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This page tracks lifecycle changes for ACP Requests for Dialog. For broader ACP announcements, see Updates.
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June 22, 2026
Preview

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model_config Category RFD moves to Preview stage

The RFD for the model_config session configuration option category has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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June 5, 2026
Completed

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Message ID RFD moves to Completed

The RFD for adding agent-generated messageId fields to streamed message chunks has been stabilized and is now part of the protocol. In v1, message IDs are optional on message chunks for compatibility; in v2, they are required. Please review the documentation for more information.
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June 5, 2026
Completed

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Session Context Size and Cost RFD moves to Completed

The RFD for usage_update session notifications has been stabilized and is now a part of the protocol. Agents can report session-level context window size and optional cumulative cost through session/update. Please review the documentation for more information.
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June 5, 2026
Completed

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session/delete RFD moves to Completed

The RFD for allowing clients to delete a given session has been stabilized and is now a part of the protocol. Please review the documentation for more information.
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June 3, 2026
Completed

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_meta Propagation RFD moves to Completed

The RFD for documenting _meta propagation conventions for correlation metadata has been completed and is now part of the protocol documentation. Please review the documentation for more information.
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June 3, 2026
Preview

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Message ID RFD moves to Preview stage for v1

The v1 portion of the RFD for adding message IDs to streamed message chunks has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the v1 behavior is stabilized.
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June 3, 2026
Preview

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Session Usage RFD moves to Preview stage

The RFD for adding usage_update session notifications for context window size and cumulative session cost has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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June 2, 2026
Draft

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v2 Plan Variants RFD moves to Draft stage

The RFD for making item-based plan_update the default v2 plan shape has been moved to Draft stage. Please review the RFD for more information on replacing the old v1 plan update in v2 while the broader Plan Operations RFD continues.
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June 2, 2026
Draft

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End-Turn Token Usage RFD moves to Draft stage

The end-turn token usage portions of the original Session Usage RFD have been split into a separate Draft RFD for further design work. Please review the RFD for more information on the current proposal and provide feedback.
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June 2, 2026
Preview

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session/delete RFD moves to Preview stage

The RFD for allowing clients to delete a given session has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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June 1, 2026
Removed

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Unstable Session Model API removed

The never-stabilized session/set_model API and related session model response fields have been removed from the protocol artifacts. Agents should continue to expose model selection through Session Config Options.
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June 1, 2026
Completed

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Additional Directories RFD moves to Completed

The RFD for allowing clients to specify additional workspace roots for session lifecycle requests has been stabilized and is now a part of the protocol. Please review the documentation for more information.
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May 27, 2026
Draft

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v2 Enum Variant Extension RFD moves to Draft stage

The RFD for reserving _-prefixed enum variants for extensions while preserving non-underscore variants for future ACP versions has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on v2 continues.
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May 27, 2026
Draft

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Plan Operations Support RFD moves to Draft stage

The RFD for adding plan_update and plan_removed session update types has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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May 22, 2026
Completed

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Logout Method RFD moves to Completed

The RFD for the logout method has been stabilized and is now a part of the protocol. Please review the documentation for more information.
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May 21, 2026
Preview

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Additional Directories RFD moves to Preview stage

The RFD for allowing clients to specify additional workspace roots for session lifecycle requests has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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May 17, 2026
Preview

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Logout Method RFD moves to Preview stage

The RFD for adding a logout method to the protocol has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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May 12, 2026
Preview

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Rust SDK based on SACP RFD moves to Preview stage

The RFD for basing the Rust SDK on SACP has been moved to Preview stage now that the initial crate import has been upstreamed to agentclientprotocol/rust-sdk. Please review the RFD for more information on the current proposal and provide feedback before the SDK is stabilized as 1.0.
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May 7, 2026
Draft

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model_config Category RFD moves to Draft

The RFD for the model_config category been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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April 23, 2026
Draft

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v2 Prompting RFD moves to Draft

The RFD for how the prompt lifecycle will work in v2 of the protocol been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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April 23, 2026
Completed

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session/close RFD moves to Completed

The RFD for the session/close method has been stabilized and is now a part of the protocol. Please review the documentation for more information.
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April 22, 2026
Completed

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session/resume RFD moves to Completed

The RFD for the session/resume method has been stabilized and is now a part of the protocol. Please review the documentation for more information.
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April 22, 2026
Draft

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Streamable HTTP & WebSocket Transport RFD moves to Draft stage

The RFD for standardizing a remote ACP transport based on MCP Streamable HTTP with a WebSocket upgrade has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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April 14, 2026
Preview

