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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.

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Deprecated

FeatureDeprecation SEPDeprecated inMigration pathEarliest removal
RootsSEP-25772026-07-28Pass directories or files via tool parameters, resource URIs, or server configurationFirst revision released on or after 2027-07-28
SamplingSEP-25772026-07-28Integrate directly with LLM provider APIsFirst revision released on or after 2027-07-28
LoggingSEP-25772026-07-28Log to stderr for stdio transports; use OpenTelemetry for observabilityFirst revision released on or after 2027-07-28
HTTP+SSE transportSEP-25962025-03-26Streamable HTTPThree months after SEP-2596 reaches Final
includeContext: "thisServer" / "allServers" (Sampling)SEP-25962025-11-25Omit the field or use "none"Follows Sampling (SEP-2577)
Dynamic Client RegistrationPR #28582026-07-28Client ID Metadata DocumentsFirst revision released on or after 2027-07-28
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.

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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.