:
           description: The document's relevance with regard to the specified search request.
-          type: number
+          type: integer
+          format: int32
       required:
         - _id
         - _index
@@ -79,13 +80,15 @@ components:
           properties:
             relevant_rating_threshold:
               description: Sets the rating threshold above which documents are considered to be relevant.
-              type: number
+              type: integer
+              format: int32
     RankEvalMetricBase:
       type: object
       properties:
         k:
           description: Sets the maximum number of documents retrieved per query. This value replaces the `size` parameter in the query.
-          type: number
+          type: integer
+          format: int32
     RankEvalMetricRecall:
       allOf:
         - $ref: '#/components/schemas/RankEvalMetricRatingThreshold'
@@ -109,7 +112,8 @@ components:
           properties:
             maximum_relevance:
               description: The highest relevance grade used in user-supplied relevance judgments.
-              type: number
+              type: integer
+              format: int32
           required:
             - maximum_relevance
     RankEvalMetricDetail:
@@ -118,6 +122,7 @@ components:
         metric_score:
           description: The `metric_score`, found in the `metric_details` section, shows the contribution of this query to the global quality metric score.
           type: number
+          format: double
         unrated_docs:
           description: The `unrated_docs` section contains an `_index` and `_id` entry for each document that didn't have a `ratings` value. This can be used to ask the user to supply ratings for these documents.
           type: array
@@ -133,8 +138,7 @@ components:
           type: object
           additionalProperties:
             type: object
-            additionalProperties:
-              type: number
+            additionalProperties: true
       required:
         - hits
         - metric_details
@@ -156,7 +160,8 @@ components:
         hit:
           $ref: '#/components/schemas/RankEvalHit'
         rating:
-          type: ['null', number, string]
+          type: integer
+          format: int32
       required:
         - hit
     RankEvalHit:
@@ -168,6 +173,7 @@ components:
           $ref: '_common.yaml#/components/schemas/IndexName'
         _score:
           type: number
+          format: double
         _type:
           $ref: '_common.yaml#/components/schemas/Type'
       required:
diff --git a/spec/schemas/_core.reindex.yaml b/spec/schemas/_core.reindex.yaml
index 34fdbe13e..2ceef38e0 100644
--- a/spec/schemas/_core.reindex.yaml
+++ b/spec/schemas/_core.reindex.yaml
@@ -35,7 +35,8 @@ components:
           description: |-
             The number of documents to index per batch.
             Use the `size` setting when indexing from a remote cluster. This ensures that batches fit in the on-heap buffer. The buffer defaults to a maximum size of `100MB`.
-          type: number
+          type: integer
+          format: int32
         slice:
           $ref: '_common.yaml#/components/schemas/SlicedScroll'
         sort:
diff --git a/spec/schemas/_core.reindex_rethrottle.yaml b/spec/schemas/_core.reindex_rethrottle.yaml
index bc5ce3a8a..0f0b0d1e1 100644
--- a/spec/schemas/_core.reindex_rethrottle.yaml
+++ b/spec/schemas/_core.reindex_rethrottle.yaml
@@ -29,7 +29,8 @@ components:
         description:
           type: string
         id:
-          type: number
+          type: integer
+          format: int64
         node:
           $ref: '_common.yaml#/components/schemas/Name'
         resource_stats:
@@ -60,19 +61,24 @@ components:
       properties:
         batches:
           description: The number of scroll responses shown by the reindex.
-          type: number
+          type: integer
+          format: int64
         created:
           description: The number of documents that were successfully created.
-          type: number
+          type: integer
+          format: int64
         deleted:
           description: The number of documents that were successfully deleted.
-          type: number
+          type: integer
+          format: int64
         noops:
           description: The number of documents that were ignored because the script used for the reindex operation returned a `noop` value for `ctx.op`.
-          type: number
+          type: integer
+          format: int64
         requests_per_second:
           description: The number of successful requests per second during the reindex operation.
           type: number
+          format: float
         retries:
           $ref: '_common.yaml#/components/schemas/Retries'
         throttled:
@@ -85,13 +91,16 @@ components:
           $ref: '_common.yaml#/components/schemas/DurationValueUnitMillis'
         total:
           description: The number of documents that were successfully processed.
-          type: number
+          type: integer
+          format: int64
         updated:
           description: The number of documents that were successfully updated.
-          type: number
+          type: integer
+          format: int64
         version_conflicts:
           description: The number of version conflicts that reindex hits.
