zed-industries/zed · error

Unsupported protocol version: {:?}

Error message

Unsupported protocol version: {:?}

What it means

Error "Unsupported protocol version: {:?}" thrown in zed-industries/zed.

Source

Thrown at crates/context_server/src/protocol.rs:57

        client_info: types::Implementation,
    ) -> Result<InitializedContextServerProtocol> {
        let params = types::InitializeParams {
            protocol_version: types::ProtocolVersion(types::LATEST_PROTOCOL_VERSION.to_string()),
            capabilities: types::ClientCapabilities {
                experimental: None,
                sampling: None,
                roots: None,
            },
            meta: None,
            client_info,
        };

        let response: types::InitializeResponse = self
            .inner
            .request(types::requests::Initialize::METHOD, params)
            .await?;

        anyhow::ensure!(
            Self::supported_protocols().contains(&response.protocol_version),
            "Unsupported protocol version: {:?}",
            response.protocol_version
        );

        log::trace!("mcp server info {:?}", response.server_info);

        // Per MCP 2025-06-18, HTTP transport must attach the negotiated version
        // as `MCP-Protocol-Version` on every post-initialize request.
        self.inner
            .set_protocol_version(&response.protocol_version.0);

        let initialized_protocol = InitializedContextServerProtocol {
            inner: self.inner,
            initialize: response,
        };

        initialized_protocol.notify::<types::notifications::Initialized>(())?;

View on GitHub (pinned to bc538def45)

When it happens

Trigger: Thrown at crates/context_server/src/protocol.rs:57 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@bc538def45 (2026-08-16). Data as JSON: /api/errors/76a85e5e0d8c7882. Report an issue: GitHub.