STAC MCP Server

# ADR 0005: Optional Planetary Computer Asset Signing Status: Proposed Date: 2025-09-18 ## Context - Planetary Computer assets often require signed URLs for direct access. - Not all catalogs require signing; must remain optional. ## Decision - Add sign_assets bool parameter on item-returning tools (default: false). - If true and catalog host matches Planetary Computer: - Try import planetary_computer and sign item/assets. - Fail gracefully if package missing; include actionable hint. - Do not persist signed URLs in state; sign per response. ## Consequences - Enables immediate asset usability on PC without breaking other catalogs. - Introduces optional dependency and branching logic. ## Alternatives considered - Always sign (rejected; breaks non-PC). - Never sign (rejected; harms usability on PC).