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session/resume RFD moves to Preview stage

The RFD for adding a session/resume method to the protocol has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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April 14, 2026
Preview

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session/close RFD moves to Preview stage

The RFD for allowing agents to close a given session has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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March 27, 2026
Draft

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Custom LLM Endpoint RFD moves to Draft stage

The RFD for allowing clients to specify custom provider configuration has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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March 24, 2026
Draft

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Additional Directories RFD moves to Draft stage

The RFD for allowing clients to specify additional directories for the agent to access has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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March 9, 2026
Completed

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ACP Registry RFD moves to Completed

The RFD for the initial version of the ACP Registry has been completed. Please review the documentation for more information.

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session_info_update Notification RFD moves to Completed

The RFD for the session_info_update notification has been stabilized and is now a part of the protocol. Please review the documentation for more information.

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session/list RFD moves to Completed

The RFD for the session/list method has been stabilized and is now a part of the protocol. Please review the documentation for more information.
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February 24, 2026
Draft

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Next Edit Suggestions RFD moves to Draft stage

The RFD for allowing agents to provide next edit suggestions has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.

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session/close RFD moves to Draft stage

The RFD for allowing agents to close a given session has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.

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Elicitation RFD moves to Draft stage

The RFD for allowing agents to elicit user input has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.

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Boolean Config Option RFD moves to Draft stage

The RFD for adding boolean config options to the protocol has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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February 20, 2026
Draft

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Delete in Diff RFD moves to Draft stage

The RFD for indicating whether a diff resulted in a file deletion has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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February 18, 2026
Draft

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Message ID RFD moves to Draft stage

The RFD for adding message ids to the protocol has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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February 18, 2026
Preview

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session/list RFD moves to Preview stage

The RFD for the session/list method has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.

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session_info_update RFD moves to Preview stage

The RFD for the session_info_update notification has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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February 10, 2026
Preview

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ACP Registry RFD moves to Preview stage

The RFD for the ACP Registry has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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February 4, 2026
Completed

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Session Config Options RFD moves to Completed

The RFD for adding more generic Session Config Options to the protocol has been stabilized and is now a part of the protocol. Please review the documentation for more information.
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February 4, 2026
Draft

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session/delete moves to Draft stage

The RFD for allowing clients to delete a given session has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.

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Logout method moves to Draft stage

The RFD for allowing clients to logout from an agent connection has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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January 15, 2026
Draft

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Rust SDK based on SACP RFD moves to Draft stage

The RFD for basing the Rust SDK on SACP has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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January 15, 2026
Preview

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Session Config Options RFD moves to Preview stage

The RFD for adding more generic Session Config Options to the protocol has been moved to Preview stage. Please review the RFD for more information on the current proposal and provide feedback before the feature is stabilized.
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January 14, 2026
Draft

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Authentication Methods RFD moves to Draft stage

The RFD for creating additional types of authentication methods has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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January 1, 2026
Draft

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Agent Registry RFD moves to Draft stage

The RFD for creating an Agent Registry has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.

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Session Usage RFD moves to Draft stage

The RFD for adding a new usage_update variant on the session/update notification and usage field on prompt responses in the protocol has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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December 31, 2025
Draft

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Proxy Chains RFD moves to Draft stage

The RFD for adding proxy chain functionality in the protocol has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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December 11, 2025
Draft

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Agent Telemetry Export RFD moves to Draft stage

The RFD for providing more guidance on how agents should export telemetry has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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December 3, 2025
Draft

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session_info_update notification RFD moves to Draft stage

The RFD for adding a new session_info_update variant on the session/update notification in the protocol has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.

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_meta Propagation RFD moves to Draft stage

The RFD for providing more guidance on how the _meta parameter should be used within the protocol has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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November 26, 2025
Draft

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session/resume RFD moves to Draft stage

The RFD for adding a session/resume method to the protocol has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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November 20, 2025
Draft

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$/cancelRequest RFD moves to Draft stage

The RFD for adding a $/cancelRequest method to the protocol has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.

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session/fork RFD moves to Draft stage

The RFD for adding a session/fork method to the protocol has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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November 3, 2025
Draft

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Session Config Options RFD moves to Draft stage

The RFD for adding more generic Session Config Options to the protocol has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.
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October 31, 2025
Draft

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session/list RFD moves to Draft stage

The RFD for adding a session/list method to the protocol has been moved to Draft stage. Please review the RFD for more information on the current proposal and provide feedback as work on the implementation begins.