zed-industries/zed · error · LoadError

Resuming sessions is not supported by this agent.

Error message

Resuming sessions is not supported by this agent.

What it means

Capability sentinel returned by the ACP connection's resume_session when the agent server's session_capabilities.resume is None, i.e. the server did not advertise session resumption in its initialize response. Any resume_session call against such a server fails immediately with a ready error task; the fault is invoking resume on a non-supporting agent.

Source

Thrown at crates/agent_servers/src/acp.rs:1786

            cx,
        )
    }

    fn resume_session(
        self: Rc<Self>,
        session_id: acp::SessionId,
        project: Entity<Project>,
        work_dirs: PathList,
        title: Option<SharedString>,
        cx: &mut App,
    ) -> Task<Result<Entity<AcpThread>>> {
        if self
            .agent_capabilities
            .session_capabilities
            .resume
            .is_none()
        {
            return Task::ready(Err(anyhow!(LoadError::Other(
                "Resuming sessions is not supported by this agent.".into()
            ))));
        }

        let mcp_servers = mcp_servers_for_project(&project, cx);
        self.open_or_create_session(
            session_id,
            project,
            work_dirs,
            title,
            move |connection, session_id, directories| {
                Box::pin(async move {
                    let response = connection
                        .send_request(
                            directories
                                .into_resume_session_request(session_id.clone(), mcp_servers),
                        )
                        .block_task()

View on GitHub (pinned to 9d272b0363)

Solutions

1. Start a fresh session instead of resuming
2. Use load_session if the agent advertises loading with full history
3. Choose an agent that declares resume capability in its session capabilities

When it happens

Trigger: Thrown at crates/agent_servers/src/acp.rs:1782 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@9d272b0363 (2026-08-20). Data as JSON: /api/errors/5abf611f0c02cc73. Report an issue: GitHub.