Function useConnection

packages/plugins/mcp/src/sdk/invoke.ts:161–210

(
  connection: McpConnection,
  toolName: string,
  args: Record<string, unknown>,
  elicit: Elicit,
  onToolListChanged: (() => void) | undefined,
)

// ---------------------------------------------------------------------------

const useConnection = (
  connection: McpConnection,
  toolName: string,
  args: Record<string, unknown>,
  elicit: Elicit,
  onToolListChanged: (() => void) | undefined,
): Effect.Effect<unknown, McpInvocationError | McpOAuthReauthorizationRequired> =>
  Effect.gen(function* () {
    installElicitationHandler(connection.client, elicit);
    installToolListChangedHandler(connection.client, onToolListChanged);
    return yield* Effect.tryPromise({
      try: () => connection.client.callTool({ name: toolName, arguments: args }),
      catch: (cause) => {
        if (Predicate.isTagged(cause, "McpOAuthReauthorizationRequired")) {
          return new McpOAuthReauthorizationRequired({
            message: "MCP OAuth re-authorization required",
          });
        }
        // Raised by the fetch adapter when the 403 carried an RFC 6750
        // insufficient_scope challenge (the authProvider path, where the SDK
        // would otherwise consume the challenge before we could see it).
        if (Predicate.isTagged(cause, "McpInsufficientScopeError")) {
          return new McpInvocationError({
            toolName,
            message: `MCP tool call failed for ${toolName}`,
            status: 403,
            insufficientScope: true,
            transportFailure: true,
          });
        }
        const status = httpStatusFromCause(cause);
        // oxlint-disable-next-line executor/no-instanceof-tagged-error -- boundary: MCP SDK protocol failures are its McpError subclass; transport failures use other error shapes
        const protocolFailure = cause instanceof McpError;
        return new McpInvocationError({
          toolName,
          message: `MCP tool call failed for ${toolName}`,
          ...(status === undefined ? {} : { status }),
          ...(!protocolFailure ? { transportFailure: true } : {}),
          ...(isUnknownToolCause(cause, toolName) ? { unknownTool: true } : {}),
          ...(status === 403 && insufficientScopeFromCause(cause)
            ? { insufficientScope: true }
            : {}),
        });
      },
    }).pipe(
      Effect.withSpan("plugin.mcp.client.call_tool", {
        attributes: { "mcp.tool.name": toolName },
      }),
    );
  });

// ---------------------------------------------------------------------------
// Public API