Developer changelog

This changelog covers the Agent API, hosted Model Context Protocol (MCP), portable skills, and developer documentation.

Package changes use the separate TypeScript SDK release notes.

2026-09-05

Channel responses and the SDK expose account text limits and the confirmed X subscription type.
X Basic, Premium, and PremiumPlus accounts support long posts. The server checks eligibility before long AI generation and again before delivery.
Ideas and Boards guides now describe direct capture, Create post, linked posts, and the default Grid view.

Published the initial documented /agent/v1 contract.
Added customer-safe post list and detail routes with opaque cursor pagination.
Added side-effect-free post checks.
Added confirmed and idempotent post edit, reschedule, cancel, and failed-only retry commands.
Added validated multipart media upload with media:write.
Documented the fixed limit of 600 requests per hour for each agent key or OAuth connector.
Published the v1 compatibility policy and the 90-day notice period for planned removals.

Added signed publication lifecycle events for scheduled, published, partial, failed, delayed, reconnect-required, checking, cancelled, and expired results.
Added stable event IDs, HMAC-SHA256 signatures, bounded delivery retries, and customer-safe payloads.
Added TypeScript webhook types and signature verification.

Published setup, permissions, tool, approval, and troubleshooting guidance for hosted MCP.
Added a portable Beacon skill for safe MCP workflows.

Added one Markdown output for each documentation page.
Added a complete corpus, semantic sitemap, agent guide, and XML documentation sitemap.
Added safe testing guidance without claiming that Beacon provides a public sandbox.