{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$defs": {
    "primitives": {
      // All supported primitive data types
      "type": "string",
      "enum": ["string", "integer", "float", "boolean", "json"]
    },
    "value_schema": {
      // Represents a value schema (e.g. function input parameter)
      "type": "object",
      "properties": {
        "type": {
          "$ref": "#/$defs/primitives"
        }
      },
      "required": ["type"],
      "additionalProperties": false,
      "if": {
        "properties": {
          "type": {
            "const": "string"
          }
        }
      },
      "then": {
        // String values can optionally be constrained to a known list
        "properties": {
          "enum": {
            "type": "array",
            "items": {
              "type": "string"
            }
          }
        }
      }
    }
  },
  "type": "object",
  "properties": {
    "$schema": {
      // Explicitly allow JSON-Schema to be referenced (due to additionalProperties: false)
      "type": "string",
      "format": "uri"
    },
    "name": {
      "type": "string",
      "description": "The tool name"
    },
    "description": {
      "type": "string",
      "description": "A human-readable description of the tool and when to use it"
    },
    "version": {
      "type": "string",
      "pattern": "^[a-f0-9]{7,40}$", // SHA version pattern (7-40 hexadecimal characters)
      "description": "An identifier for this version of the tool"
    },
    "input": {
      "type": "object",
      "properties": {
        "parameters": {
          "type": "array",
          "minItems": 1,
          "items": {
            "type": "object",
            "properties": {
              "name": {
                "description": "The human-readable name of this parameter.",
                "type": "string"
              },
              "required": {
                "description": "Whether this parameter is required (true) or optional (false).",
                "type": "boolean"
              },
              "description": {
                "description": "A descriptive, human-readable explanation of the parameter.",
                "type": "string"
              },
              "schema": {
                "$ref": "#/$defs/value_schema"
              },
              "inferrable": {
                "type": "boolean",
                "description": "Whether a value for this parameter can be inferred by a model. Defaults to `true`.",
                "default": true
              }
            },
            "required": ["name", "required", "schema"],
            "additionalProperties": false
          }
        }
      },
      "required": ["parameters"],
      "additionalProperties": false
    },
    "output": {
      "type": "object",
      "properties": {
        "available_modes": {
          "type": "array",
          "minItems": 1,
          "items": {
            "type": "string",
            "enum": ["value", "error", "null", "artifact", "requires_authorization"]
          }
        },
        "value": {
          "type": "object",
          "properties": {
            "description": {
              "type": "string"
            },
            "schema": {
              "$ref": "#/$defs/value_schema"
            }
          },
          "required": ["schema"],
          "additionalProperties": false
        }
      },
      "required": ["available_modes"],
      "additionalProperties": false
    },
    "requirements": {
      "type": "object",
      "properties": {
        "authorization": {
          "oneOf": [
            {
              "type": "string",
              "enum": ["none", "token"]
            },
            {
              "type": "object",
              "properties": {
                "oauth2": {
                  "type": "object",
                  "properties": {
                    "url": {
                      "type": "string",
                      "format": "uri"
                    },
                    "scope": {
                      "type": "string"
                    }
                  },
                  "required": ["url"],
                  "additionalProperties": false
                }
              },
              "required": ["oauth2"],
              "additionalProperties": false
            }
          ]
        }
      }
    }
  },
  "required": ["name", "version", "input", "output"],
  "additionalProperties": false
}