Documentation Index
Fetch the complete documentation index at: https://agentclientprotocol.com/llms.txt Use this file to discover all available pages before exploring further.
Updates
Updates and announcements about the Agent Client Protocol
This page is for larger ACP announcements and project updates. For lifecycle changes to Requests for Dialog, see RFD Updates.
<Update label=“July 22, 2026” tags={[“Protocol”]}>
Elicitation is Stabilized
The Elicitation RFD has moved to Completed, and structured form and URL-mode user interactions are now stabilized in ACP.
Agents can request structured non-sensitive input or direct users to secure out-of-band flows, while Clients explicitly advertise the modes they support.
<Update label=“July 20, 2026” tags={[“Protocol”]}>
ACP v2 is Available in Draft
The ACP v2 protocol documentation and schema are now published in Draft form.
<Update label=“July 6, 2026” tags={[“Protocol”]}>
Boolean Config Options are Stabilized
The Boolean Config Option Type RFD has moved to Completed and boolean session configuration options are stabilized.
Agents can now expose native on/off controls, while v1 clients explicitly opt in through the session.configOptions.boolean capability.
<Update label=“June 29, 2026” tags={[“Protocol”]}>
Request Cancellation is Stabilized
The Request Cancellation RFD has moved to Completed and the $/cancel_request notification is stabilized.
Either side can now request cancellation of an outstanding JSON-RPC request by ID without relying on method-specific cancellation.
<Update label=“June 25, 2026” tags={[“SDKs”]}>
Rust and TypeScript SDKs Reach 1.0
The Rust SDK based on SACP RFD has moved to Completed after both the Rust and TypeScript ACP SDKs reached version 1.0.0.
The releases provide stable foundations for building ACP clients, agents, and protocol adapters in both ecosystems.
<Update label=“June 24, 2026” tags={[“Protocol”]}>
Model Config Category is Stabilized
The Model Config Option Category RFD has moved to Completed and the model_config category is stabilized.
Agents can classify model-related parameters such as context size or speed and quality trade-offs so clients can present them alongside the main model selector.
<Update label=“June 5, 2026” tags={[“Protocol”]}>
Message IDs are Stabilized
The Message ID RFD has moved to Completed and optional Agent-generated messageId fields are stabilized in ACP v1.
Message IDs let clients group streamed chunks into individual messages and detect when a new message begins.
<Update label=“June 5, 2026” tags={[“Protocol”]}>
Session Usage Updates are Stabilized
The Session Context Size and Cost RFD has moved to Completed and usage_update session notifications are stabilized.
Agents can now report current context-window utilization and optional cumulative session cost so clients can keep usage displays up to date.
<Update label=“June 5, 2026” tags={[“Protocol”]}>
Session Delete is Stabilized
The Session Delete RFD has moved to Completed and the session/delete method is stabilized.
This gives users a standard way to remove sessions from session history while leaving storage and retention policy to the Agent.
<Update label=“June 1, 2026” tags={[“Protocol”]}>
Additional Workspace Roots are Stabilized
The Additional Workspace Roots RFD has moved to Completed and additionalDirectories is stabilized for session lifecycle requests.
Clients can declare absolute additional workspace roots while cwd remains the primary working directory.
<Update label=“May 21, 2026” tags={[“Protocol”]}>
Logout Method is Stabilized
The Logout Method RFD has moved to Completed and the logout method is stabilized.
This gives clients a standard way to end an authenticated state and let users authenticate again without restarting the ACP connection.
<Update label=“April 23, 2026” tags={[“Protocol”]}>
Session Close is Stabilized
The Session Close RFD has moved to Completed and the session/close method is stabilized.
This gives clients a way to tell agents to cancel in-flight work for a session and free the resources tied to it without tearing down the whole ACP process.
<Update label=“April 22, 2026” tags={[“Protocol”]}>
Session Resume is Stabilized
The Session Resume RFD has moved to Completed and the session/resume method is stabilized.
This gives clients a way to reconnect to an existing session without replaying conversation history, and lets proxies and adapters build session/load semantics on top of the simpler primitive.
<Update label=“April 22, 2026” tags={[“Working Groups”]}>
Transports Working Group
A new Transports Working Group has been formed to standardize remote agent transports like WebSockets and HTTP.
Anna Zhdan (JetBrains / Core Maintainer) and Alex Hancock (Block / Goose) are leading the effort, with a Draft RFD already underway.
<Update label=“March 9, 2026” tags={[“Protocol”]}>
ACP Registry is Released
The ACP Registry RFD has moved to Completed and the initial version of the registry is released.
The registry gives ACP clients a standard way to discover, install, and configure compatible agents without inventing custom integration metadata.
<Update label=“March 9, 2026” tags={[“Protocol”]}>
Session Info Update is Stabilized
The Session Info Update RFD has moved to Completed and the session_info_update notification is stabilized.
This lets agents push session metadata updates to clients in real time so titles and related metadata stay current without polling.
<Update label=“March 9, 2026” tags={[“Protocol”]}>
Session List is Stabilized
The Session List RFD has moved to Completed and the session/list method is stabilized.
This gives clients a standard way to discover existing sessions from an agent for features like history, switching, and cleanup.
<Update label=“February 18, 2026” tags={[“Governance”]}>
Sergey Ignatov joins ACP as Lead Maintainer
Sergey Ignatov from JetBrains is now a Lead Maintainer for ACP.
This reflects the growing collaboration between Zed and JetBrains around ACP and recognizes Sergey’s significant contributions to the protocol.
<Update label=“February 4, 2026” tags={[“Protocol”]}>
Session Config Options are now Stabilized
The Session Config Options RFD has moved to Completed and is stabilized.
This gives agents a flexible way to expose session-level configuration such as models, modes, reasoning levels, and other selectors.
<Update label=“October 24, 2025” tags={[“Protocol”]}>
Implementation information for agents and clients
ACP now allows agents and clients to share implementation details during initialization using the optional clientInfo and agentInfo fields.
This makes it easier to identify which implementation is running, improve compatibility diagnostics, and understand adoption across the ecosystem.
Last updated Oct 08, 2026