{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://leji.org/schemas/v1.0/context-changelog.schema.json",
  "title": "Leji context changelog",
  "description": "Append-only machine-readable record of context layer changes.",
  "type": "object",
  "required": [
    "schemaVersion",
    "entries"
  ],
  "additionalProperties": false,
  "properties": {
    "$schema": {
      "description": "Optional pointer to this schema, for editor validation and tooling.",
      "type": "string"
    },
    "schemaVersion": {
      "description": "The Leji spec line this artifact was written against, e.g. \"1.0\".",
      "type": "string",
      "pattern": "^\\d+\\.\\d+$"
    },
    "entries": {
      "description": "Context layer changes. Canonical order is derived by sorting on (date, id) ascending; array position is not significant. New entries may appear anywhere; the oldest may be compacted with a compaction entry.",
      "type": "array",
      "items": {
        "type": "object",
        "required": [
          "id",
          "date",
          "type",
          "summary",
          "paths"
        ],
        "additionalProperties": false,
        "properties": {
          "id": {
            "description": "Stable identifier for this change entry, unique within the changelog.",
            "type": "string",
            "pattern": "^[a-z0-9]+(-[a-z0-9]+)*$"
          },
          "date": {
            "description": "ISO 8601 in UTC: a calendar date YYYY-MM-DD (ordered as start of day) or a full timestamp ending in Z, e.g. 2026-06-13T15:04:05Z. Offsets and zoneless times are not allowed, so lexical order is chronological.",
            "type": "string",
            "pattern": "^\\d{4}-\\d{2}-\\d{2}(T\\d{2}:\\d{2}:\\d{2}(\\.\\d{1,9})?Z)?$"
          },
          "type": {
            "description": "The kind of change.",
            "enum": [
              "added",
              "changed",
              "deprecated",
              "removed",
              "fixed",
              "decision",
              "governance",
              "compaction"
            ]
          },
          "summary": {
            "description": "One-line description of what changed.",
            "type": "string",
            "minLength": 1
          },
          "paths": {
            "description": "Repository-root-relative paths the change affected.",
            "type": "array",
            "items": {
              "type": "string",
              "pattern": "^(?!/)(?!\\./)(?!.*(^|/)\\.\\.(/|$))(?!.*\\\\).+$"
            }
          },
          "categories": {
            "description": "Content categories the change touched.",
            "type": "array",
            "items": {
              "enum": [
                "domain",
                "system",
                "practice",
                "governance",
                "decisions"
              ]
            }
          },
          "decisionRefs": {
            "description": "Ids of decision records related to this change.",
            "type": "array",
            "items": {
              "type": "string"
            }
          },
          "proposedBy": {
            "type": "string",
            "description": "Human or agent that proposed the change."
          },
          "approvedBy": {
            "type": "string",
            "description": "Human who approved the change."
          },
          "breaking": {
            "description": "Whether the change breaks consumers of the context layer.",
            "type": "boolean"
          },
          "compacted": {
            "type": "object",
            "description": "Required on compaction entries: what the compaction removed from the oldest end.",
            "required": [
              "entries",
              "firstId",
              "lastId"
            ],
            "additionalProperties": false,
            "properties": {
              "entries": {
                "description": "How many entries this compaction removed from the oldest end.",
                "type": "integer",
                "minimum": 1
              },
              "firstId": {
                "description": "Id of the oldest entry removed by this compaction.",
                "type": "string",
                "pattern": "^[a-z0-9]+(-[a-z0-9]+)*$"
              },
              "lastId": {
                "description": "Id of the newest entry removed by this compaction.",
                "type": "string",
                "pattern": "^[a-z0-9]+(-[a-z0-9]+)*$"
              }
            }
          }
        },
        "if": {
          "properties": {
            "type": {
              "const": "compaction"
            }
          },
          "required": [
            "type"
          ]
        },
        "then": {
          "required": [
            "compacted"
          ]
        }
      }
    }
  }
}