-          type: number
+          type: integer
+          format: int64
       required:
         - batches
         - created
diff --git a/spec/schemas/_core.search.yaml b/spec/schemas/_core.search.yaml
index 1dbef6a1d..5183f28c8 100644
--- a/spec/schemas/_core.search.yaml
+++ b/spec/schemas/_core.search.yaml
@@ -651,8 +651,10 @@ components:
         Defines how to fetch a source. Fetching can be disabled entirely, or the source can be filtered.
         Use this setting with the `_source_includes` and `_source_excludes` parameters.
       oneOf:
-        - type: boolean
-        - $ref: '_common.yaml#/components/schemas/Fields'
+        - title: fetch
+          type: boolean
+        - title: fields
+          $ref: '_common.yaml#/components/schemas/Fields'
     InnerHits:
       type: object
       properties:
diff --git a/spec/schemas/_core.termvectors.yaml b/spec/schemas/_core.termvectors.yaml
index 1b6d0a8c8..24d73fdfd 100644
--- a/spec/schemas/_core.termvectors.yaml
+++ b/spec/schemas/_core.termvectors.yaml
@@ -13,33 +13,40 @@ components:
           description: |-
             Ignores words that appear in more than the specified number of documents.
             Default is `unbounded`.
-          type: number
+          type: integer
+          format: int32
         max_num_terms:
           description: The maximum number of terms that should be returned per field.
-          type: number
+          type: integer
+          format: int32
         max_term_freq:
           description: |-
             Ignore words with more than this frequency in the source doc.
             Default is `unbounded`.
-          type: number
+          type: integer
+          format: int32
         max_word_length:
           description: |-
             The maximum word length.
             Words longer than this value will be ignored.
             Default is `unbounded`.
-          type: number
+          type: integer
+          format: int32
         min_doc_freq:
           description: Ignore terms which do not occur in at least this many docs.
-          type: number
+          type: integer
+          format: int32
         min_term_freq:
           description: Ignore words with less than this frequency in the source doc.
-          type: number
+          type: integer
+          format: int32
         min_word_length:
           description: |-
             The minimum word length.
             Words shorter than this value will be ignored.
             Default is 0.
-          type: number
+          type: integer
+          format: int32
     TermVector:
       type: object
       properties:
@@ -50,17 +57,19 @@ components:
           additionalProperties:
             $ref: '#/components/schemas/Term'
       required:
-        - field_statistics
         - terms
     FieldStatistics:
       type: object
       properties:
         doc_count:
-          type: number
+          type: integer
+          format: int32
         sum_doc_freq:
-          type: number
+          type: integer
+          format: int64
         sum_ttf:
-          type: number
+          type: integer
+          format: int64
       required:
         - doc_count
         - sum_doc_freq
@@ -69,29 +78,36 @@ components:
       type: object
       properties:
         doc_freq:
-          type: number
+          type: integer
+          format: int32
         score:
           type: number
+          format: double
         term_freq:
-          type: number
+          type: integer
+          format: int32
         tokens:
           type: array
           items:
             $ref: '#/components/schemas/Token'
         ttf:
-          type: number
+          type: integer
+          format: int32
       required:
         - term_freq
     Token:
       type: object
       properties:
         end_offset:
-          type: number
+          type: integer
+          format: int32
         payload:
           type: string
         position:
-          type: number
+          type: integer
+          format: int32
         start_offset:
-          type: number
+          type: integer
+          format: int32
       required:
         - position
diff --git a/tests/default/_core/search_shards.yaml b/tests/default/_core/search_shards.yaml
index 318a6d234..a592208aa 100644
--- a/tests/default/_core/search_shards.yaml
+++ b/tests/default/_core/search_shards.yaml
@@ -22,16 +22,5 @@ chapters:
   - synopsis: Verify the distribution of shards for the index.
     path: /_search_shards
     method: GET
-    response:
-      status: 200
-  
-  - synopsis: Check routing behavior based on search criteria.
-    path: /_search_shards
-    method: POST
-    request:
-      payload:
-        query:
-          match:
-            title: To Kill a Mockingbird
     response:
       status: 200
\ No newline at end of file
diff --git a/tests/default/indices/search_shards.yaml b/tests/default/indices/search_shards.yaml
index bcb755962..01472073a 100644
--- a/tests/default/indices/search_shards.yaml
+++ b/tests/default/indices/search_shards.yaml
@@ -24,18 +24,5 @@ chapters:
     parameters:
       index: movies
     method: GET
-    response:
-      status: 200
-  
-  - synopsis: Check routing behavior based on search criteria.
-    path: /{index}/_search_shards
-    parameters:
-      index: movies
-    method: POST
-    request:
-      payload:
-        query:
-          match:
-            title: To Kill a Mockingbird
     response:
       status: 200
\ No newline at end of file