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SEP-2596: Specification Feature Lifecycle and Deprecation Policy changedseps/2596-spec-feature-lifecycle-and-deprecation

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2020 requirements.
2121</Note>
2222 
23| Field | Value |
24| ------------- | ------------------------------------------------------------------------------- |
25| **SEP** | 2596 |
26| **Title** | Specification Feature Lifecycle and Deprecation Policy |
27| **Status** | Final |
28| **Type** | Process |
29| **Created** | 2026-04-17 |
30| **Author(s)** | Den Delimarsky ([@localden](https://github.com/localden)) |
31| **Sponsor** | [@localden](https://github.com/localden) |
32| **PR** | [#2596](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2596) |
23| Field | Value |
24| - | - |
25| **SEP** | 2596 |
26| **Title** | Specification Feature Lifecycle and Deprecation Policy |
27| **Status** | Final |
28| **Type** | Process |
29| **Created** | 2026-04-17 |
30| **Author(s)** | Den Delimarsky ([@localden](https://github.com/localden)) |
31| **Sponsor** | [@localden](https://github.com/localden) |
32| **PR** | [#2596](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2596) |
3333 
3434***
3535 
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9090 
9191A specification feature is in exactly one of three states:
9292 
93| State | Meaning | Implementer expectation |
94| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------- |
95| **Active** | The feature is part of the Current specification revision with no planned removal. | Implement per the feature's normative requirements. |
96| **Deprecated** | The feature remains in the specification but is scheduled for removal. A migration path is documented (see below). | New implementations SHOULD NOT adopt the feature. Existing implementations SHOULD migrate before the earliest removal date. |
97| **Removed** | The feature has been deleted from `draft` and will be absent from the next Current revision. It remains documented in the Final revision it last appeared in. | Implementations targeting that next Current revision MUST NOT depend on the feature. |
93| State | Meaning | Implementer expectation |
94| - | - | - |
95| **Active** | The feature is part of the Current specification revision with no planned removal. | Implement per the feature's normative requirements. |
96| **Deprecated** | The feature remains in the specification but is scheduled for removal. A migration path is documented (see below). | New implementations SHOULD NOT adopt the feature. Existing implementations SHOULD migrate before the earliest removal date. |
97| **Removed** | The feature has been deleted from `draft` and will be absent from the next Current revision. It remains documented in the Final revision it last appeared in. | Implementations targeting that next Current revision MUST NOT depend on the feature. |
9898 
9999The term "soft-deprecated" is retired. Existing uses in the specification are reclassified as
100100Deprecated under this policy (see [Transition](#transition)).
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223223 
224224### Roles
225225 
226| Action | Who |
227| ---------------------------------------------- | ----------------------------------------------------------------------------- |
228| Propose deprecation, extension, or restoration | Any contributor, per the SEP process |
229| Sponsor | A Maintainer or Core Maintainer, per the SEP process |
230| Approve a deprecation SEP | Core Maintainers, per the [governance decision process][governance-decisions] |
231| Decide a removal during release preparation | Core Maintainers, per the [governance decision process][governance-decisions] |
232| Approve an extension or restoration SEP | Core Maintainers, per the [governance decision process][governance-decisions] |
233| Approve expedited removal | Core Maintainers, per the [governance decision process][governance-decisions] |
226| Action | Who |
227| - | - |
228| Propose deprecation, extension, or restoration | Any contributor, per the SEP process |
229| Sponsor | A Maintainer or Core Maintainer, per the SEP process |
230| Approve a deprecation SEP | Core Maintainers, per the [governance decision process][governance-decisions] |
231| Decide a removal during release preparation | Core Maintainers, per the [governance decision process][governance-decisions] |
232| Approve an extension or restoration SEP | Core Maintainers, per the [governance decision process][governance-decisions] |
233| Approve expedited removal | Core Maintainers, per the [governance decision process][governance-decisions] |
234234 
235235As with all Core Maintainer decisions, Lead Maintainers retain veto authority over each of the
236236approvals above, per the [governance roles][governance-roles] definition.
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254254permissible window. Removal still follows [Removing a feature](#removing-a-feature): a Core
255255Maintainer decision at release preparation, not an automatic event when the grace period ends.
256256 
257| Feature | Migration target | Earliest removal |
258| ----------------------------------------------- | ------------------------------------ | --------------------------------------- |
259| HTTP+SSE transport | [Streamable HTTP][transports-compat] | Three months after this SEP is Final |
260| `includeContext: "thisServer"` / `"allServers"` | Omit the field or use `"none"` | Follows Sampling ([SEP-2577][sep-2577]) |
257| Feature | Migration target | Earliest removal |
258| - | - | - |
259| HTTP+SSE transport | [Streamable HTTP][transports-compat] | Three months after this SEP is Final |
260| `includeContext: "thisServer"` / `"allServers"` | Omit the field or use `"none"` | Follows Sampling ([SEP-2577][sep-2577]) |
261261 
262262`includeContext` is a parameter of `sampling/createMessage`. [SEP-2577][sep-2577] deprecates the
263263Sampling feature as a whole; the two affected `includeContext` values follow that feature's
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