diff --git a/docs/development/v4-notes/index.mdx b/docs/development/v4-notes/index.mdx index 4a5959545..4344d5328 100644 --- a/docs/development/v4-notes/index.mdx +++ b/docs/development/v4-notes/index.mdx @@ -5,7 +5,7 @@ title: v4.0 Development Notes This directory is the working map of FastMCP v4.0: the complete register of user-facing changes from the MCP Python SDK v2 migration ([PR #4437](https://github.com/PrefectHQ/fastmcp/pull/4437)), plus the forward v4 feature program. It plays three roles at once. 1. **A change register.** Every user-visible change from the migration, organized by subsystem, with a note on how FastMCP handles it (absorbed, bridged, breaking, or deprecated) and where to find it in the diff. This is the [Change Register](/development/v4-notes/change-register). -2. **A feature program.** The forward v4 work — sampling removal, MRTR elicitation, the first-class 2026 client, and the SDK-delegation round-two convergence — each with an explicit status. This is the [Feature Program](/development/v4-notes/feature-program). The shipped side of that program — what a v4 deployment provides on the modern protocol today, including the complete server-side SEP-990 identity assertion implementation — is cataloged in [2026-07-28 Protocol Support](/development/v4-notes/protocol-2026). +2. **A feature program.** The forward v4 work — sampling removal, multi-round-trip elicitation, the first-class 2026 client, and the SDK-delegation round-two convergence — now a mix of shipped and pending. Multi-round-trip guard tools (#4544) and the client's `mode="auto"` default with a partial SDK-composition (#4572/#4574, full composition blocked upstream) have shipped; sampling removal and SDK delegation remain ahead. Each carries an explicit status in the [Feature Program](/development/v4-notes/feature-program). The shipped side — what a v4 deployment provides on the modern protocol today, including the complete server-side SEP-990 identity assertion implementation — is cataloged in [2026-07-28 Protocol Support](/development/v4-notes/protocol-2026). 3. **A review lens.** Because the migration PR is too large to review line by line, the change register is organized so a reviewer can take one subsystem, read its claimed changes, and verify each against the diff. The [Known Gaps](/development/v4-notes/known-gaps) page collects the deliberate xfails and the upstream dependencies that gate the follow-up work. ## Why v4 exists