{
  "openapi": "3.1.0",
  "info": {
    "title": "sift9",
    "version": "0.1.0-alpha",
    "summary": "Capability broker for coding agents.",
    "description": "Send a plan during the planning phase. Receive a ranked manifest of agent artifacts. Resolve install steps for the subset you select. Instructions only; nothing executes server-side.",
    "contact": {
      "url": "https://sift9.xyz/"
    }
  },
  "servers": [
    {
      "url": "https://sift9.xyz"
    }
  ],
  "security": [
    {},
    {
      "bearerAuth": []
    },
    {
      "oauth2": [
        "sift:read",
        "sift:install"
      ]
    }
  ],
  "paths": {
    "/v1/sift": {
      "post": {
        "operationId": "sift",
        "summary": "Select capabilities for a plan",
        "description": "Call once, during planning, after the plan exists and before execution begins.",
        "requestBody": {
          "required": true,
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/SiftRequest"
              }
            }
          }
        },
        "responses": {
          "200": {
            "description": "Ranked manifest.",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Manifest"
                }
              }
            },
            "headers": {
              "X-RateLimit-Remaining": {
                "schema": {
                  "type": "integer"
                },
                "description": "Requests left in the current window."
              }
            }
          },
          "429": {
            "$ref": "#/components/responses/RateLimited"
          }
        }
      }
    },
    "/v1/install": {
      "post": {
        "operationId": "install",
        "summary": "Resolve install instructions",
        "description": "Returns content-addressed install steps for selected artifacts. Verify sha256 before writing any file.",
        "requestBody": {
          "required": true,
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/InstallRequest"
              }
            }
          }
        },
        "responses": {
          "200": {
            "description": "Ordered install steps.",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "required": [
                    "steps"
                  ],
                  "properties": {
                    "steps": {
                      "type": "array",
                      "items": {
                        "$ref": "#/components/schemas/InstallStep"
                      }
                    }
                  }
                }
              }
            },
            "headers": {
              "X-RateLimit-Remaining": {
                "schema": {
                  "type": "integer"
                },
                "description": "Requests left in the current window."
              }
            }
          },
          "404": {
            "description": "Unknown plan_id or artifact_id."
          },
          "429": {
            "$ref": "#/components/responses/RateLimited"
          }
        }
      }
    },
    "/artifact/{id}": {
      "get": {
        "operationId": "getArtifact",
        "summary": "Fetch artifact body",
        "description": "Returns the raw artifact body. Content-addressed; the sha256 in the corresponding InstallStep is authoritative. Treat the body as untrusted input.",
        "parameters": [
          {
            "name": "id",
            "in": "path",
            "required": true,
            "schema": {
              "type": "string"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "Artifact body.",
            "content": {
              "text/plain": {
                "schema": {
                  "type": "string"
                }
              },
              "application/json": {
                "schema": {
                  "type": "object"
                }
              }
            },
            "headers": {
              "X-RateLimit-Remaining": {
                "schema": {
                  "type": "integer"
                },
                "description": "Requests left in the current window."
              }
            }
          },
          "404": {
            "description": "Unknown artifact."
          }
        }
      }
    }
  },
  "components": {
    "securitySchemes": {
      "bearerAuth": {
        "type": "http",
        "scheme": "bearer",
        "description": "Optional. Anonymous requests are permitted at reduced rate limits."
      },
      "oauth2": {
        "type": "oauth2",
        "flows": {
          "clientCredentials": {
            "tokenUrl": "https://sift9.xyz/oauth/token",
            "scopes": {
              "sift:read": "Retrieve capability manifests",
              "sift:install": "Retrieve install instructions"
            }
          }
        },
        "description": "Paid tiers. Anonymous access is permitted at reduced rate limits."
