STAC MCP Server

# ADR 0006: Output Formats — Add JSON Mode Status: Accepted Date: 2025-09-24 ## Context - MCP clients sometimes need machine-readable results for chaining actions. - Current responses are text-only. ## Decision - Add output_format: "text" (default) | "json" to all tools. - JSON mode returns: - For collections/items: compact dicts mirroring STAC fields used today. - For searches: items array plus pagination/conformance metadata when available. - Keep text mode unchanged for backward compatibility. ## Consequences - Enables programmatic consumption in workflows. - Requires careful versioning of response schema and tests. ## Alternatives considered - New parallel tools with -json suffix (rejected; duplicates surface). ## Addendums - 2025-09-18: See ASR 1003 (JSON Output Stability and Compatibility) for non-functional guarantees and compatibility policy. - 2025-09-24: Implemented in feature/json-output-format branch. Tools accept `output_format` param; JSON responses wrapped in single MCP TextContent payload containing compact JSON envelope `{"mode":"json","data":...}`.