zed-industries/zed · error · LoadError

Loading sessions are not supported by this agent.

Error message

Loading sessions are not supported by this agent.

What it means

load_session restores an existing conversation via ACP session/load, but only when the agent advertised loadSession in its initialize capabilities. When agent_capabilities.load_session is false, the call fails fast with LoadError::Other instead of sending an RPC the agent would reject or mishandle.

Source

Thrown at crates/agent_servers/src/acp.rs:1738

    }

    fn supports_session_additional_directories(&self) -> bool {
        self.agent_capabilities
            .session_capabilities
            .additional_directories
            .is_some()
    }

    fn load_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.load_session {
            return Task::ready(Err(anyhow!(LoadError::Other(
                "Loading 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_load_session_request(session_id.clone(), mcp_servers),
                        )
                        .block_task()
                        .await

View on GitHub (pinned to bc538def45)

Solutions

1. Check agent_capabilities.load_session before offering or performing session load
2. Start a new session instead of loading for agents without the capability
3. Upgrade the agent to a build that advertises session load

Example fix

// before
let thread = connection.load_session(id.clone(), project, dirs, None, cx).await?;

// after — fall back to a new session when resume is unsupported
let thread = if connection.agent_capabilities.load_session {
    connection.load_session(id, project, dirs, None, cx).await?
} else {
    connection.open_session(project, dirs, cx).await?
};

fn supports_session_load(connection: &AcpAgentConnection) -> bool {
    connection.agent_capabilities.load_session
}

Check agent_capabilities.load_session first; if the load fails with this error, degrade gracefully by starting a new session instead of resuming.

When it happens

Trigger: load_session invoked on an ACP agent whose capabilities do not include load_session — stateless agents, older agent versions, or callers that skip the capability check before offering resume.

Common situations: Third-party ACP agents without conversation-resume support; UI that offers 'open previous thread' for every registered agent regardless of capability.

Related errors

• delete_session not supported
• failed to wait for agent server exit: {err}
• session was closed before load completed
• Working directory cannot be empty
• output token limit reached

AI-assisted analysis of zed-industries/zed@bc538def45 (2026-08-16). Data as JSON: /api/errors/8da5c8b90bd5c551. Report an issue: GitHub.