action postmarkapp_list_sender_signatures { label: "List Sender Signatures" provider: postmarkapp method: GET path: "/senders" encoding: json input: { type: "object" properties: { "X-Postmark-Account-Token": { type: "string" } count: { type: "string" } offset: { type: "string" } } required: ["X-Postmark-Account-Token", "count", "offset"] additionalProperties: false } output: { type: "object" additionalProperties: true } }