ST-2026-078 · Runtimes & developer platforms
Cloudflare Agents SDK v0.20.0 adopts MCP 2026-07-28 and deprecates legacy server APIs
Agents SDK v0.20.0 supports the MCP 2026-07-28 protocol generation, feature-freezes McpAgent and deprecates legacy handler and callTool forms.
Previous state
Agents SDK MCP servers relied on the earlier protocol generation, McpAgent or the v1 createMcpHandler server form.
Current state
Version 0.20.0 supports stateless MCP 2026-07-28 clients and servers with legacy fallback; McpAgent is feature-frozen, createMcpHandler(v1Server, options) is scheduled for removal in the next major version and compatibility callTool overloads are deprecated.
Affected users
Who needs to care
Cloudflare Agents SDK applications operating MCP clients or servers.
Required response
What to do
Adopt the v2 server form, test stateless routes and retain a bounded dual-route path where sessionful features are still required.
Evidence boundary
What the source does not prove
No removal version is announced for McpAgent or the callTool overloads. Sessionful features require a bounded migration until stateless equivalents are available.
Lifecycle history
Dated event sequence
- Agents SDK v0.20.0 released
MCP 2026-07-28 support and the documented legacy deprecations became available.
Evidence ledger
First-party sources
- 01Cloudflare Developers — Agents SDK v0.20.0 and MCP SDK v2
Official SDK changelog · 2026-07-27
Open official source ↗