{
  "handle": "Shard",
  "data_schema": {
    "type": "object",
    "required": [
      "shard_id",
      "partition_index"
    ],
    "properties": {
      "shard_id": {
        "type": "string",
        "description": "Unique identifier for this shard"
      },
      "key": {
        "type": "string",
        "description": "The key used to route to this shard"
      },
      "partition_index": {
        "type": "integer",
        "description": "Which partition this shard belongs to"
      },
      "data": {
        "description": "The shard's contents"
      }
    }
  },
  "mechanism": "The fundamental primitive of distribution. It deterministically partitions a {{resource}}, {{state}}, or {{vector}} into disjoint subsets (Shards) based on a Key (e.g., ID, Hash, Time). Unlike {{decompose}}, which splits complexity, Shard splits volume and load.",
  "gloss": "Deterministic partitioning of state",
  "invariants": [
    "{{conservation}}: Sum(Shards) == Total.",
    "Disjointness: Intersection(Shard_A, Shard_B) == Empty.",
    "Determinism: Key K always routes to Shard S."
  ],
  "parameters": [
    {
      "name": "key_function",
      "type": "Enum",
      "range": "{Hash, Range, Directory}",
      "description": "Partitioning strategy for distributing data across shards"
    },
    {
      "name": "partitions",
      "type": "Integer",
      "range": "[2, 256]",
      "description": "Number of partitions to divide state into"
    }
  ],
  "_meta": {
    "tier": 0,
    "ring": 0,
    "path": [
      "Infrastructure",
      "Data Structures"
    ],
    "supersedes": [
      "sema:Shard#mh:SHA-256:328e51de920cace286a054e313321ff188e34a90d9e5dc8fca1eb2df24baded0",
      "sema:Shard#mh:SHA-256:0c7f0ca5c9169b77bacc5825c072dcb9eef3ff7ceee76a4a2bdbc9ebedaceaa3"
    ]
  },
  "sema_id": "sema:Shard#mh:SHA-256:4d41232416e3d414c714e0892e8559c2180899b4c21c25af29984372220f8704",
  "sema_ref": "Shard#4d41",
  "sema_stub": "4d41",
  "failure_modes": [
    "Hot shard: skewed keys concentrate load on one partition — a consequence of Determinism.",
    "Rebinding on resize: changing the partition count invalidates every routing decision taken under the old count.",
    "Cross-shard operation: spanning shards requires coordination, because Disjointness guarantees no shard holds another's data."
  ],
  "dependencies": {
    "references": {
      "conservation": "sema:Conservation#mh:SHA-256:0b32d007b27a9b5201c46931bdbabd09d08ff9d7b01cf49469f61709989507c2",
      "decompose": "sema:Decompose#mh:SHA-256:69942e7e0dcdc7781144da58c8f09b2e8a17c247be435dadf3325cb0d0bbb22b",
      "resource": "sema:Resource#mh:SHA-256:0e5e5e6735fa9ee49f7e623029d977e435625b8ad05b28f83f962683a0ebb19b",
      "state": "sema:State#mh:SHA-256:4f25e6a16ccd37dc0bc154cccc7055cb504d49daa8b712f372a425eb6c7b8cb2",
      "vector": "sema:Vector#mh:SHA-256:426835100cd1b60d25e87518ba77200fc7b7ec87b917448e09fc03b1087f6993"
    }
  },
  "sema_layer": "Infrastructure",
  "sema_category": "Data Structures",
  "used_by": {
    "references": {
      "ExperienceSharding": "sema:ExperienceSharding#mh:SHA-256:c8a197339886a6bbec3201ead589ad7fd37bbfcde46d6470df59ded8aaa80153",
      "FabricSharding": "sema:FabricSharding#mh:SHA-256:96e1a90c65365b0297a3090f67f2fc88422596a6efb4ecb2ad980c3d365d4216"
    }
  }
}