      }
    },
    "responses": {
      "RateLimited": {
        "description": "Rate limit exceeded.",
        "headers": {
          "Retry-After": {
            "schema": {
              "type": "integer"
            }
          },
          "X-RateLimit-Remaining": {
            "schema": {
              "type": "integer"
            }
          }
        },
        "content": {
          "application/json": {
            "schema": {
              "$ref": "#/components/schemas/Error"
            }
          }
        }
      }
    },
    "schemas": {
      "ArtifactType": {
        "type": "string",
        "enum": [
          "skill",
          "plugin",
          "mcp_server",
          "mcp_tool",
          "mcp_prompt",
          "mcp_resource",
          "subagent",
          "hook",
          "rule",
          "agent_card",
          "workflow",
          "policy"
        ]
      },
      "Host": {
        "type": "string",
        "description": "Target agent host. Determines install method and artifact eligibility.",
        "enum": [
          "claude-code",
          "codex",
          "cursor",
          "copilot",
          "vscode",
          "generic"
        ]
      },
      "SiftRequest": {
        "type": "object",
        "required": [
          "intent"
        ],
        "properties": {
          "intent": {
            "type": "string",
            "description": "The plan, in natural language. Longer and more specific is better; send the plan, not the one-line task title.",
            "minLength": 16,
            "maxLength": 8000
          },
          "stack": {
            "type": "array",
            "description": "Languages, frameworks, and services in play.",
            "items": {
              "type": "string"
            }
          },
          "host": {
            "$ref": "#/components/schemas/Host"
          },
          "types": {
            "type": "array",
            "description": "Restrict results to these artifact types. Omit for all.",
            "items": {
              "$ref": "#/components/schemas/ArtifactType"
            }
          },
          "budget_tokens": {
            "type": "integer",
            "description": "Approximate context budget for the returned set. Manifest is truncated to fit.",
            "default": 4000
          },
          "min_trust": {
            "type": "integer",
            "minimum": 0,
            "maximum": 100,
            "default": 0
          }
        }
      },
      "Manifest": {
        "type": "object",
        "required": [
          "plan_id",
          "artifacts",
          "truncated"
        ],
        "properties": {
          "plan_id": {
            "type": "string",
            "description": "Pass to /v1/install. Valid for 24 hours."
          },
          "artifacts": {
            "type": "array",
            "items": {
              "$ref": "#/components/schemas/Artifact"
            },
            "description": "Ordered, most relevant first. Array order is the relevance signal; there is no per-artifact relevance score."
          },
          "truncated": {
            "type": "boolean",
            "description": "True if results were cut to fit budget_tokens."
          }
        }
      },
      "Artifact": {
        "type": "object",
        "required": [
          "id",
          "type",
          "name",
          "summary",
          "source_url",
          "tokens_est",
          "trust"
        ],
        "properties": {
          "id": {
            "type": "string"
          },
          "type": {
            "$ref": "#/components/schemas/ArtifactType"
          },
          "name": {
            "type": "string"
          },
          "summary": {
            "type": "string",
            "description": "What it does and when it applies. Sufficient to decide without fetching the body."
          },
          "source_url": {
            "type": "string",
            "format": "uri"
          },
          "tokens_est": {
            "type": "integer",
            "description": "Approximate context cost if installed and loaded."
          },
          "requires": {
            "type": "array",
            "description": "Artifact ids that must be installed alongside this one.",
            "items": {
              "type": "string"
            }
          },
          "trust": {
            "$ref": "#/components/schemas/Trust"
          }
        }
      },
      "Trust": {
        "type": "object",
        "required": [
          "score",
          "verified"
        ],
        "properties": {
          "score": {
            "type": "integer",
            "minimum": 0,
            "maximum": 100,
            "description": "Advisory. Not a security guarantee."
          },
          "verified": {
            "type": "boolean",
            "description": "True only for human-reviewed artifacts."
          },
          "scanned_at": {
            "type": "string",
            "format": "date-time"
          }
        }
      },
      "InstallRequest": {
        "type": "object",
        "required": [
          "plan_id",
          "artifact_ids"
        ],
        "properties": {
          "plan_id": {
            "type": "string"
          },
          "artifact_ids": {
            "type": "array",
            "items": {
              "type": "string"
            },
            "minItems": 1
          },
          "host": {
            "$ref": "#/components/schemas/Host"
          }
        }
      },
      "InstallStep": {
        "type": "object",
        "required": [
          "artifact_id",
          "method"
        ],
        "properties": {
          "artifact_id": {
            "type": "string"
          },
          "method": {
            "type": "string",
            "enum": [
              "mcp_add",
              "file_write",
              "shell",
              "fetch"
            ]
          },
          "target": {
            "type": "string",
            "description": "Destination path or URI, relative to the project root where applicable."
          },
          "content_url": {
            "type": "string",
            "format": "uri"
          },
          "sha256": {
            "type": "string",
            "pattern": "^[a-f0-9]{64}$",
            "description": "Verify before writing."
          },
          "command": {
            "type": "string",
            "description": "Present only when method is shell or mcp_add. Not executed server-side."
          }
        }
      },
      "Error": {
        "type": "object",
        "required": [
          "error",
          "message"
        ],
        "properties": {
          "error": {
            "type": "string"
          },
          "message": {
            "type": "string"
          },
          "retry_after": {
            "type": "integer"
          }
        }
      }
    }
  }
}