Documentation Index
Fetch the complete documentation index at: https://modelcontextprotocol.io/llms.txt Use this file to discover all available pages before exploring further.
Deprecated Features
This page is the registry of specification features that are currently in the Deprecated state under the feature lifecycle and deprecation policy (SEP-2596).
A Deprecated feature remains part of the specification but is scheduled for removal: new implementations SHOULD NOT adopt it, and existing implementations SHOULD migrate before the feature’s earliest removal. The earliest removal marks when a feature becomes eligible for removal; the actual removal is a Core Maintainer decision taken during release preparation and may happen later.
This registry is a derived view kept consistent with the per-feature deprecation notices and changelog entries, which are the normative records.
Deprecated
| Feature | Deprecation SEP | Deprecated in | Migration path | Earliest removal |
|---|---|---|---|---|
| Roots | SEP-2577 | 2026-07-28 | Pass directories or files via tool parameters, resource URIs, or server configuration | First revision released on or after 2027-07-28 |
| Sampling | SEP-2577 | 2026-07-28 | Integrate directly with LLM provider APIs | First revision released on or after 2027-07-28 |
| Logging | SEP-2577 | 2026-07-28 | Log to stderr for stdio transports; use OpenTelemetry for observability | First revision released on or after 2027-07-28 |
| Dynamic Client Registration | PR #2858 | 2026-07-28 | Client ID Metadata Documents | First revision released on or after 2027-07-28 |
includeContext: "thisServer" / "allServers" (Sampling) | SEP-2596 | 2025-11-25 | Omit the field or use "none" | Follows Sampling (SEP-2577) |
| HTTP+SSE transport | SEP-2596 | 2025-03-26 | Streamable HTTP | Three months after SEP-2596 reaches Final |
The HTTP+SSE transport and the includeContext values were already described
as deprecated before the lifecycle policy existed; SEP-2596 reclassifies them
as Deprecated under its transition provisions.
Removed
No features have been removed under this policy yet. When a Deprecated feature is removed, its row moves to this section with a link to the changelog entry recording the removal.
Last updated Oct 08, 2026